What's it take to replace injectors and cold start valve?

[mluder]

I'm getting ready to replace my injectors and cold start valve. The workshop manual does not provide a procedure for this that I could find so it's either extremely simple or...

So how hard is it to do and what's the process?
Beyond the seals and clips what else do I need?
Will I need to replace the copper washers top and bottom where the fuel line attaches to the injector?

Cold Start Valve - Any special tips on this?

Any help would be great.

Steve

[jawn101]

Never reuse copper washers - not worth saving a few cents where atomised fuel is concerned.

[WelmoedJ]

In a nutshell:

- unlock the clips that hold the injectors in their seats.
- unscrew the banjo bolts atop of the injectors
- (as said previously) get rid of the old copper washers
- put a new copper washer on the banjo bolt
- put this combination through the bnjo's eye
- put a copper washer on the banjo bolt's end
- screw the banjo bot into the new injector and tighten
- do this six times ( :) )

For the cold start injector the process is somewhat the same.
- no clip to remove, but the casing with the blue connector with the injector in it.
- I haven't been in there but it seems to me:
two bolts to remove
1 O-ring (injector seal) to replace
2 copper washers to replace

Tip:
You can hand tighten the banjo bolts, but it depends on how strong your hand force is.
It seesm I have the proper torque in my fingers so my advice is: use your fingers while tightening the banjo bolts.
Up to now I haven't had a leaking washer using this method.

[David T]

Before replacing the injectors, consider having them cleaned and tested. The CSV (Cold Start Valve) does not need to be cleaned. It either works or it doesn't. Be careful overtorquing the "hollow" bolts. They can be broken. You should probably replace the rubber seals on the injectors. Order them along with the copper washers. The clips are reusable. Don't kink, stretch, or overtwist the fuel lines. When you are finished you should not have any smell of fuel whwn the motor is running. If you do, you have a small leak and you must find and fix it.
David Teitelbaum

[WelmoedJ]

Electrically operated injectors can be cleaned relatively easy.
Pressure operated are harder to clean, ultrasonic cleaning doesn't work for this type of injectors.
Important is a good spray pattern.

Injectors of cars that sat for quite a long time are often useless.
That's because the nozzle and seat get pitted with rust and therefore won't seal properly any more.

As testing also has to be paid for, consider how long your car sat.
Save the money for testing if the car sat way too long and put that money into new injectors.
You will save yourself a lot of agony.

[DMCMW Dave]

Why are you replacing the cold start valve? I don't believe I've ever seen one fail.

[David T]

I have cleaned many sets of injectors and so far have not had to throw any away. I suppose it is possible to have one that just won't clean up but that doesn't seem to be the case, at least not yet. If you send the injectors to a Delorean vender and they don't clean up you can try to negotiate away the cost of testing if you buy a new set from them. I am sure they will work with you. As for the CSV, I would make sure it is getting electric and a good ground. Any problems with the CSV are usually because of a wiring or Thermo-Time switch problem. Very easy to test, pull the CSV, stick it in a bottle and do the plug swap.
David Teitelbaum

[Nicholas R]

I've reused copper washers countless times and never once had an issue. There was a period of time when I was pulling my injectors every 500 miles or so to clean them so those washers got reused a LOT. Finally replaced the injectors and never had an issue since. I'd say those washers got re-used ~15 times or so and never once have I had an issue. I could see replacing your washers if they're 30 years old out of principle, but it's ridiculous to change them every time you disconnect a fuel line.

[LEVY]

Copper "washers" are not really washers, they are seals that are meant to compress to form a tight seal. You may reuse them but then you will need to use more torque to keep them from leaking, I would not recommend to be reused, yes it can be but not recommended.

LEVY

[mluder]

Before replacing the injectors, consider having them cleaned and tested. The CSV (Cold Start Valve) does not need to be cleaned. It either works or it doesn't. Be careful overtorquing the "hollow" bolts. They can be broken. You should probably replace the rubber seals on the injectors. Order them along with the copper washers. The clips are reusable. Don't kink, stretch, or overtwist the fuel lines. When you are finished you should not have any smell of fuel whwn the motor is running. If you do, you have a small leak and you must find and fix it.
David Teitelbaum

I have a terrible fuel smell right now - running rich - so if replacing the injectors clears that up I'll be exstatic.

S

[mluder]

Electrically operated injectors can be cleaned relatively easy.
Pressure operated are harder to clean, ultrasonic cleaning doesn't work for this type of injectors.
Important is a good spray pattern.

Injectors of cars that sat for quite a long time are often useless.
That's because the nozzle and seat get pitted with rust and therefore won't seal properly any more.

As testing also has to be paid for, consider how long your car sat.
Save the money for testing if the car sat way too long and put that money into new injectors.
You will save yourself a lot of agony.

My car sat for about 10 years. The PO spent a bunch to rehab the fuel system but stopped short of replacing the injectors. I'm hoping it will help to even out some inconsistancies in the idle and dwell and reduce the hydrocarbons so I can pass emissions. I think the old injectors are not sealing correctly and leaking fuel.

S

[mluder]

Why are you replacing the cold start valve? I don't believe I've ever seen one fail.

Having issues with cold starts. It takes 3-4 tries to catch. I haven't pulled it to test it yet but I figure if I'm going to remove it and have to replace seals etc to re-install, might as well have a replacement on hand to swap if it isn't squirting.

[mluder]

I have cleaned many sets of injectors and so far have not had to throw any away. I suppose it is possible to have one that just won't clean up but that doesn't seem to be the case, at least not yet. If you send the injectors to a Delorean vender and they don't clean up you can try to negotiate away the cost of testing if you buy a new set from them. I am sure they will work with you. As for the CSV, I would make sure it is getting electric and a good ground. Any problems with the CSV are usually because of a wiring or Thermo-Time switch problem. Very easy to test, pull the CSV, stick it in a bottle and do the plug swap.
David Teitelbaum

I checked the wiring on the CSV and Thermotime - both were very clean - no rust or corosion in the conections.

I haven't pulled the CSV to test - what do you mean by "plug swap"?

[DMCMW Dave]

I checked the wiring on the CSV and Thermotime - both were very clean - no rust or corosion in the conections.

I haven't pulled the CSV to test - what do you mean by "plug swap"?

Connect the grey plug that's on the regulator to the blue plug on the cold start injector. That supplies a constant 12V to the injector once the key is on. Crank the engine. If the injector sprays (aim it into a jar!) it works. If it doesn't, it's bad.

Don't leave the grey plug there, it will flood the engine terribly if you try and run it this way.

[manta147]

David T and Nicholas-How do you clean your injectors or do you send them out? Nicholas I imagine if you were cleaning them every 500 miles you had a system of cleaning them yourself?
Thanks in Advance,
Carter

[jawn101]

David T and Nicholas-How do you clean your injectors or do you send them out? Nicholas I imagine if you were cleaning them every 500 miles you had a system of cleaning them yourself?
Thanks in Advance,
Carter

The vendors can clean and spray test them for you, as can pretty much any shop you might have locally that has a Bosch sign out front or works with diesel engines :) I'm sure there are DIY ways but from what I've seen, there's no substitute for a trained eye when verifying the spray pattern.

[David T]

The only way I know to properly clean and test the injectors is with the injector cleaner/tester. You have a picture of it in your Workshop Manual. D:03:01. It is easy to see if the spray pattern is good, if it is bad you see it squirting jets of spray instead of atomizing the liquid into a cloud. The tester also checks the opening pressure. All of the Delorean venders have at least one. Any shop that works on Volvos should have one. You should not have to clean the injectors often. In a running car the fuel itself has cleaners in it to prevent and remove any deposits. I also reuse the copper seals but good practice is to replace them. They get work-hardened from being used and will not seal well. To soften (anneal) them you can heat them up and reuse them. In tough cases you can smear a little silicone sealer on them. The problems start when you reuse a copper seal without annealing it and it leaks. So you tighten the bolt a little. That doesn't stop the leak so you tighten it somemore. At some point in this process the hollow bolt breaks because you overtorqued it. That is why it is recommended to replace the seals. As for the hard cold start, you need to verify the cold start valve works using the plug swap and that it works when hooked up to the Thermo-time switch. It will only squirt when:
1) The ignition switch is on
2) The fuel pump has created enough pressure
3) The motor is cold
4) You have not tried to start the motor yet (the Thermo-time switch times out)
5) During cranking
It is not uncommon to see a wiring problem or a bad Thermo-time switch.
David Teitelbaum

[Nicholas R]

David T and Nicholas-How do you clean your injectors or do you send them out? Nicholas I imagine if you were cleaning them every 500 miles you had a system of cleaning them yourself?
Thanks in Advance,
Carter


The vendors can clean and spray test them for you, as can pretty much any shop you might have locally that has a Bosch sign out front or works with diesel engines :) I'm sure there are DIY ways but from what I've seen, there's no substitute for a trained eye when verifying the spray pattern.

You clean them using a sonic cleaner. It's pretty much the only way you can clean them. They're not too expensive. You can analyze the spray pattern using a bench tester. Those are harder to buy and easier to make. To make one you can use this paint pressure tank from harbor freight. If you replace it with a regulator that goes up to around 100psi, you can attach a fuel line with the right fittings and test injectors all day long. You can even adjust the regulator slowly increasing the pressure, while watching the gauge to see when the injectors crack and when they fan out.
http://www.harborfreight.com/media/catalog/product/cache/1/image/370x/9df78eab33525d08d6e5fb8d27136e95/i/m/image_11446.jpg

I dont have my own but Ken and Cliff here in Cincinnati both have one so I just use theirs.

[mluder]

As for the hard cold start, you need to verify the cold start valve works using the plug swap and that it works when hooked up to the Thermo-time switch. It will only squirt when:
1) The ignition switch is on
2) The fuel pump has created enough pressure
3) The motor is cold
4) You have not tried to start the motor yet (the Thermo-time switch times out)
5) During cranking
It is not uncommon to see a wiring problem or a bad Thermo-time switch.
David Teitelbaum

Here's what I know. When I turn the key after the engine has been cold for as little as an hour or so, it tries to start but doesn't fully catch. This is followed by 3 to 4 more key turns before it catches and even then it's tenuous so I have to pump the gas pedal to get it fired up. After it's running. if I turn it off and wait a minute or two it will start on the first turn. If I shut it down and wait 10 to 15 minutes (like after filling at the gas station) it's hard to start again but often only takes 2 attempts.

The fuel system was heavily worked over before I bought the car.
- Fuel system pressure and rest pressure were not to spec. The fuel pump assembly and associated pickup and return hoses were redone. Accumulator replaced. This leads me to believe that I'm maintaining pressure - i.e. fuel is not leaking back down from the system which is why I thought CSV.
- Not sure about the status of the thermotime switch - is there a way to test it's functionality?

Thanks in advance for your advice. I'd love to get this sorted. It's kind of embarrassing to have people say "cool car" or such when I'm getting in only to have to sit there and turn the key a bunch and hope it starts.

Steve

[nullset]

Here's what I know. When I turn the key after the engine has been cold for as little as an hour or so, it tries to start but doesn't fully catch. This is followed by 3 to 4 more key turns before it catches and even then it's tenuous so I have to pump the gas pedal to get it fired up. After it's running. if I turn it off and wait a minute or two it will start on the first turn. If I shut it down and wait 10 to 15 minutes (like after filling at the gas station) it's hard to start again but often only takes 2 attempts.


That doesn't sound like a problem with the CSV. The CSV should only fire when the engine is cold.

Pull your air box, jumper your RPM relay. Wait a few seconds. Push down on the pressure plate. Feel that resistance? Good. Now unjumper the relay, and see how long it holds that pressure. It should hold for at least half an hour or so, right?

When it's hard to start, try the plug swap (blue to grey). If it fires right up, your CSV is fine, but you have another problem. It could be the o-ring in the fuel distributor (PPR O ring I think it's called), since you've already replaced the accumulator.

--buddy

[nullset]

Side note….

If you do decide to replace the injectors, get the intake manifold O-ring and new copper washer sets, and take the time to remove the intake manifold and thoroughly clean and inspect everything.

You'd might as well replace spark plugs and wires while you're in there. That job is _much_ easier with the manifold out of the way.

--buddy

[mluder]

OK - I pulled the plug from the regulator and plugged it into the CSV. It fired on the first try.

I will check the pressure plate in the fuel distributer next. If it's not holding pressure there is that due to the o-ring in the distributer that you refer to?

Steve


That doesn't sound like a problem with the CSV. The CSV should only fire when the engine is cold.

Pull your air box, jumper your RPM relay. Wait a few seconds. Push down on the pressure plate. Feel that resistance? Good. Now unjumper the relay, and see how long it holds that pressure. It should hold for at least half an hour or so, right?

When it's hard to start, try the plug swap (blue to grey). If it fires right up, your CSV is fine, but you have another problem. It could be the o-ring in the fuel distributor (PPR O ring I think it's called), since you've already replaced the accumulator.

--buddy

[David T]

If it started right up with the plug swap when cold your cold start valve works. You have a problem either in the wiring of the CSV circuit or a bad Thermo-Time switch.

If you have a problem starting warm-hot you have a problem with the CPR and/or holding rest pressure. There are other systems that function during a cold/warm start. Among them include:
Vacuum advance
High idle
Warm air intake
Additional enrichment on the CPR
Ballast resistor bypass
They don't individually seem to have as large an effect on hard starting but if there is a combination of problems it can make it harder to start.
David Teitelbaum

[mluder]

It definately seems to be a problem with rest pressure.

I jumpered the RPM and ran the fuel pump - good pressure at the intake. When I shut down the fuel pump it had completely lost pressure within about 5 minutes.

I saw a way to test the thermotime switch somewhere in the forums. I will do that to make sure I don't have compounding issues.

Any advice on how to proceed with ruling out the rest of the list you mentioned?

I really appreciate it. - This cold start has been the bane of my exisitnace.

Steve


If it started right up with the plug swap when cold your cold start valve works. You have a problem either in the wiring of the CSV circuit or a bad Thermo-Time switch.

If you have a problem starting warm-hot you have a problem with the CPR and/or holding rest pressure. There are other systems that function during a cold/warm start. Among them include:
Vacuum advance
High idle
Warm air intake
Additional enrichment on the CPR
Ballast resistor bypass
They don't individually seem to have as large an effect on hard starting but if there is a combination of problems it can make it harder to start.
David Teitelbaum

[mluder]

Alright, now it also hard to hot start. 10 minutes with the engine off is enough to completely loose pressure?

Steve

[Bitsyncmaster]

Alright, now it also hard to hot start. 10 minutes with the engine off is enough to completely loose pressure?

Steve

If your still on the original accumulator, get it replaced first.

[mluder]

If your still on the original accumulator, get it replaced first.

I'm almost 100% certain it was replaced by the previous owner a few months before I bought the car as it had sat for 10 years and had to have alot of the fuel system re-built at DMCNW just to get it running.

[Bitsyncmaster]

I'm almost 100% certain it was replaced by the previous owner a few months before I bought the car as it had sat for 10 years and had to have alot of the fuel system re-built at DMCNW just to get it running.

I've seen them fail right out of the box. Now you need to find why your not holding rest pressure. Better pull the PPR O-ring and check it but I bet it's your accumulator since a bad one will only hold for about 5 min.

[mluder]

I've seen them fail right out of the box. Now you need to find why your not holding rest pressure. Better pull the PPR O-ring and check it but I bet it's your accumulator since a bad one will only hold for about 5 min.

OK - I'll do the accumulator.

Sorry, to be annoying - What/where is the PPR o-ring. Difficult to replace?

Steven

[Bitsyncmaster]

OK - I'll do the accumulator.

Sorry, to be annoying - What/where is the PPR o-ring. Difficult to replace?

Steven

Very simple job to check the PPR o-ring but sometimes it sticks inside and needs a little force. You remove that large "nut" on the front right side of the FD. Inside is a spring with shim washers pressing a "piston" inside the hole. That piston needs to come out and the o-ring is mounted on the other side of the piston.

BUT BE CARFUL YOU DON'T DROP ANYTHING DOWN IN THE VOD.

[mluder]

Very simple job to check the PPR o-ring but sometimes it sticks inside and needs a little force. You remove that large "nut" on the front right side of the FD. Inside is a spring with shim washers pressing a "piston" inside the hole. That piston needs to come out and the o-ring is mounted on the other side of the piston.

BUT BE CARFUL YOU DON'T DROP ANYTHING DOWN IN THE VOD.

And I suppose im just looking for deterioration in the o-ring? Cracks etc.?

[jawn101]

And I suppose im just looking for deterioration in the o-ring? Cracks etc.?

The seal must be absolutely perfect. It's easy to remove but not as easy to reinstall. From what I've read, even the slightest imperfection in either the o-ring itself or the surface it mates to will cause a bad seal and you'll have plenty of problems as a result. Search the forum for PPR and you'll find a ton of threads on the same topic. If you're not sure you can handle it, you might hold off until you can find someone who can. I know I'd be apprehensive about attempting it unsupervised and I've had pretty much the whole car apart.

As always, Hervey's images prove an invaluable source of information:
http://www.specialtauto.com/delorean-parts/images/fuel-prim-pressure-reg-plun.jpg

http://www.specialtauto.com/delorean-parts/images/Prim-press-regulator-1.jpg

http://www.specialtauto.com/delorean-parts/images/pressureregulator.jpg

[DMCMW Dave]

Flat is not really a problem. If you inspect it and it looks like someone took a bite out of it, it's bad. And relatively obvious.

[mluder]

The seal must be absolutely perfect. It's easy to remove but not as easy to reinstall. From what I've read, even the slightest imperfection in either the o-ring itself or the surface it mates to will cause a bad seal and you'll have plenty of problems as a result. Search the forum for PPR and you'll find a ton of threads on the same topic. If you're not sure you can handle it, you might hold off until you can find someone who can. I know I'd be apprehensive about attempting it unsupervised and I've had pretty much the whole car apart.

As always, Hervey's images prove an invaluable source of information:
http://www.specialtauto.com/delorean-parts/images/fuel-prim-pressure-reg-plun.jpg

http://www.specialtauto.com/delorean-parts/images/Prim-press-regulator-1.jpg

http://www.specialtauto.com/delorean-parts/images/pressureregulator.jpg

Thanks - this is perfect. Once again - you guys on this board have prooven to be an invaluable asset. I'll try to take a look at it tonight.

Is the o-ring pretty standard - NAPA, Auto Zone, etc or only available from the DeLorean vendors?

Is there any way to test the accumulator or is it a swap and see if it makes a difference?

Steve

[Bitsyncmaster]

The O-ring is a metric size and needs to be the correct one.

If you can pull the return line from the accumulator then you can test if it leaks. You would need to put the return (the low pressure overflow) line into a jar, jumper your RPM relay to pressurize the system. Then you can shut off the pump and see if any fuel accumulates in the jar. If not, then you have a leak elsewhere.

[DMCMW Dave]

If you can pull the return line from the accumulator then you can test if it leaks. You would need to put the return (the low pressure overflow) line into a jar, jumper your RPM relay to pressurize the system. Then you can shut off the pump and see if any fuel accumulates in the jar. If not, then you have a leak elsewhere.

A bit more detail - pull the hose off the rear end of the accumulator. Plug it. Put another hose on the accumulator and direct it into a jar. Either run the car or jumper the pump. You may get a short surge of fuel out of the accumulator as it pressurizes but it should stop. If you get a constant trickle the accumulator has failed internally.

[mluder]

Well, maybe I'll pull the PPR and take the whole thing to NAPA and see if they have a way to size it.

Gonna have to look into the accumulator problem and will try your test. I assume a bad accumulator will affect hot starts as well as cold starts cause once fuel has backed out of the system, whether it happens in five minutes or 5 hours, its not going to start on the first try.

Thanks again guys - I'm more of a woodworker/builder by nature but good with my hands though I'm new to this mechanic thing. Most I had ever done was change the oil or flat tire so basic engine theory escapes me. That said, I'm learning more and more every day. The manual is helpful but people like you are oftne more so. I appreciate it.

Steve

[mluder]

So I replaced the o-ring on the PPR. Just took the whole thing to the local auto parts store and we matched it by eye. Installed the new one and buttoned everything back up. It now starts on the first turn every time - even 24 hours later. I haven't tried a hot start yet so that remains to be seen.

I may still check the accumulator but it seems that it may be working just fine.

Injectors will be next weekend. Hopefully that will even out the fuel distribution enough and with a new catalytic convertor installed I can pass emmisions and get regular daily driver plates.

Thanks again for the help guys. I owe you much pizza and beers - or the beverage of your choice.

[jawn101]

...or the beverage of your choice.

Apparently that's been voted as Cheerwine. :)

[mluder]

Apparently that's been voted as Cheerwine. :)

Rumir has it it's available in a few local groceries although it's tradiutionally a southern thing, right?

[jawn101]

Rumir has it it's available in a few local groceries although it's tradiutionally a southern thing, right?

Seems to be, but I found it in a small northern CA supermarket chain called Nugget. But they specialize in gourmet and hard to find things.

[bluscreen]

Connect the grey plug that's on the regulator to the blue plug on the cold start injector. That supplies a constant 12V to the injector once the key is on. Crank the engine. If the injector sprays (aim it into a jar!) it works. If it doesn't, it's bad.

Don't leave the grey plug there, it will flood the engine terribly if you try and run it this way.

If it's bad, you recommend a new CSV?
Mine's getting power, but doesn't spray. When I swap plugs I can "feel" it trying, but nothing is coming out.

[WelmoedJ]

If it's bad, you recommend a new CSV?
Mine's getting power, but doesn't spray. When I swap plugs I can "feel" it trying, but nothing is coming out.

Disconnect the injector from the fuel line and see if it "pisses".
If it does, it's the injector (clogged or stuck closed), if it doesn't it's the fuel distributor not performing as it should.

The latter can be caused for different reasons:
- No supply to the FD (check the feed line, CPR line to the FD)
- Stuck or clogged valve inside FD
- Bad PPR (primary pressure regulator)

[bluscreen]

Disconnect the injector from the fuel line and see if it "pisses".
If it does, it's the injector (clogged or stuck closed), if it doesn't it's the fuel distributor not performing as it should.

The latter can be caused for different reasons:
- No supply to the FD (check the feed line, CPR line to the FD)
- Stuck or clogged valve inside FD
- Bad PPR (primary pressure regulator)

Thanks for your help, Welmoed! Noted for sure. Thank goodness the problem wasn't a stuck/clogged valve inside the FD (or issue with the PPR for that matter).

I'm not saying this DID happen, but it's possible that last night I found the inertia switch was inadvertently triggered. :hihi2: