Uneven Injector Output ***Split from PPR Shim Source ***

[bytes311]

On the topic of PPR shims, the PO installed a Volvo fuel distributor 0 438 100 076 on my car which I believe crosses over from a Volvo 260. Engine runs fine, but when I tried the spray test with the RPM relay jumpered, only one or two injectors spray, and both at random. I've had the injectors professionally cleaned, so I don't know if there's a difference in internal pressure between the Volvo and the DMC FD, but it appears that my PPR also only has one shim. Could that be the problem?

59520

[David T]

There is no direct cross/over from anything to a Delorean as far as the fuel system is concerned. The part number on each part is very application specific. That said, there are other applications close enough that they will work but they were not designed to work optimally for the Delorean. It is also possible to modify parts so that they can work on a Delorean. Inside the F/D the parts have specific profiles, the springs are set to specific pressures, and the passages are drilled to certain sizes. Ideally you should strive to get the correct part if at all possible. It is getting harder and harder as the parts get older and older and the cross/overs also get older and harder to get too. Look to the Delorean vendors to get, if not the correct parts, at least parts that will work. They must have stock of parts for their service business.

[Bitsyncmaster]

On the topic of PPR shims, the PO installed a Volvo fuel distributor 0 438 100 076 on my car which I believe crosses over from a Volvo 260. Engine runs fine, but when I tried the spray test with the RPM relay jumpered, only one or two injectors spray, and both at random. I've had the injectors professionally cleaned, so I don't know if there's a difference in internal pressure between the Volvo and the DMC FD, but it appears that my PPR also only has one shim. Could that be the problem?

59520

If your car runs fine than something is wrong with your test that only showed one or two injectors spraying. Did you press the air plate all the way down to test? If so try the test just pressing about half way down. I have see one car that had the correct FD not spray good with the plate all the way down but would do it fine at half way down.

[bytes311]

Thank you for your responses.

With the air plate halfway or fully down I get the same result. For me, this was a sporadic hot start issue until I installed Bitsyncmaster's solid state RPM relay. Now that the pump auto-primes every time, it hasn't been a real issue, but I still want to address the root cause.

I may just call around and see if any of our vendors are opened to making a FD swap.

[dmcnc]

Does the same thing happen if you swap both injectors with two that don't currently do that?

[Ron]

Thank you for your responses.

With the air plate halfway or fully down I get the same result. For me, this was a sporadic hot start issue until I installed Bitsyncmaster's solid state RPM relay. Now that the pump auto-primes every time, it hasn't been a real issue, but I still want to address the root cause.
$.03

I believe what Dave was saying is that you should ignore the flow when the injectors are fully open...that basically never happens.
The injectors should all open at the ~same time and the output of each should increase equally as the plate is moved down farther. The PPR maintains a constant pressure for the FD. The FD is responsible for maintaining equal pressure-volume to each injector. The injectors have a spring loaded valve that opens when the pressure is above ~4 Bar. So, if the injectors are not opening at the same time or not delivering the same volume of fuel as each other, suspect the FD internals, the injectors, and the injector fuel lines.

To find the root cause try:
Mark the order in which the injectors open. (The spec is has range of 3.5 to 4.1 Bar, so if they are really close, consider them the same.)
Swap the feed hoses, of the first and last injector to open, at the FD end.
If the order is the the same as before, it's not the FD. Otherwise, it is the FD.
If the order changes, it's a hose(s) or injector(s). So swap the two feed hoses, at the injector ends.
If the order now changes, it's the hose. Otherwise, it's the injector.

(If you have put it all back together since posting, you might be able to show that it's the FD without involving injectors 5 & 6, a PITA to get to...)

[David T]

First things first. Check that all of the injectors have the same (and correct!) part #'s. If they were "mixed and matched" they will never spray or open equally. If they are all the same send them out to be cleaned and tested. Once you know all of the injectors are good, if you still get uneven openings and sprays you have a problem with the F/D and that should be sent out. If it isn't the correct part # you should try to get the correct one. If the injector seals are no longer rubbery but are hard, replace them while you are checking the injectors. Checking injectors using the F/D is not a good test. It is possible you have a very low primary pressure and only the injectors with the lowest opening pressure are opening. The test you should be doing is measuring the primary pressure. If it is not right none of the other parts will work right.

[bytes311]

Thank you all for your suggestions. All of my injectors have the same part #, and I've had them cleaned professionally. I also have brand new fuel lines from DPI, so the fuel system itself is clean. I may just bite the bullet and buy the right FD for the car.

The mechanic at the shop where I had my injectors cleaned suggested that I take a rubber mallet to the FD and knock on it a few times which I'm very reluctant to do.

[Bitsyncmaster]

Thank you all for your suggestions. All of my injectors have the same part #, and I've had them cleaned professionally. I also have brand new fuel lines from DPI, so the fuel system itself is clean. I may just bite the bullet and buy the right FD for the car.

The mechanic at the shop where I had my injectors cleaned suggested that I take a rubber mallet to the FD and knock on it a few times which I'm very reluctant to do.

I'm running the same "076" FD on my car with no problems. Not saying something is not wrong with yours.

[bytes311]

I'm running the same "076" FD on my car with no problems. Not saying something is not wrong with yours.

I'm going to get some kjet gauges on it. Since you have the same FD as I, do you know what the ideal primary pressure should be?

[Ron]

5.2 Bar (75.419627 PSI) :)

[Bitsyncmaster]

I'm going to get some kjet gauges on it. Since you have the same FD as I, do you know what the ideal primary pressure should be?

Yes that is the first thing to do. What's nice with the "076: is you have volume adjustment for each injector. I adjusted mine doing the 6 jar test although it was very close to matched before I made the adjustment.

[bytes311]

5.2 Bar (75.419627 PSI) :)

Thanks Ron!

Dave: How do you perform a volume adjustment at each injector with the "076" FD? Didn't know it was possible.

[Bitsyncmaster]

Thanks Ron!

Dave: How do you perform a volume adjustment at each injector with the "076" FD? Didn't know it was possible.

You have a little cap at each cylinder location on the FD. Remove that cap and then there is an adjustment "screw" under that cap. Don't remember which way to turn it to increase the volume but you just run the 6 bottle test a few times.

[bytes311]

You have a little cap at each cylinder location on the FD. Remove that cap and then there is an adjustment "screw" under that cap. Don't remember which way to turn it to increase the volume but you just run the 6 bottle test a few times.

I'm at work, but here is an old photo of my FD. My "076" doesn't have adjustable screws. :(

59553

59554

[Bitsyncmaster]

Here is mine.

So it looks like one of us has a unit someone has changed the top.

[dn010]

According to photos, the 076 is not supposed to have any adjustment screws on it. You probably have a 077 upper half.

[Bitsyncmaster]

According to photos, the 076 is not supposed to have any adjustment screws on it. You probably have a 077 upper half.

Interesting. I do see photos on Hervey's web page shows it not adjustable. I looked closely at the top half and there are no marks or casting info on it. Both halfs are cast iron. I see some FDs are cast aluminum. I wonder what each half controls.

[bytes311]

Just to be clear that I'm buying the correct set of gauges, will this work?

https://www.ebay.com/itm/3420-FUEL-INJECTION-PRESSURE-TESTER-BOSCH-K-JETRONIC-C-I-S-MADE-IN-USA/202100252799?_trkparms=aid%3D222007%26algo%3DSIM.M BE%26ao%3D2%26asc%3D20131003132420%26meid%3D95cb3d d48eaf49ff8cfb64d36856f6b2%26pid%3D100005%26rk%3D1 %26rkt%3D3%26sd%3D312370376340%26itm%3D20210025279 9&_trksid=p2047675.c100005.m1851

[Bitsyncmaster]

Just to be clear that I'm buying the correct set of gauges, will this work?

https://www.ebay.com/itm/3420-FUEL-INJECTION-PRESSURE-TESTER-BOSCH-K-JETRONIC-C-I-S-MADE-IN-USA/202100252799?_trkparms=aid%3D222007%26algo%3DSIM.M BE%26ao%3D2%26asc%3D20131003132420%26meid%3D95cb3d d48eaf49ff8cfb64d36856f6b2%26pid%3D100005%26rk%3D1 %26rkt%3D3%26sd%3D312370376340%26itm%3D20210025279 9&_trksid=p2047675.c100005.m1851

Yes that looks like it will work.

[David T]

While it "looks" correct, can't tell from the picture if it comes with the necessary fittings to connect to the Delorean version of the K-Jet system. The description mentions an auxiliary kit of adapters. You may need it.

[bytes311]

So I received my KJet tools in the mail yesterday. I hooked it up in line between the FD (top post) and the large bolt on the WUR with the valve positioned on the WUR side.

I closed the valve and jumpered my RPM relay to test Primary Pressure. My first reading was 25 PSI. That didn't seem right, so I disconnected and reconnected the jumper wire and saw the gauge rise to about 45 PSI. Very low reading according to the workshop manual.

I then tested my Control Pressure. I re-installed the RPM relay, opened the valve and started the engine. Cold, it started off low, but then it quickly elevated to about 3.3-3.4 bar, so about 47 PSI. I blipped the throttle and the pressure dipped and recovered. That seemed normal.

I found some washers in my toolbox and decided to shim my PPR spring to get Primary Pressure up to 70-75 PSI. For some reason it would only go up to 65 PSI. I figured that's better than what it was, so I fired up the engine. My Control Pressure jumped to 80 PSI constant. I shut the engine off and started it up again. Same result, 80 PSI.

So, now I'm wondering if my my FD and WUR (both refurb by the PO from the same company at presumably the same time) are calibrated together for good Control Pressure at 45 PSI Primary Pressure? Or does that not make sense at all? I don't know anymore. I'll also add that I blew air through the inlets on the WUR and it blew out clean.

[Ron]

No, they can't be calibrated like that.
If I'm reading correctly, something doesn't add up here -- You can't have 80 psi Control pressure unless there is at least 80 psi Primary pressure, because the WUR/CPR bleeds off Primary pressure to obtain the Control pressure...

[MikeWard]

Can you do me a favour and post some pictures of the pressure test kit as you have it setup on the car?

I was assisting a fellow US owner a couple of weeks ago and he had a similar issue with erroneous readings, and it came down to a connection on the pressure tester he was using.

[bytes311]

No, they can't be calibrated like that.
If I'm reading correctly, something doesn't add up here -- You can't have 80 psi control pressure unless there is at least 80 psi Primary pressure, because the WUR/CPR bleeds off primary pressure to obtain the control pressure...

That's what has me confused. My Primary Pressure is topped out at approx. 64 PSI.

59955

I can confirm this with the RPM Relay jumpered and the valve on the gauge set closed. When I switch it over to read Control Pressure (valve opened and RPM relay connected and engine running) it shoots up to 80 PSI.

The Control Pressure was around 47 PSI before I added several shims to the PPR spring as shown below.

59956

[bytes311]

Can you do me a favour and post some pictures of the pressure test kit as you have it setup on the car?

I was assisting a fellow US owner a couple of weeks ago and he had a similar issue with erroneous readings, and it came down to a connection on the pressure tester he was using.

59957

I'm at work right now but I took this picture of my setup from last night.

[Ron]

Have you checked the both with the engine running since shimming?

[bytes311]

Have you checked the both with the engine running since shimming?

No, just the Control Pressure. I didn't check Primary Pressure with the engine running.

[Ron]

I looks like you have the original line from the FD to WUR/CPR still hooked up in the pic??

[bytes311]

I looks like you have the original line from the FD to WUR/CPR still hooked up in the pic??

Correct. The kit came with banjo bolt fittings. Did I hook it up wrong? :jawdrop:

59958

[Ron]

Remove it and prepare for a smile on your face:)


EDIT: Hook up on page D:02:02 in WS manual

[bytes311]

Remove it and prepare for a smile on your face:)

Remove the hose between the FD and WUR? I'll have to look at what fittings I have, as I don't think I have fittings that can delete the fuel line entirely from the setup. I think I only have banjo fittings but I'll look again.

[Ron]

We're not on the same page-- BRB

OK-- Remove the red hose...i.e you should of replaced the hose with the tester.

59959

[bytes311]

We're not on the same page-- BRB

I'm dumb. So disconnect the FD to the WUR hose at the WUR side, and connect it to the gauge, then connect the other end of the gauge to the WUR.

[bytes311]

Gotcha! I'll give that a shot, thanks! :)

[Ron]

Glad to help!

I think what you said last is the way the manual has it, but my last gauge set set looks like yours and it had enough fittings to just swap it all out....takes less iirc.


EDIT: Almost forgot +1 Mike!

[MikeWard]

59957

I'm at work right now but I took this picture of my setup from last night.

Ah - as Ron has already mentioned, it's does not appear to be hooked up correctly. Here is the extract here from the workshop manual for easy reference.
59960
To note, none of the test kit is connected to the fuel distributor. The only line you need to remove is the larger of the two lines on the control pressure regulator (or WUR if you prefer).


Here is an example of a kit connected.
59962

One point of note re erroneous readings, the owner I assisted with this a couple of weeks ago found that the quick release connection on the test kit was the source of his erroneous pressure readings. He subsequently swapped that connection out and held the line in place with a jubilee clip as per the below pic.
59961
I would perhaps connect your kit correctly first, and if you are still getting erroneous readings, then make the change to that quick release connection.

Finally, here is a video of the pressure kit in action, with all pressures within spec.
https://youtu.be/NMYH2WN6rzY

[bytes311]

Thanks fellas. I'll connect it the right way and reassess.

[bytes311]

So, after connecting the fuel pressure gauge the proper way, here are the results:

Primary Pressure - 67 PSI: 59963
Control Pressure - 46 PSI: 59964

Video: https://youtu.be/VBXJ8Hf5ZjI

I could only install two shims. Any more and Primary Pressure goes above 75 PSI and Control Pressure above 65 PSI. I also noticed that my Control Pressure goes up or down depending on my mixture setting. I had to re-adjust my mixture every time I added or subtracted a shim.

Are these pressures acceptable?

Edit: I must also add that the "shims" are basically washers from around my garage, and are not sized for this application.

Thanks!

[Ron]

Acceptable pressures per WSM D:02:01 are:
Primary: 71.1 - 79.7 psi
Control: 49.3 - 55.1 psi (Warm, Vacuum port to delay valve disconnected)

You have to reset the mixture (CO dwell) when you replace just about any major part...
Always last, breather installed, hole plugged.

[bytes311]

Acceptable pressures per WSM D:02:01 are:
Primary: 71.1 - 79.7 psi
Control: 49.3 - 55.1 psi (Warm, Vacuum port to delay valve disconnected)

You have to reset the mixture (CO dwell) when you replace just about any major part...
Always last, breather installed, hole plugged.

Shoot, I'm still too low then. I guess I should purchase the shim kit because my washers are all the same thickness, and three shims bump both Primary and Control pressure up to 70 PSI, with mixture re-adjusted.

[Bitsyncmaster]

Shoot, I'm still too low then. I guess I should purchase the shim kit because my washers are all the same thickness, and three shims bump both Primary and Control pressure up to 70 PSI, with mixture re-adjusted.

If your control pressure runs 70 PSI, that suggests your WUR regulator is shot.

[MikeWard]

Shoot, I'm still too low then. I guess I should purchase the shim kit because my washers are all the same thickness, and three shims bump both Primary and Control pressure up to 70 PSI, with mixture re-adjusted.
The shims only affect primary pressure, they should have zero impact on control pressure, if it does then something else is up. 70PSI is way out for control pressure - as Ron noted it should be a max of 55psi.

To confirm, when you are conducting the pressure tests you have both of the vac connections on the CPR disconnected and the hoses plugged, and the electrical connection on the CPR disconnected? Disconnecting the electrical connection will prevent the heating element raising the control pressure and allow you to monitor the pressure as the CPR naturally warms up from the temperature of the engine. A handy tool to have is a laser thermometer which you can use to periodically take measure the temperature of the CPR casing, then note the pressure, and compare both readings to the graph in the workshop manual.
59965

When ordering the shim kit, I would also recommend ordering the o-ring kit for the pressure regulator and replace those 'while you're in there' https://www.deloreango.com/us/hot-start-o-ring-kit.html


Can you also advise on the below as it will impact the advice given.
-Part numbers of the control pressure regulator and fuel distributor if they are not stock DeLorean parts
-Type of exhaust system you are running; e.g. fully stock with cat, fully stock with cat bypass, stock manifolds with bypass and custom/vendor rear silencer, full free-flow exhaust system etc
-What grade fuel do you use in your car, regular or premium?

[bytes311]

The shims only affect primary pressure, they should have zero impact on control pressure, if it does then something else is up. 70PSI is way out for control pressure - as Ron noted it should be a max of 55psi.

To confirm, when you are conducting the pressure tests you have both of the vac connections on the CPR disconnected and the hoses plugged, and the electrical connection on the CPR disconnected? Disconnecting the electrical connection will prevent the heating element raising the control pressure and allow you to monitor the pressure as the CPR naturally warms up from the temperature of the engine. A handy tool to have is a laser thermometer which you can use to periodically take measure the temperature of the CPR casing, then note the pressure, and compare both readings to the graph in the workshop manual.
59965

When ordering the shim kit, I would also recommend ordering the o-ring kit for the pressure regulator and replace those 'while you're in there' https://www.deloreango.com/us/hot-start-o-ring-kit.html


Can you also advise on the below as it will impact the advice given.
-Part numbers of the control pressure regulator and fuel distributor if they are not stock DeLorean parts
-Type of exhaust system you are running; e.g. fully stock with cat, fully stock with cat bypass, stock manifolds with bypass and custom/vendor rear silencer, full free-flow exhaust system etc
-What grade fuel do you use in your car, regular or premium?

That's one thing I didn't try - plug up the vacuum ports and disconnect the electrical plug. I left everything as is with the engine running while monitoring pressures.

I can't find the original part number for the Warm Up Regulator, but both regulator and fuel distributor have a re-manufactured sticker by "Fuel Injection Corp. USA", so I assumed that the PO had both units rebuilt or swapped at one point. The company still exists, in fact I found out they're based out of Tracy, CA which is 30 miles from me.

59968

Fuel Distributor is 0 438 100 076, which I believe is a Volvo unit. 59967

I'm running all stock with a catalytic converter and I use only regular octane 87 gasoline.

My car runs perfectly fine otherwise. What prompted me to check the pressure to begin with was my occasional hot start issue. I suspected that my Primary Pressure was low since my FD wasn't original to the car. I didn't think shimming would also affect the Control Pressure like it does. Now I'm chasing another issue it seems.

[MikeWard]

It's certainly worth retesting with the vac pipes disconnected, plugged and electrical connection disconnected.

I had a quick look and it appears that the 076 distributor is from a Volvo 260.

Re the CPR model number, it should be stamped on the top of the casing as circled in the below pic.
59969

The reason I'm asking is to determine if you have a matching set of Volvo parts, or if it's a mismatch of Volvo and DeLorean. On that note, what is the part number the air metering unit on your car? Stock DeLorean should be 0-438-120-132

[bytes311]

It's certainly worth retesting with the vac pipes disconnected, plugged and electrical connection disconnected.

I had a quick look and it appears that the 076 distributor is from a Volvo 260.

Re the CPR model number, it should be stamped on the top of the casing as circled in the below pic.
59969

The reason I'm asking is to determine if you have a matching set of Volvo parts, or if it's a mismatch of Volvo and DeLorean. On that note, what is the part number the air metering unit on your car? Stock DeLorean should be 0-438-120-132

Oh interesting, I didn't know it was stamped. I'll take a look at it this evening. I'll also look for the part number on the air metering unit. Thanks!

[Ron]

$.02

That is a non DeLorean type WUR/CPR because it does not have ports to utilize the delay valve. So, nothing to plug. The delay valve only matters for acceleration enrichment when the engine is below 120F. I've never seen it really matter even on weaker autos.:)

I'd suggest, as a test, file another washer down and use it to get the primary pressure between 71 and 79 psi (ok per manual). Then work on the control pressure.

NOTE: If your primary and control pressure is the same, you probably have a problem with the gauge setup or similar preventing the WUR/CPR from returning fuel to the tank, or , a defective WUR/CPR as Dave mentioned (which doesn't sound right according to the way it has acted until now). Worrying about the control pressure otherwise, at this point, is useless, imho.

EDIT: You do NOT remove the WUR/CPR electrical plug when using the chart at D:02:01 (posted above). ...this applies to D or non-D WUR/CPRs.

[bytes311]

That is a non DeLorean type WUR/CPR because it does not have ports to utilize the delay valve. So, nothing to plug. The delay valve only matters for acceleration enrichment when the engine is below 120F. I've never seen it really matter even on weaker autos.:).

Mine or the picture above? Mine has vacuum ports on either side. :) 59970

With two shims, there's a noticeable pressure difference between Primary and Control. By turning the valve on the gauge with engine running I can see the two pressures move up or down (depending on valve position). With three shims, both pressures are at a constant 70 PSI, with no dips or changes in pressure when turning the valve.

I'll file down a shim as suggested to get Primary up to spec. I just don't want to run the risk of ruining my engine or blowing out a fuel line if the Control Pressure is indeed 70 PSI.

[Ron]

'while you're in there' https://www.deloreango.com/us/hot-start-o-ring-kit.html

Hey Mike,

I checked out that link and the kit appears to service (or be a cross between?) the old and new PPRs. Too many o-rings for early style and missing one for late, maybe...
(Or maybe I'm missing something ;-)

You'll see what I mean in the pic:

59972

[Ron]

Mine or the picture above? Mine has vacuum ports on either side. :) 59970

With two shims, there's a noticeable pressure difference between Primary and Control. By turning the valve on the gauge with engine running I can see the two pressures move up or down (depending on valve position). With three shims, both pressures are at a constant 70 PSI, with no dips or changes in pressure when turning the valve.

I'll file down a shim as suggested to get Primary up to spec. I just don't want to run the risk of ruining my engine or blowing out a fuel line if the Control Pressure is indeed 70 PSI.

LOL, I guess "that" is a bit vague, sorry! -- Any WUR w/o the ports is not DMC. In any case, it is not related to the problem, assuming the unit is not defective.

The pressures will rise ~equally until the WUR starts dumping fuel back to the tank at its set pressure(s).
I'm with you on blowing a hose etc. If you have the fittings, dump the WUR's return line into a large container to make sure the WUR is able to do its job. There will be plenty coming out to tell with. You must plug the port on the FD where it connects or fuel will escape from the FD!!!

[Ron]

Thinking about both pressures @ 70 psi
It doesn't make sense with the previous... But just in case, are you 100% sure the return line from your WUR is connected to the FD as with orange below (ie not swapped with small FV line at FD)?
59980

[MikeWard]

Hey Mike,

I checked out that link and the kit appears to service (or be a cross between?) the old and new PPRs. Too many o-rings for early style and missing one for late, maybe...
(Or maybe I'm missing something ;-)

You'll see what I mean in the pic:

59972
That's interesting. I can't say I have ever see the type shown on the left in that picture, and I've shimmed a fair few PPR's over the years, they have always been the type shown on the right. What manual is that diagram from?

The kit is intended for hot start issues, it's not intended to be a PPR rebuild kit which I would assume is the reason that it doesn't come with the third o-ring you identify in the diagram.


EDIT: You do NOT remove the WUR/CPR electrical plug when using the chart at D:02:01 (posted above). ...this applies to D or non-D WUR/CPRs.I would disagree with the manual in that respect. I was taught to always disconnect it along with the vac pipes, and use a laser thermometer to monitor the casing/pressure and reference against the graph as it warms up naturally.

[bytes311]

Thinking about both pressures @ 70 psi
It doesn't make sense with the previous... But just in case, are you 100% sure the return line from your WUR is connected to the FD as with orange below (ie not swapped with small FV line at FD)?
59980

That line in particular appears to be connected correctly according to the diagram.
59982

[Ron]

Dang...That end was chopped off in the other pic and the pressure would act just like what it is doing now.
If you do try dumping the WUR return into a container while the pressures are both high and ~equal and a lot of fuel doesn't come out of the return line, look for foreign material at the WUR ports and inside the PPR. The passage in the FD for the WUR return is very small...just right to allow a piece of an o-ring to push up against the PPR and restrict the fuel flow.
Sounds like trash has came loose and/or the WUR just took a dive...

[bytes311]

Dang...That end was chopped off in the other pic and the pressure would act just like what it is doing now.
If you do try dumping the WUR return into a container while the pressures are both high and ~equal and a lot of fuel doesn't come out of the return line, look for foreign material at the WUR ports and inside the PPR. The passage in the FD for the WUR return is very small...just right to allow a piece of an o-ring to push up against the PPR and restrict the fuel flow.
Sounds like trash has came loose and/or the WUR just took a dive...

Behind the large banjo bolt on the WUR is what appears to be a brass screen/filter. It doesn't look dirty, and I'm able to blow compressed air through it and out the other port. Can this screen be removed to determine whether there is something restricting flow on the inside of it?

[MikeWard]

Behind the large banjo bolt on the WUR is what appears to be a brass screen/filter. It doesn't look dirty, and I'm able to blow compressed air through it and out the other port. Can this screen be removed to determine whether there is something restricting flow on the inside of it?
The CPR should have a fine mesh filter.
59984

Unfortunately (and particularly on American rebuilt units) it is typical to see the original filter swapped out for a sintered style brass filter. I can't say if that restricts/impedes flow, we are fortunate in the UK that we have the legendary Ken Mills Injection who can overhaul CPR and fuel distributors to oem factory spec (as sold via DeLoreanGo). One for the connoisseurs where only the best will do.

There is a high probability of destroying the filter if you try to remove it.

[Ron]

Behind the large banjo bolt on the WUR is what appears to be a brass screen/filter. It doesn't look dirty, and I'm able to blow compressed air through it and out the other port. Can this screen be removed to determine whether there is something restricting flow on the inside of it?
If that screen is blocked, it would act exactly like it is now (pressures always equal). But that is the inlet port -- Trash collects on the external side of the screen... Fuel goes through the screen and a valve then back to the FD port that dumps into the tank. Passing the test in my last post would eliminate the entire assembly WRT blockage. :wink:

[Ron]

I finally found an ancient backup CD I misplaced. Below is a pic from a temp directory where I kept things I was working on.

59985
(I can't remember where I got this, who to credit, or how much I butchered it ;-)

[Ron]

That's interesting. I can't say I have ever see the type shown on the left in that picture, and I've shimmed a fair few PPR's over the years, they have always been the type shown on the right. What manual is that diagram from?

The kit is intended for hot start issues, it's not intended to be a PPR rebuild kit which I would assume is the reason that it doesn't come with the third o-ring you identify in the diagram.
Couldn't find where that came from...I'll look more later.
Meanwhile check this out:
"In order to fully seal off the control-pressure circuit with absolute certainty when the engine has been switched off, and at the same time to maintain the pressure in the fuel circuit, the return line of the warm-up regulator is fitted with a check valve. This (push-up) valve is attached to the primary-pressure regulator and is held open during operation by the pressure-regulator plunger. When the engine is switched off and the plunger of the primary-pressure regulator returns to its zero position, the check valve is closed by a spring (Figure 17)."

59986
(Bosch, "Gasoline Fuel-Injection, System K-Jetronic, Technical Instruction", Pg. 20-21.)

The 3rd o-ring is for the check (push-up) valve and it is all about rest pressure, no?



I would disagree with the manual in that respect. I was taught to always disconnect it along with the vac pipes, and use a laser thermometer to monitor the casing/pressure and reference against the graph as it warms up naturally.
I guess it wouldn't really mater if all you were going to do was check the pressures (as is the case here). But I always left it connected because I've never seen a manual call for its removal (not that that means one doesn't lol), and it would definitely have an effect on the info contained in the following charts for example (because time is involved).

59987
(...,Pg 27)

[Ron]

Another manual answers both questions:

59991

59992

=====

I found 4 different types of WUR/CPRs (sorry about poor image):
59993
======

Couldn't find the source for the pic with 2 PPR designs.
FWIW, one says early v/s late happened "about 1980".

[bytes311]

Thanks for sharing your documentation, Ron!

Here are my part numbers:

Warm-Up Regulator: Bosch 0 438 140 066 59998
Fuel Distributor : Bosch 0 438 100 076 59999
Metering Unit: Bosch 0 438 120 132 052 60000

I removed the extra shims and put the fuel system back together for now. I think when it ran at 70 PSI it knocked loose some varnish trapped in the FD because there was a bit of yellow gunk on the WUR inlet screen. That screen was clean before I started pressure testing the system.

Edit: The tank is clean of debris as well, so it must have come directly from the FD.

[MikeWard]

Couldn't find where that came from...I'll look more later.
Meanwhile check this out:
"In order to fully seal off the control-pressure circuit with absolute certainty when the engine has been switched off, and at the same time to maintain the pressure in the fuel circuit, the return line of the warm-up regulator is fitted with a check valve. This (push-up) valve is attached to the primary-pressure regulator and is held open during operation by the pressure-regulator plunger. When the engine is switched off and the plunger of the primary-pressure regulator returns to its zero position, the check valve is closed by a spring (Figure 17)."

59986
(Bosch, "Gasoline Fuel-Injection, System K-Jetronic, Technical Instruction", Pg. 20-21.)

The 3rd o-ring is for the check (push-up) valve and it is all about rest pressure, no?

If we're talking about the same o-ring then I believe it is the o-ring at the end of the pressure regulator assembly (circled below) which is responsible for sealing off the flow when the engine is turned off.
60001
Operation of the regulator is briefly touched on in this video which gives a high level overview of the K-Jetronic system. https://youtu.be/a4fJAfXYxWk?t=345

The operation of the CPR is also covered a little later on in that video: https://youtu.be/a4fJAfXYxWk?t=787

It is well worth watching the entire video for those who have 20 minutes to spare and want to get a basic understanding of the operation of k-jet.

Thanks for sharing your documentation, Ron!

Here are my part numbers:

Warm-Up Regulator: Bosch 0 438 140 066 59998
Fuel Distributor : Bosch 0 438 100 076 59999
Metering Unit: Bosch 0 438 120 132 052 60000

I removed the extra shims and put the fuel system back together for now. I think when it ran at 70 PSI it knocked loose some varnish trapped in the FD because there was a bit of yellow gunk on the WUR inlet screen. That screen was clean before I started pressure testing the system.

Edit: The tank is clean of debris as well, so it must have come directly from the FD.
Thanks for confirming the part numbers.
After you removed the shims that you'd added, what did it reduce the primary pressure to?

DeLorean - 2.8 PRV B28F Bosch part numbers for reference:
-DeLorean Fuel Distributor: 0-287-402-023
-Delorean Control Pressure Regulator: 0-438-140-066
-DeLorean Air Metering Unit: 0-438-120-132
-DeLorean Ignition Distributor: 0-287-402-023
-DeLorean Fuel Injector: 0-437-502-022

Parts wise the odd one out on your car is the FD (assuming the other components the above list are stock DeLorean), the other parts match up to stock DeLorean. That's not to say that the Volvo FD won't function correctly - I myself am running a full set of Volvo fuelling on my car, it can and does work, and works well!

[Patrick C]

Thanks for sharing your documentation, Ron!

Here are my part numbers:

Warm-Up Regulator: Bosch 0 438 140 066 59998
Fuel Distributor : Bosch 0 438 100 076 59999
Metering Unit: Bosch 0 438 120 132 052 60000

I removed the extra shims and put the fuel system back together for now. I think when it ran at 70 PSI it knocked loose some varnish trapped in the FD because there was a bit of yellow gunk on the WUR inlet screen. That screen was clean before I started pressure testing the system.

Edit: The tank is clean of debris as well, so it must have come directly from the FD.
I will be selling a complete, 100% working K-Jet system that I just removed from my car last weekend. If you think you might be interested, PM me.

[bytes311]

After I removed the shims, primary pressure hovered around 65 PSI.

I just spoke with somebody at the company where the PO purchased the refurbed WUR. They said they will straight up exchange my core with a rebuilt unit for $220. Apparently they receive and rebuild DeLorean parts from all over the country (US). By description they think my WUR is plugged or toast.

I should have stated this earlier but I didn't think about it until now: On cold mornings I have to wait a few minutes for the engine to warm up before I can take it for a drive. I chalked this up as being a toasted heater element inside the WUR because the car ran fine otherwise. Perhaps the WUR was/is on it's way out, or already dead?

[Ron]

If we're talking about the same o-ring then I believe it is the o-ring at the end of the pressure regulator assembly (circled below) which is responsible for sealing off the flow when the engine is turned off.
60001
Not that one. Tyhat one is one of the two that comes in the kit you linked to (#1 in the discussion post 52). It seems a third one marked with a "?" in post 52 and inside the section marked with an arrow in your pic below just isn't included in the kit. It's only job is to "fully seal off the control-pressure circuit with absolute certainty when the engine has been switched off " as in post 59, so it should be in the kit, imho.
60005

EDIT:
60006

[Ron]

After I removed the shims, primary pressure hovered around 65 PSI.

I just spoke with somebody at the company where the PO purchased the refurbed WUR. They said they will straight up exchange my core with a rebuilt unit for $220. Apparently they receive and rebuild DeLorean parts from all over the country (US). By description they think my WUR is plugged or toast.

I should have stated this earlier but I didn't think about it until now: On cold mornings I have to wait a few minutes for the engine to warm up before I can take it for a drive. I chalked this up as being a toasted heater element inside the WUR because the car ran fine otherwise. Perhaps the WUR was/is on it's way out, or already dead?Did the control pressure go to 65 as well?

If it was blocked off, letting it warm up wouldn't allow it to start running in a reasonable manner at all.

[bytes311]

Did the control pressure go to 65 as well?

If it was blocked off, letting it warm up wouldn't allow it to start running in a reasonable manner at all.

No, the control pressure stayed around 47 PSI. It's only when I add additional shims does the control pressure increase to about the same as primary pressure.

[Ron]

Please let me explain it another way:
If the WUR or its return or the FD port they go to is blocked, the control pressure will match the primary pressure, absotively posilutely!

[bytes311]

Please let me explain it another way:
If the WUR or its return or the FD port they go to is blocked, the control pressure will match the primary pressure, absotively posilutely!

That's what I don't quite understand, and please forgive my ignorance.

It acts like there is a blockage when I add shims, but otherwise without additional shims it maintains 47 PSI control and 65 PSI primary, albeit lower than spec. So the problem could be blockage in the FD or the WUR or both? If I disconnect the return line to the fuel pump I should see a good flow of fuel, correct?

[Ron]

That's what I don't quite understand, and please forgive my ignorance.

It acts like there is a blockage when I add shims, but otherwise without additional shims it maintains 47 PSI control and 65 PSI primary, albeit lower than spec. So the problem could be blockage in the FD or the WUR or both? If I disconnect the return line to the fuel pump I should see a good flow of fuel, correct?Sorry...I didn't mean to imply anything like that! -- It seemed like you were about to drop some bucks w/o trying the test(s)...

Yes and Yes! As I said before, the WUR dumps primary pressure to create control pressure. If it can't dump the fuel because of a blockage nothing changes and they will always match.

Restricting only when it goes over 65 is odd! So, since you also started seeing trash, I'd go back to cleaning it out from the fuel filter on then trying the test. If it passes, start from scratch with the gauges.

EDIT:
To be clear- I should have said, "Blocking" (total restriction), instead of, "Restricting only...."

[bytes311]

Sorry...I didn't mean to imply anything like that! -- It seemed like you were about to drop some bucks w/o trying the test(s)...

Yes and Yes! As I said before, the WUR dumps primary pressure to create control pressure. If it can't dump the fuel because of a blockage nothing changes and they will always match.

Restricting only when it goes over 65 is odd! So, since you also started seeing trash, I'd go back to cleaning it out from the fuel filter on then trying the test. If it passes, start from scratch with the gauges.

EDIT:
To be clear- I should have said, "Blocking" (total restriction), instead of, "Restricting only...."

Thanks Ron! I'll perform some more tests tonight. :)

[bytes311]

Silly question, but if I disconnect the return line between the WUR and the FD at the FD side and place the hose in a jerrycan and jumper the RPM relay, is that opened port on the FD going to spray fuel?

[Ron]

Absotively posilutely!

...
You must plug the port on the FD where it connects or fuel will escape from the FD!!!

[MikeWard]

Not that one. Tyhat one is one of the two that comes in the kit you linked to (#1 in the discussion post 52). It seems a third one marked with a "?" in post 52 and inside the section marked with an arrow in your pic below just isn't included in the kit. It's only job is to "fully seal off the control-pressure circuit with absolute certainty when the engine has been switched off " as in post 59, so it should be in the kit, imho.
60005

EDIT:
60006
Ah I see what you mean.

I'm sure if someone was to take the time to remove that part, take measurements of the i/d, o/d and thickness of the o-ring and then get in touch with Arran at DeLoreanGo to provide that info, he could look to add that o-ring into the kit.

[DeLoreanGo Arran]

That o-ring is already in the fuel distributor rebuild kit, but as far a "quick fix hot start" is concerned it is only ever the one on the very tip that is the problem as it is a moving part. The one on the outside of the shaft and the copper washer are also provided in the "quick kit" because they get disturbed when you replace that o-ring. The (third) internal one is something you'd only ever touch as part as a more in-depth rebuild, hence why it's in the full rebuild kit.

[Bitsyncmaster]

That o-ring is already in the fuel distributor rebuild kit, but as far a "quick fix hot start" is concerned it is only ever the one on the very tip that is the problem as it is a moving part. The one on the outside of the shaft and the copper washer are also provided in the "quick kit" because they get disturbed when you replace that o-ring. The (third) internal one is something you'd only ever touch as part as a more in-depth rebuild, hence why it's in the full rebuild kit.

I have had a few customers complaining of hard cold starts which they seem to find starting better with the CSV pulled. Hence their mixture seems to rich. One guy sent a video of his air plate which you could see bump up a little during his cold start. I wonder if that internal O-ring has anything to do with that cold start problems.

[bytes311]

Absotively posilutely!

Oops, I missed that. Thanks Ron.

So I took my WUR to that fuel injection shop and they bench-tested it on the spot. Pressures are good and within spec, which I believe now makes the FD the prime suspect.

[David T]

During a cold start the motor is starting on the fuel from the CSV til the pressure gets up high enough for the injectors to start spraying. Without the CSV you will be cranking the motor longer till the fuel pressure gets high enough for the injectors to spray It is possible to have the wrong plug on the CSV. The plugs might be swapped with the CPR. That would make the motor run VERY rich! I would have those customers double-check the plugs. Or there is a problem with the wiring in the cold start circuit or the Thermo-Time switch is defective and the CSV is running all the time. Ask them if there is anything plugged into the hot start relay plug. There are all kinds of possibilities. On one car that was hard starting I found the "O" ring missing where the cold start valve attaches to the pipe. Sometimes the bolt holding the pipe is loose or one of the seals is missing. Once in a while I find the brass ring that holds the "O" ring in the bottom of the mixture unit dangling on the idle motor pipe. It is a difficult place to inspect which makes it all the more important to see what's going on under there. The point here is if the motor is not starting right there is a problem and you have to keep searching till you find it. I don't like replacing parts till I get lucky. I like to figure out what is wrong and then replace only the defective part. We are assuming the hard cold start problem is caused by the fuel system. A problem with the ignition can also cause hard cold starts.

[Ron]

I have had a few customers complaining of hard cold starts which they seem to find starting better with the CSV pulled. Hence their mixture seems to rich. One guy sent a video of his air plate which you could see bump up a little during his cold start. I wonder if that internal O-ring has anything to do with that cold start problems.
I wouldn't think so. If residual pressure from the WUR's return line can't get past the PPR's piston, it can't go anywhere, i.e., cause a rich condition.

Removing it wouldn't cause it to fail the rest pressure test, just shorten the time... The early style (pre-D) PPRs/FDs didn't have one. And I assume they found that fuel would weep between the piston and bore (?after wearing a while?), allowing pressure in the WUR's return line to drop. Whatever the reason, it was added for better residual pressure.

[Ron]

Ah I see what you mean.

I'm sure if someone was to take the time to remove that part, take measurements of the i/d, o/d and thickness of the o-ring and then get in touch with Arran at DeLoreanGo to provide that info, he could look to add that o-ring into the kit.

:histerical1:

[bytes311]

My return hose between the FD and the hard line to the tank was kinked pretty bad. I retested and Control Pressure stayed around 47 PSI, even with the additional shims in place.

60024 60026

My question now is, how do I separate this fitting from the hard line? It won't budge.

60025

If I can't remove it, could I pick up a fuel rated hose and some clamps and call it good? I have DPI's return line I would otherwise like to use, but if I can't get that fitting off...

[Ron]

Ah! That looks like the culprit.
I'm not familiar with the DPI line. Can you post a pic?

[bytes311]

Ah! That looks like the culprit.
I'm not familiar with the DPI line. Can you post a pic?

That had to be the issue all along. Especially now that I can shim the FD and it not affect the Control Pressure. :) I certainly appreciate all of your help, Ron. I really do.

This is DPI's return hose. It looks like it threads into the hard line, but I can't get the original fitting off. This is the low pressure side, right? So theoretically I could put a fuel rated rubber hose between the FD and the hard line using the original fittings?

60027 60028

[Ron]

Not sure, but it looks like the DPI would work as is, just doesn't have a bent pipe on the end?? I.E. remove everything from the FD on, including the bent pipe portion??

It is the "low pressure" side, BUT you need to use high pressure rated hose because regular fuel rated hose 's pressure rate is too low for the system. ...If you ever get a restriction down stream on the way to the tank, regular fuel rated hose will burst!

Sorry I didn't answer right back...A man wanted to buy my Silverado...:nana2:

[Delorean Industries]

Sometimes it can be a fight to remove the factory fitting from the compression sleeve as pictured. This will release if you carefully hold the back side of sleeve (where it is exposed) and rotate the fitting.

If you have any questions on the orientation of the lines at the distributor (double banjo fitting) reference pictures are available on the product page. If you have any other questions just let us know.

https://deloreanindustries.com/1-braided-stainless-fuel-injection-hose-small-line-set/

[bytes311]

Sometimes it can be a fight to remove the factory fitting from the compression sleeve as pictured. This will release if you carefully hold the back side of sleeve (where it is exposed) and rotate the fitting.

If you have any questions on the orientation of the lines at the distributor (double banjo fitting) reference pictures are available on the product page. If you have any other questions just let us know.

https://deloreanindustries.com/1-braided-stainless-fuel-injection-hose-small-line-set/

The fitting came off after doing exactly what you suggested. Thanks! The new braided hose is now installed.

Control Pressure was still acting weird last night. As soon as I blipped the throttle, it shot up from 47 PSI to 70 PSI and remained there. I confirmed the return line is completely free from blockage between the FD to the tank. I also remembered I added an extra shim to the PPR, so I removed it. Now Control Pressure is a constant 47 PSI.


I wouldn't think so. If residual pressure from the WUR's return line can't get past the PPR's piston, it can't go anywhere, i.e., cause a rich condition.

I think the extra shim put too much tension on the spring, enough so that the piston couldn't move to release residual pressure.

[Ron]

Control Pressure was still acting weird last night. As soon as I blipped the throttle, it shot up from 47 PSI to 70 PSI and remained there. I confirmed the return line is completely free from blockage between the FD to the tank. I also remembered I added an extra shim to the PPR, so I removed it. Now Control Pressure is a constant 47 PSI.
What did the Primary Pressure wind up being in the end?
If the Primary Pressure was ~70 PSI when the Control Pressure shot up to 70 PSI, you had a restriction/blockage. The 'rule' about them matching always applies -- Even if you added 2 or 3 extra shims, the Primary Pressure would skyrocket, but the control pressure should basically remain normal (49-55 PSI, warm).
I'd guess you disturbed some trash somehow while removing the extra shim...




I wouldn't think so. If residual pressure from the WUR's return line can't get past the PPR's piston, it can't go anywhere, i.e., cause a rich condition.I think the extra shim put too much tension on the spring, enough so that the piston couldn't move to release residual pressure.
Ignore that reply -- It was about a different o-ring than the one next to the shims and COLD starts.

...The number of shims determine how much System (Pump) Pressure is released to obtain Primary Pressure (and the WUR releases Primary Pressure to obtain Control Pressure).

[bytes311]

What did the Primary Pressure wind up being in the end?
If the Primary Pressure was ~70 PSI when the Control Pressure shot up to 70 PSI, you had a restriction/blockage. The 'rule' about them matching always applies -- Even if you added 2 or 3 extra shims, the Primary Pressure would skyrocket, but the control pressure should basically remain normal (49-55 PSI, warm).
I'd guess you disturbed some trash somehow while removing the extra shim...

PP and CP became the same after I blipped the throttle. I'm just not sure what it could be at this point other than there being a restriction inside the FD itself, or something related to the PPR. My WUR/CPR unit tested OK. The flow of fuel returning to the tank looks good. The jerrycan between the FD and hard line collected approx. a gallon worth of fuel in a minute and a half. Control Pressure is not affected at all if I leave the PPR alone with its original shim in place.

[Ron]

What is the CP and PP now?

[bytes311]

What is the CP and PP now?

CP is 47 PSI and PP is 67 PSI.

[Ron]

The amount of fuel going into the jerry can out of the FD return line doesn't tell us much here because it carries the fuel the PPR releases to get Primary Pressure (A LOT) and it carries the fuel from the WUR as well (relatively little).

Did you ever remove the WUR's return line at the FD end (and plug the FD hole ;-) then dump the loose end into a jerry can?

[bytes311]

The amount of fuel going into the jerry can out of the FD return line doesn't tell us much here because it carries the fuel the PPR releases to get Primary Pressure (A LOT) and it carries the fuel from the WUR as well (relatively little).

Did you ever remove the WUR's return line at the FD (and plug the FD hole ;-) then dump the loose end into a jerry can?

Shoot, good call. I forgot to do that. I'll do that tonight.

On another note, I just realized I have these two banjos (see arrow) to the FD backwards. They are both routed correctly, but not connected in the same order as the diagram. I can't imagine it being an issue but thought I'd ask.
60069

[Ron]

Right, swapping them wouldn't matter. That port, the port the WUR's return line goes to, and the PPR's chamber are all connected internally. This should give them all an unrestricted path to the tank via the FD's return line.

I don't have a guess as to how much fuel the WUR's return line should dump into a jerry can, other than "some". But if doing it gives you ~normal PP and CP, suspect trash in the FD's fuel return circuit... Maybe, remove everything from the 2 FD ports (above) and look closely for a piece of broken o-ring in the ports, PPR chamber, or the channels connecting them all together. (The tiny hole in the bottom of the FD port the WUR's return goes to would be my guess.)