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

[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.
CPR pressure range.JPG

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.
CPR pressure range.JPG

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.

wur.jpg

Fuel Distributor is 0 438 100 076, which I believe is a Volvo unit. 20190508_065135.jpg

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.
cpr_model_number.jpg

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.
cpr_model_number.jpg

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. 20190508_065153.jpg

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:

PPR_s.jpg

[Ron]

Mine or the picture above? Mine has vacuum ports on either side. 20190508_065153.jpg

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!!!