Engine fires, runs, then quits immediately

[Bitsyncmaster]

I'm quite sure the CO plug is there, but I will double check when I get home. If it's vacuum, I'm leaning towards the pipe of agony got pulled out partly when hooking up the idle motor.

I'll be back on tonight, hopefully, after I get a chance to check some of these ideas, with an update.

The mixture plug is not a very large leak. You can shine a light down around the pipe in the dark and press the air plate down and look for light inside the FD.

[AugustneverEnds]

The mixture plug is not a very large leak. You can shine a light down around the pipe in the dark and press the air plate down and look for light inside the FD.

My car must be very partial to its mixture plug, it ran like crap, backfired a little, and refused to start or restart without starting fluid before I thought to check it and cover it.

[Bitsyncmaster]

My car must be very partial to its mixture plug, it ran like crap, backfired a little, and refused to start or restart without starting fluid before I thought to check it and cover it.

Mine has very little affect even when measuring dwell. I do cover it to finalize the dwell adjustment.

[Ron]

A couple weeks ago I blew one of the upper water pump hoses (the one that connects the pump to the passenger side head). It was about 15 years old, looked fine, pliable, but on inspection during removal, it had a crack on the inside. So, I decided it was time to go into the valley once again for a freshen-up and to replace all the coolant hoses on the engine. Everything went well and I did the following:

• Removed ignition distributor to replace the o-ring on the shaft (oily residue around the distributor) and new impulse coil. First time taking the distributor apart but it went fine and I was sure to mark the timing nut and the rotor position - such that when I dropped it in, the rotor turned and hit my mark. I think it's fine? Also replaced cap (DMCH) and rotor (Bosch from Rock Auto) as well as new plug wires (DMCH)
• Checked plugs which I installed this summer to make sure they look good - all look perfect
• Machined the Y-pipe surface
• Removed all three sensors from the Y-pipe for cleaning, the 3-way switch broke so I put a new one in (DMCH)
• Updated the heater pipe to the DPI version (no more metal snake)
• Replaced all vacuum lines
• Routed engine harness under the air meter
• Replaced all O-rings and gaskets to get into the valley including pipe of agony o-ring and FD o-ring
• New belts
• Thin coating of anti-seize on every screw, new washers for everything
• Replaced PPR o-rings with D-go kit

Got it all back together no issues last night and tried to start it - it will turn over, fire, start, but then quit right away. Prior to this work I had no starting or running issues so it's something I have done this weekend.... See the video below.

My questions/thoughts:

1. I checked fuel pressure with my K-Jet gauge and my primary and control pressures are correct, rest pressure is fine but I do hear the accumulator clanking sometimes after turning off the fuel pump. Don't really remember that before. I have not tried to check pressure while the car is starting and trying to run.
2. I have not checked timing yet - I haven't done this in YEARS so as a refresher, is it OK to check timing with the fuel pump off and having a friend turn the key so the engine and ignition is running for a few seconds while I use the light?
3. How far into the air meter should be the pipe of agony be sticking in? I can see it through the meter plate if I release the fuel pressure and push down on the plate - I will check this again but I know the pipe is in there, just might not be far enough somehow
4. Does it matter which wire goes to which terminal on the idle microswitch? It's possible I got the wires reversed but I don't think so. I have the ground on the bottom terminal and the power on the top terminal right now.
5. When I removed the brass pipe for the CSV from the intake manifold, for some reason there was a copper washer down in there (in the pit where the long screw threads into). It's not in the parts manual so I removed it thinking it can't serve any purpose like that. Was I mistaken?
6. Thinking back about everything, it's POSSIBLE I forgot to torque the spark plugs down. I know they are threaded in by hand using an extension but now I'm trying to remember if I hit them with the torque wrench.... I think this would create a bad enough compression problem where the engine can't run, right? I'm going to check this first when I get home after work.

Appreciate any other ideas based on the evidence provided!


https://youtu.be/ub1kBN1S7cY

1. Maybe see if it will stay running with short spurts of staring fluid.
2. In the vid, the tach appears to show ignition while it is dying (see #1 above ;-).
3. If you can see the entire opening, it's probably not the problem.
(It passes through an o-ring and it's keeper. )
4. It doesn't matter which wire goes to which terminal on the ISM micro switch.
5. The long bolt goes through a copper washer, the bypass pipe, and then an o-ring.
(Check this out).
6. All else ok, if the plugs are hand tight, it would run. (Not good for the threads, of course.)

[82DMC12]

Ron, the CSV washer I was talking about was a copper washer that was laying flat on the bottom of the intake under the brass pipe and the long screw went through it. Made no sense and didn't see it in the parts book.



Well I haven't learned too much yet but I did eliminate a few things.

1. I finagled the Pipe of Agony and the associated elbow hoses and got it to go another centimeter into the air meter and also confirmed the o-ring is still in place. I think we can conclude there are no vacuum leaks between the CVS to the lower air meter.

2. Confirmed the large vacuum line is going to the passenger side rear intake (hose clamped tight) and the manifold vacuum to the three way switch on the Y-pipe is also plugged in.

3. Rechecked all vacuum routing - OK

4. Removed and reinserted all wires to the ballast resistor and the ignition coil - Seems OK

5. Spark plugs were indeed torqued to 14 ft lbs - didn't forget! Checked plug wires - OK

Not much luck. It still starts after three or cranks but then dies right away just like in the video. However now I can give it a bit of gas pedal once it starts and I can get it to rev with each press of the pedal, but it sounds weak, and of course dies as soon as I let off the gas.

I'm trying to eliminate vacuum leaks as a cause so I'm thinking about the places it could leak that I touched.

• Pipe of agony - checked and should be OK now
• W-pipe paper gaskets - checked
• W-pipe o-rings - now I'm missing the "Back Up Rings" 102282 and I think I've always been without them. I have the o-rings on the W-pipe and I tried to double-up the rings like suggested on DeLorean.com but I couldn't get it to go together that way. I ordered the back up rings from DPI and will put them in as soon as I get them.
• Air meter halves gasket - replaced this and used red spray-tack gasket sealant, tightened all cap screws
• Didn't mess with the meter plate or the CO screw but I did clean everything in there with carb cleaner. I did look at the plate with a light behind it and it looked perfectly even all around.
• Throttle spacer - cleaned with silicone spray, it's not damaged
• Cleaned throttle with carb cleaner, worked the decel springs and made sure they were seated properly before installing the throttle.
• Confirmed the throttle is indeed closed
• Two manifold ports on the rear upper parts of the intake manifold - hoses are on
• Six intake o-rings - replaced, didn't use any grease, put them in dry. Carefully added the intake manifold over it and tightened the four manifold bolts in criss cross. Looking at the head-to-manifold mating area it appears even and flush. I did lightly clean the manifold mate surface with a pneumatic wire wheel.

Not quite sure where to go next! I'm afraid I may have to tear back down to the valley again and check everything from the bottom up....

[DMC-Ron]

4. Removed and reinserted all wires to the ballast resistor and the ignition coil - Seems OK

I know your checked the ballast resistor, but you might do a very simple test to insure the white with yellow (W/Y) wire headed to the coil is getting +12 with the ignition switch in the run position. The car can start from the cranking power provided to the ballast resistor then drop out when the switch returns to the run position.

Ron

[MrChocky]

A the risk of saying something completely obvious, and I didn't see this mentioned, have you checked you TTS plug? On mine, one
of the pins backed out, and I had cold start symptoms that sound a lot like what you're having.

[82DMC12]

I know your checked the ballast resistor, but you might do a very simple test to insure the white with yellow (W/Y) wire headed to the coil is getting +12 with the ignition switch in the run position. The car can start from the cranking power provided to the ballast resistor then drop out when the switch returns to the run position.

Ron

Hi Ron,

In RUN, I am getting +12V to white/yellow at the coil but only if I remove the wire from the dual spade (which is shared with a noise suppressor yellow wire) and test it by itself. But then, if I plug the white/yellow wire back into the coil (key still in RUN), and I measure the coil terminal that I just plugged it into, I am getting 5.8V. Does that sound right?

I reconfirmed all the wires on the ballast resistor are connected tightly and also removed and reinserted the resistor grid relay.

[82DMC12]

A the risk of saying something completely obvious, and I didn't see this mentioned, have you checked you TTS plug? On mine, one
of the pins backed out, and I had cold start symptoms that sound a lot like what you're having.

No bad ideas here. I did remove the plug and inspected it, the pins are both in the correct position and it feels secure when I reinstall the plug.

[82DMC12]

So I was just reading this thread -

http://dmctalk.org/showthread.php?12...uestions/page2

In it, Dave M says white/yellow should go to + terminal on Accel coils. Mine has been wired up opposite that for probably 15 years. Is that a thing? I've never had ignition problems until now so I'm not sure I should swap it....

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