HELP: D won't start without starter fluid

[FireProofCane]

First, my apologies if this is posted in the wrong place, feel free to move it. Hey guys, I'm new here but I've had my Delorean for about 6 months and have done a TON of reading about these things. The car I bought was in excellent condition, all original, and 27k miles, but had not been running for 2-3 years. The car ran out of gas and was then parked in a garage and ignored. When I got the car, the fuel pump needed to be replaced (some rust do to moisture in totally drained fuel system. Anyway, long story short I have done the following:

- Replaced the fuel pump and filter
- Tested CSV by doing plug swap (car will actually idle with plug swap for a little while before flooding).
- Tested TTS by testing OHM's

I can crank the car by spraying starter fluid into the intake. After it cranks, if I keep my foot on the gas and the engine about 3500 RPM's, the car will keep running. But as soon as I let off the gas, or the engine drops below 3k RPM's, I can't recover and the engine just dies. Then I need starter fluid to crank again.

After all my reading and playing around, I feel like I might have a air flow adjustment problem or (and maybe more likely) I may have a fuel mixture problem. I know fuel is coming out of the injectors because if I put one in a mason jar and attempt to crank the car the injector is spraying fuel.

So, in a couple hours I am about to start messing with the fuel mixture screw but I was looking for any other input/ideas before I did.

[Bitsyncmaster]

My CSV had a bad wire (crimp) on one of the bulkhead connectors and would never fire. You need to verify your CSV sprays with a cold engine start putting it in a jar and cranking the engine.

You probably have a miss adjusted mixture for your other problem needing to hold high RPMs.

[bytes311]

First, my apologies if this is posted in the wrong place, feel free to move it. Hey guys, I'm new here but I've had my Delorean for about 6 months and have done a TON of reading about these things. The car I bought was in excellent condition, all original, and 27k miles, but had not been running for 2-3 years. The car ran out of gas and was then parked in a garage and ignored. When I got the car, the fuel pump needed to be replaced (some rust do to moisture in totally drained fuel system. Anyway, long story short I have done the following:

- Replaced the fuel pump and filter
- Tested CSV by doing plug swap (car will actually idle with plug swap for a little while before flooding).
- Tested TTS by testing OHM's

I can crank the car by spraying starter fluid into the intake. After it cranks, if I keep my foot on the gas and the engine about 3500 RPM's, the car will keep running. But as soon as I let off the gas, or the engine drops below 3k RPM's, I can't recover and the engine just dies. Then I need starter fluid to crank again.

After all my reading and playing around, I feel like I might have a air flow adjustment problem or (and maybe more likely) I may have a fuel mixture problem. I know fuel is coming out of the injectors because if I put one in a mason jar and attempt to crank the car the injector is spraying fuel.

So, in a couple hours I am about to start messing with the fuel mixture screw but I was looking for any other input/ideas before I did.

I had the same problem with my car where if I let my foot off the gas the engine would just die. Turns out the plunger inside the fuel distributor had seized up. Do you feel any back pressure when you press down on the air plate?

[DMC-81]

Welcome and congrats on the purchase. Based on your situation, I think you are on the right track with the fuel metering system. I would pull a six injectors and do a full mason jar test to verify approximate amounts and spray pattern of each injector. The wisdom here is to touch the mixture screw last, after verifying every other component of the fuel system.

[FireProofCane]

I had the same problem with my car where if I let my foot off the gas the engine would just die. Turns out the plunger inside the fuel distributor had seized up. Do you feel any back pressure when you press down on the air plate?

When the car is running or off? Cause I can't keep it running. But when the car is not running, no I don't really feel any back pressure when I push the air plate down. Of course, I'm not really sure what it's supposed to feel like.

[FireProofCane]

Welcome and congrats on the purchase. Based on your situation, I think you are on the right track with the fuel metering system. I would pull a six injectors and do a full mason jar test to verify approximate amounts and spray pattern of each injector. The wisdom here is to touch the mixture screw last, after verifying every other component of the fuel system.

Thank you. I might try that. I have pulled 2 just to be sure and I figured the car running at higher RPM's without skipping or sputtering that it was spraying fine.

[Bitsyncmaster]

When the car is running or off? Cause I can't keep it running. But when the car is not running, no I don't really feel any back pressure when I push the air plate down. Of course, I'm not really sure what it's supposed to feel like.

Get to know what it feels like in the morning before you start it. It should almost bounce on it's own (no pressure at all to move it).

Then after you prime the system (try starting) you should feel a little pressure and know the difference.

[David T]

My guess is the fuel injectors (all of them) need to be pulled, cleaned and tested. Make sure the frequency valve (the thing bolted to the R/H valve cover with 2 hoses and a wire going to it) is buzzing. Make sure there is a plug in the housing over the mixture screw to seal up the vacuum.

[DMC5180]

When the car is running or off? Cause I can't keep it running. But when the car is not running, no I don't really feel any back pressure when I push the air plate down. Of course, I'm not really sure what it's supposed to feel like.

jumper the Rpm relay to run the fuel pump. You don't need the engine running. however if it is a stuck plunger situation, you will want to pull All the injectors and place them in jars first, so you don't accidentally pour fuel into the cylinders. If the plunger is stuck the fuel will fill the jars quickly. Do not Run the fuel bump more than 5 seconds without checking the jars. It all depends on the size of the jars you use though. I use baby food jars. The larger the jars the longer you can run the pump without over filling.

Do not mess with the mixture screw. it is unlikely to be the root cause of your running condition.

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[FireProofCane]

Get to know what it feels like in the morning before you start it. It should almost bounce on it's own (no pressure at all to move it).

Then after you prime the system (try starting) you should feel a little pressure and know the difference.

Yea, I don't think there is any difference. It seems like it moves exactly the same way. So does that imply a stuck plunger in the fuel distributed? Based on how nasty the fuel was when I started this process, I wouldn't be surprised if it gunked something up. What are my possible solutions?

[FireProofCane]

My guess is the fuel injectors (all of them) need to be pulled, cleaned and tested. Make sure the frequency valve (the thing bolted to the R/H valve cover with 2 hoses and a wire going to it) is buzzing. Make sure there is a plug in the housing over the mixture screw to seal up the vacuum.

There is no plug, I can drop the 3mm wrench in there without removing a plug. Could that vacuum leak be my problem or part of it? Would that plug missing cause the same symptoms as a ceased up plunger?

[Jonathan]

There is no plug, I can drop the 3mm wrench in there without removing a plug. Could that vacuum leak be my problem or part of it?

Part of the problem, yes. Not the whole problem though.


Would that plug missing cause the same symptoms as a seized up plunger?

No. A vacuum leak from a missing plug will cause idle hunt, but not what you're seeing with the engine ceasing to run without starter fluid.

... although, find something to plug that hole with and then see if you notice any changes. You can use a golf tee or piece of bubble gum for now, it's only temporary until you get something more appropriate.

Perhaps you should take a bunch of photos of your engine bay and post them here as there might be other things out of sorts you aren't realizing, and someone on here might spot them for you.

[FireProofCane]

My guess is the fuel injectors (all of them) need to be pulled, cleaned and tested. Make sure the frequency valve (the thing bolted to the R/H valve cover with 2 hoses and a wire going to it) is buzzing. Make sure there is a plug in the housing over the mixture screw to seal up the vacuum.

When should I hear the frequency valve running? When the car is in the "on" position or when the car is running? When the car is in the "on" position I do hear a humming sound from the engine bay but it doesn't sound like it's coming from the frequency valve.

[FireProofCane]

Part of the problem, yes. Not the whole problem though.



No. A vacuum leak from a missing plug will cause idle hunt, but not what you're seeing with the engine ceasing to run without starter fluid.

... although, find something to plug that hole with and then see if you notice any changes. You can use a golf tee or piece of bubble gum for now, it's only temporary until you get something more appropriate.

Perhaps you should take a bunch of photos of your engine bay and post them here as there might be other things out of sorts you aren't realizing, and someone on here might spot them for you.


Thank you, I'll try to get some pictures today. I used a golf tee but it didn't seem to cause much of a change.

[DMC5180]

the FV only runs when the engine is running.


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[FireProofCane]

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[David T]

Try disconnecting and reconnecting the plug to the frequency valve a couple of times. Sometimes a little corrosion is all it takes to keep it from working. If the frequency valve is not working the motor would run too lean. If there is no plug over the mixture screw the motor would run too lean. The combination would be so bad the motor won't run at idle. You probably also have other vacuum leaks making it even leaner. You also have all of the usual stale fuel system problems like:
Stuck fuel plunger
Plugged up/dirty/bad spray pattern injectors
Old, hard, leaky injector seals
Probably a bad CPR so it runs badly til it warms up.
Point is you have to go over the whole fuel system to get the motor to run well, not one thing at a time. The best place to start is the fuel tank. Empty it and wipe it out with Acetone. Reassemble the fuel pump and then replace the fuel filter.

[DMC5180]

just looking for things out of normal. I see an extra Ground wire (middle) in the cluster on the Intake manifold next to the ISM. track down where it goes to make sure it's a legitmate ground and not a PO work a round. I also see New wires spiced into the CS injector connector and CPR connector. Did you do that or a PO?


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[FireProofCane]

just looking for things out of normal. I see an extra Ground wire (middle) in the cluster on the Intake manifold next to the ISM. track down where it goes to make sure it's a legitmate ground and not a PO work a round. I also see New wires spiced into the CS injector connector and CPR connector. Did you do that or a PO?


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Thanks, yes I did that. Those connectors/wires were not in good shape. I've tested now to be sure the splice and connection is good. I'll check on that extra ground.

[Jonathan]

Here's a couple more electrical things to double check:

You can see both of these two items in your 5th picture.

The first is the pair of connectors that are used with the full throttle switches. Your car appears to be a manual transmission, so you only need one of them connected. The one that should be connected (I'm talking on the car's wiring harness side) on a manual trans car is the one with the pair of wires which is black for the ground wire and light green for the other wire. The connector you DON'T use on a manual trans car is the pair with the LGG wire (which means light green/green). This wire is for the automatic trans kickdown mode. They will look similar until you see them side by side. Basically the one you don't want has two shades of green (striped) and the one you do want to use is a solid green. Could be that someone plugged the wrong connector in for you (it is those white connectors that look like Tetris puzzle pieces).

The other thing to check on is the ground wire for the O2 sensor. You can see it in the area of the frequency valve and it is a red wire. It has a quick connect on it. The one end is screwed down and into the block and the other end uses that quick connector to attach to what goes to the O2 sensor and becomes the ground reference. I've attached a picture from my own car where you can see a red arrow indicating where it is supposed to be fastened to (mine is attached slightly above as the intended threaded hole was no good). Don't tug too hard on the connector end, but make sure it is still plugged in.

52369

[bfloyd]

When it starts using starter fluid... how long does it stay running?

2 years ago when I rebuilt my car, I too replaced the fuel pump with the new DMCH fuel pump / fuel sender combo unit. I could get the engine to start with starter fluid, but as soon as the starter fluid burned off it died. In my haste to get the car running, I accidentally installed the check valve in the fuel line at the pump backwards. With the check valve backwards, it wouldn't let gas get past the valve. Once I reversed it, it worked. It did run rough at first, but a little trial and error with the 3mm allen wrench in the air metering box fixed that right up.

Check your fuel connections carefully, and verify that the check valve is installed in the correct orientation.

[FireProofCane]

Try disconnecting and reconnecting the plug to the frequency valve a couple of times. Sometimes a little corrosion is all it takes to keep it from working. If the frequency valve is not working the motor would run too lean. If there is no plug over the mixture screw the motor would run too lean. The combination would be so bad the motor won't run at idle. You probably also have other vacuum leaks making it even leaner. You also have all of the usual stale fuel system problems like:
Stuck fuel plunger
Plugged up/dirty/bad spray pattern injectors
Old, hard, leaky injector seals
Probably a bad CPR so it runs badly til it warms up.
Point is you have to go over the whole fuel system to get the motor to run well, not one thing at a time. The best place to start is the fuel tank. Empty it and wipe it out with Acetone. Reassemble the fuel pump and then replace the fuel filter.

Thank you, this is good info on the car running lean. When I get a second hand over to help me with the car I will check to see if the frequency valve is running. Then tackle those other potential issues.

[FireProofCane]

Here's a couple more electrical things to double check:

You can see both of these two items in your 5th picture.

The first is the pair of connectors that are used with the full throttle switches. Your car appears to be a manual transmission, so you only need one of them connected. The one that should be connected (I'm talking on the car's wiring harness side) on a manual trans car is the one with the pair of wires which is black for the ground wire and light green for the other wire. The connector you DON'T use on a manual trans car is the pair with the LGG wire (which means light green/green). This wire is for the automatic trans kickdown mode. They will look similar until you see them side by side. Basically the one you don't want has two shades of green (striped) and the one you do want to use is a solid green. Could be that someone plugged the wrong connector in for you (it is those white connectors that look like Tetris puzzle pieces).

The other thing to check on is the ground wire for the O2 sensor. You can see it in the area of the frequency valve and it is a red wire. It has a quick connect on it. The one end is screwed down and into the block and the other end uses that quick connector to attach to what goes to the O2 sensor and becomes the ground reference. I've attached a picture from my own car where you can see a red arrow indicating where it is supposed to be fastened to (mine is attached slightly above as the intended threaded hole was no good). Don't tug too hard on the connector end, but make sure it is still plugged in.

52369



Thank you, I'll check on the connectors tonight.

[FireProofCane]

When it starts using starter fluid... how long does it stay running?

2 years ago when I rebuilt my car, I too replaced the fuel pump with the new DMCH fuel pump / fuel sender combo unit. I could get the engine to start with starter fluid, but as soon as the starter fluid burned off it died. In my haste to get the car running, I accidentally installed the check valve in the fuel line at the pump backwards. With the check valve backwards, it wouldn't let gas get past the valve. Once I reversed it, it worked. It did run rough at first, but a little trial and error with the 3mm allen wrench in the air metering box fixed that right up.

Check your fuel connections carefully, and verify that the check valve is installed in the correct orientation.

As long as I keep my foot on the gas, the car will stay running above 3k RPM's for as long as I want. As soon as I let my foot off the gas, it dies.

[Jonathan]

As long as I keep my foot on the gas, the car will stay running above 3k RPM's for as long as I want. As soon as I let my foot off the gas, it dies.

Generally speaking, this tells us the idle system is not taking over when it should. For one reason or another, when you aren't holding the throttle manually, the engine stops getting fuel, air or spark... or any or all of those three in combination.

[opethmike]

Shot in the dark here, but WAY back when I still had K-Jet I had a similar issue; the car would only start and run if I held the throttle open (right around 3,000 RPM). Turned out that the piping from the idle speed motor into the mixture unit had come out of the mixture unit.

To check for that:

Take the air filter housing off of the mixture unit
Close the garage door so it is dark in the garage
Shine a flashlight at where the copper pipe from the idle speed motor goes into the mixture unit body
Gently (GENTLY!) press down on the mixture unit plate, and look for the light of the flashlight shining in

If you can see the light, then the pipe or its o-ring & seal has come unseated.

[lazabby]

Here's a couple more electrical things to double check:

The other thing to check on is the ground wire for the O2 sensor. You can see it in the area of the frequency valve and it is a red wire. It has a quick connect on it. The one end is screwed down and into the block and the other end uses that quick connector to attach to what goes to the O2 sensor and becomes the ground reference. I've attached a picture from my own car where you can see a red arrow indicating where it is supposed to be fastened to (mine is attached slightly above as the intended threaded hole was no good). Don't tug too hard on the connector end, but make sure it is still plugged in.

52369

Where is the red wire located that is a ground for the O2 sensor. I was with another Delorean owner a few days ago and noticed that there were no wires connected to the right hand side. He couldn't remember what was suppose to be grounded there but was pretty sure there should be something. Perhaps it's the O2 sensor. I don't recall seeing any loose wired in the back of the engine that are red.

[Jonathan]

Where is the red wire located that is a ground for the O2 sensor. I was with another Delorean owner a few days ago and noticed that there were no wires connected to the right hand side. He couldn't remember what was suppose to be grounded there but was pretty sure there should be something. Perhaps it's the O2 sensor. I don't recall seeing any loose wired in the back of the engine that are red.

It is the red wire just above my red arrow (in the photo I attached). I had put that red arrow where it is to show where that ground is supposed to be screwed into the block. I moved mine a little away because I had a snapped off screw chunk in the proper hole. It is really just about two or three inches of that ground wire that has the red wrap on it. It has one of those typical black quick connects on it that then plugs into an opposed end that eventually leads to the ECU box connector behind the driver's seat. I don't have the drawings in front of me at the moment to look up the specifics though...

[FireProofCane]

Just wanted to thank everyone for their help. I'm not letting this thread die but I'm out of town on vacation for a week. I will be getting my hands dirty again when I get back and I'll let you all know what I find. Thanks again!