Cold Start Problem--Won't wake from 23 year nap.

[Dr.D]

Hello all!

I've been following this forum for several years. I became a Delorean owner about 16 months ago but have never driven my car!

My project: VIN 10144 was last registered in Rhode Island in 1995 and sat in a barn for 22 years until I purchased it and shipped it out to northern CA to do a frame off restoration. I promise I'll post all of the photos and story of the 16 month long project eventually. Suffice it to say that I took the car all apart down to the bare frame, did a lot of cutting and grinding and then learned how to weld in the new pieces.

I took the engine down to the block. I didn't touch the internals but replaced all of the seals/gaskets, etc. I did a leak down test before taking it apart and the engine checked out. As far as mechanicals, I've redone the cooling system (pump, radiator, hoses, etc.), I had the fuel system rehab'd by John Hervey, cleaned out the tank and have all new lines. The fuel pump was replaced by the PO prior to selling so that is the only thing I didn't have to replace.

I have all new plugs, wires, cap, rotor, etc and have the Flamethrower coil installed. (I have tried starting it with the original coil too, same results.)

The starter solenoid was corroded so I replaced the starter with the Eagle Premier starter. The car cranks nicely.

I have been trying to get the car started for a few weeks and just can't get it to fire up. Here's what I've done/checked.

There seems to be good fuel pressure, I can smell gas when I crank for a bit. The flapper gives good resistance, I can hear the pump going. The RPM relay was shot initially but I've replaced it. I've tried plugging the pressure regulator wire into the CSV but that doesn't help either.

I've checked the voltages at the coil. There is about 6 volts at the + side and about 1.5 volts at the - side. When I run a wire from the coil to the ground I get a spark but I don't think it's quite 12mm like the book says. When I run a wire from the jumper post to the + side of the coil, it doesn't help.

I checked the voltages at the resistor when cranking and it falls to 0 volts as the book says it should.

Since I had the whole engine out and apart, I THINK I put it all back right with the right connectors in the right places but obviously if I knew what was wrong, I wouldn't be posting this.

Here are the weird things I've found:

1. The "battery" light is on even with the key off. I searched for this problem and the best answer is that the voltage regulator on the alternator is shot. That still doesn't explain why the light would be lit with the key off and out of the car. Makes me think there is a short somewhere. The light stays on even when I tried disconnecting the Main Relay and then the Auxiliary Relay. When I unplug the brown wire from the alternator, the light goes off. I haven't bench tested the alternator. I think I'll likely upgrade the alternator after I get the engine running as I am probably going to put a stereo and external amp in the car and will want more "juice."

2. I got a new fuel sender from John Hervey. With about 10 gals in the tank, the needle is pointing at 12 O'clock and the low fuel light is on (when the car is in the "on" position, not when the key is off.)

3. With the key in the on position, if I turn on the head lights or flash the brights, there is a buzzing noise coming from the engine compartment. I believe I have localized it to the distributor. I also hear the same sound sometimes when I am cranking the car as I let off the key. In both instances, the buzzing only lasts about 1/2 to 1 second. It is NOT constant. I figured out that if I unplug the connector to the distributor (that connects to the ECU) the buzzing doesn't happen. Does this indicate a bad pulse coil in the distributor?

4. Several other electrical things don't work but I figured that was just corrosion and things to tackle in the future. For example, the horns don't work, but I have replaced both horns.

Also just FYI. In addition to the RPM relay, I did the relay upgrade/replacements as well as all of the fuses. The fuse box seems stock, in good order and non-melted. I have cleaned all of the connectors as best as I could but still haven't gotten the engine to catch. I tried starter fluid before I replaced the RPM relay and there was a brief sputter but never anything that I would call "internal combustion."

If any of you Delorean experts have suggestions about what to do next, I'd love to hear them. Is my next step replacing the pulse coil?

Thanks!

[David T]

You didn't say it but if you took the heads off and did not time the cams properly, that *could* be your problem. Do a compression test. If you have spark try some Ether and see if you get any pops. The alt light is curious but should not prevent you from starting. Could be a blown regulator or just a misplaced wire. If you are getting spark the impulse coil and the ignition ECU are functioning. Verify firing order, and put the stock coil back.

[Dr.D]

You didn't say it but if you took the heads off and did not time the cams properly, that *could* be your problem. Do a compression test. If you have spark try some Ether and see if you get any pops. The alt light is curious but should not prevent you from starting. Could be a blown regulator or just a misplaced wire. If you are getting spark the impulse coil and the ignition ECU are functioning. Verify firing order, and put the stock coil back.

I did NOT take off the heads. The engine is fairly low mileage (25K ish) so I didn't see the need. Just put all new gaskets and seals. I didn't touch the head gasket since the leak down test didn't indicate any leak at the valves, rings or into the coolant, oil, etc.

When I sprayed ether I do get a "pop" but I was expecting more of a brief firing of a few cylinders, and and the car to crank for a second or two. I have swapped the original coil back and forth a few times with the same result but the original seems to check out so I can put it back and stick with it for now. I did verify that the plug wires were hooked up in the right order and seated properly. The buzzing from the distributor (or maybe the vacuum advance valve?) puzzles/concerns me.

I am definitely getting spark when I run a wire from the coil to ground and crank but I'd guess its about 6-7 mm and not the 12mm that the manual specifies.

Drew

[Ron]

With everything hooked up normal, is the brilliance of the light the same with key on or off?

[Dr.D]

With everything hooked up normal, is the brilliance of the light the same with key on or off?

I you are referring to the "Battery" light, yes it is fully lit with the key off, in the ACC mode or switched to "run." I haven't noticed a difference in how bright the light is in the different positions.

[Ron]

I you are referring to the "Battery" light, yes it is fully lit with the key off, in the ACC mode or switched to "run." I haven't noticed a difference in how bright the light is in the different positions.
Yes.

Normally, when the key is ON, the bulb is fed 12V (Green wire) and grounded via the field circuit (Brown/Yellow wire>>regulator>>rotor>>ground). So the bulb lights. When the engine starts, the alternator outputs causing the field circuit to go to 12V. The bulb then has 12V on both sides and goes out.
[Circuit test: With the key on, engine off, and Brown/Yellow wire disconnected from the alternator, the bulb should not light. Ground the wire and the bulb should light.]

When the key is OFF, the bulb is not fed the 12V. If the regulator/alternator itself has shorted the field circuit to 12V (bad diode trio, if equipped; bad rectifier, etc.), current will flow 'backwards' through the field circuit>>bulb>>other devices fed by the Green wire (eg oil senders). These other devices will supply ground, so the bulb lights (or blows like a fuse). It's a fairly common failure. Usually, the light will glow if it is the regulator/trio, and burn normal/bright if it is in the alternator itself.

I suggest you address this first. This type of short can introduce AC into the other circuits (when the alternator is trying to put out) and make them act up. I'd remove the alternator and have it checked at an auto parts.
...It would probably still start, but you might kill several birds with one stone.

=====

Pull several of the easy plug wires to see if the spark is getting to their plug end. Use a grounded spare spark plug...If all ok, the pulse coil and the rest of the ignition parts are probably ok.

Once you fix the starting problem, you may not know it due to flooding...

[Jonathan]

Personally, I would tackle some of these electrical problems you've mentioned first. You say they might just be corrosion and you'll get to them later, but as Ron mentioned, these electrical connections or cross-ups might be contributing to more of the engine firing problem than you thought.

The fuel sender problem sounds like it isn't plugged in. The needle pointing straight up is the default "fail" mode. Not sure about the low light if it isn't getting a signal. Double check the connections on the top of the sender and the short piece of wiring harness. The issue could be in the instrument cluster though. Have you had that out or inspected/repaired? It might have something to do with your battery light or it may not.

Similar with the horns. That's a pretty easy circuit and while it could wait until later, it might teach you something about what is going on if you trace it out and find the problem.

Does the air plate "bounce" freely after you've let the car sit for enough time for the fuel pressure to go away? You said you felt good resistance at that plate assuming it was fuel pressure and all I thought was maybe it's not resistance from the fuel pressure but it's a sticky plunger.

That buzzing might be coming from your frequency valve, which it generally is supposed to do. How's your frequency valve look?

[powerline84]

One of the ignition problems on my car when I put the new motor in was the 12 volt signal to the distributor had been discovered to be chewed by mice. Distributor was also one tooth off. Replaced the wire , and pulled distributor motor Fired right up.

[Dr.D]

OK. I have solved a lot of the issues. The alternator light staying on was my mistake. I had hooked the Brown wire up to the wrong tab on the alternator. Now it functions properly and only comes on when the key is in the run position (and not running). The fuel gauge issue was also my bad, the Hervey sender doesn't have a "direction" to plug it in. I had it backwards. Now it works fine.

So back to the cold start issue. I got a new stock coil and installed it. Still didn't fire. I went through each connector at the ballast resistor and coil and cleaned each one carefully with both electronic contact cleaner and vinegar on a nylon brush. Then I crimped them all down really tight. Still would crank but not fire.

Then I just had an accidental discovery.......If I try to start it with the RPM relay in and then take it out and try again, the car will start up and roar to life for about 2-3 seconds and then die (since the fuel pump isn't running). The same thing happens if I jumper the pins on the RPM relay for a few seconds and then pull out the jumper. The car will fire right up for 2-3 seconds and then die (from lack of fuel).

I don't know if the mixture is way off with the RPM relay in or the relay jumpered, then it won't start. But it will start briefly with the relay and/or jumper out. That doesn't make sense to me but I think it's getting close. At least I heard what my engine sounds like albeit briefly. I also seem to have solved my spark issues.....

Any ideas.

[David T]

Are you sure you are pulling the RPM relay? Jumper it so the pump runs continuously and see if the motor will run for more than a few seconds.

[Dr.D]

Yes I am sure it is the RPM. I recently replaced it. When I jumper it, I hear the pump going continuously. It won’t start. Then I pull the jumper and it does.

Could I have one of the fuel lines hooked up wrong so that when the pump is going the pressure on a return line obstructs fuel flow?

I just watched the old K-jet video last night and there were so many check valves in the system that I was wondering..,,


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[opethmike]

Here is a useful reference you can compare your fuel line routing to:

https://delorean.co.nz/mydmc/wp-content/uploads/2017/02/Fuel-Pipe-Hose-Route.jpg

[Ron]

I could see it doing that if the CSV line was swapped with the small WUR/CPR line (going to the Fuel Distributor).

If the lines check out, does it run for 2-3 seconds after installing then removing the relay/jumper every time, basically?

After it ran the 2-3 seconds:
Did you try to get it running and/or keep it running with starting fluid?...while the relay/jumper was removed?

[SS Spoiler]

My new DMCH fuel pump got hooked up
backwards and had similar issues....

[Dr.D]

That diagram looks very helpful. I’ll go over everything tomorrow but I bet something’s not routed correctly.

I’m getting close. Hoping to actually drive the car one day...

I’ll update tomorrow.


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[Dr.D]

OK. I figured it out. I checked all of the fuel lines to make sure I had them hooked up right. They were. I even pulled out the fuel pump just to make sure all was good with those connections, etc. All was fine.

Then I did the start thing without the RPM relay while reaching over from the passenger side (the seats are out) and it started. Before it died, I quickly plugged in the relay and it stumbled for a second or two but kept going. It seemed like it was running VERY rich though. I used the allen wrench, while it was running, to lean the mixture and as I did it, the car ran smoother and smoother. I literally turned it counter-clockwise about 2 1/2 full turns (which I know is a lot). Car ran great, idled, smooth, etc. I let it run for a minute or so and then turned it off. Let it sit and tried again with the relay in and it started right up!!!! Runs very smooth and starts every time!!!

The idle is a bit high. It's running about 1100 RPM. I adjusted the timing and readusted the mixture slightly. Still high idle. I'm not going to worry about that today. I'm having a drink or two to celebrate!!!!

I am looking forward to getting the car ready to actually drive over the next week or two. I've got to bleed the coolant system, get the idle thing sorted out, and make sure my brake rebuild is all good before I try to hit the road.

Thanks to everybody for all the help. I'll keep you posted on progress!

Cheers!

[Ron]

:thumbup: Good job!

[David T]

Rather unusual for the mixture unit to be so far off. Was it ever in a running car? Was it sent out to John H for rehabbing? Did the PO mess with it to possibly compensate for massive air leaks?

[Jonathan]

Is there a standard amount of turn the mixture screw can go? I ask because the OP mentioned 2 and 1/2 turns and when I was doing mine, I think it went from a too rich stall to a too lean stall in only a half turn total. Like one extreme was 9 o'clock and the other extreme was 3 o'clock. I have not seen what exactly things look like inside to know what is turning so can't visualize what the limits might be (if any).

[Dr.D]

If you watch the k-jet video on YouTube or look at the diagram for the mixture unit, the little screw goes between the flapper and the plunger of the FD. I agree the normal adjustment range is about 1/2 turn total.
I bought the car as a “barely running” project. I never ran it since the fuel system needed a complete redo. I’m sure the PO “adjusted” the mixture to compensate for vacuum leaks and a gummed up fuel system. I’m just glad I figured it out.


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[Ron]

$.02
Adjusting the FD may have 'compensated' for a problem with the WUR/CPR or ISM....

[Bitsyncmaster]

On my car using a dwell meter, I get less than a 1/4 turn to get the lambda maxed out (no more lambda adjustment) rich to lean.