runs for 40 minutes, then dies and will not re-start

[Farrar]

After running about about 40 minutes, the engine will not hold an idle and dies. I cannot re-start the engine until it is cold.

Any help would be greatly appreciated.

[Bitsyncmaster]

After running about about 40 minutes, the engine will not hold an idle and dies. I cannot re-start the engine until it is cold.

Any help would be greatly appreciated.

Sounds like a spark problem since it runs for so long. Could be the coil, pickup or ECU. Can you verify there is no spark after that 40 min?

[Farrar]

Sounds like a spark problem since it runs for so long. Could be the coil, pickup or ECU. Can you verify there is no spark after that 40 min?

You may be on to something there, Dave... I was using my tachometer in the engine compartment to monitor engine speed, and noticed the reading fluctuating wildly just before the engine died. The tach receives its signal from the coil's positive terminal. I will go and see if I have spark.

[DeLorean03]

Find the plug on the left side of the engine that connects to the electrical distributor. It's similar to the CSV and WUR/CPR plug - instead of blue or brown, it'll be a yellow color. Then do the following:

Straight from John's site:

This may be the problem when the car won't start until it cools down from being hot or if your car just dies and won't start for no apparent reason. Let it cool down for about 45 minuets and starts up. Should measure about 550 ohms room temp on the wire coming out of the ign distributor. When is gets hot and the car dies, there will be no ohms reading.

He is referring to the pulse coil in the electrical distributor going bad.

From this page:

http://specialtauto.com/delorean-parts/electrical.html

[Farrar]

Thanks. I confirmed plenty of spark while cranking but no start. It had been more than 45 minutes since the engine died.

I found instructions for testing a pickup coil here (http://www.autozone.com/autozone/repairinfo/common/repairInfoMain.jsp?targetPage=productsHowToInspect&pageId=%090996b43f80a01359&subtitle=test). If I get the chance, I'll try this tomorrow.

[DMC5180]

Thanks. I confirmed plenty of spark while cranking but no start. It had been more than 45 minutes since the engine died.

I found instructions for testing a pickup coil here (http://www.autozone.com/autozone/repairinfo/common/repairInfoMain.jsp?targetPage=productsHowToInspect&pageId=%090996b43f80a01359&subtitle=test). If I get the chance, I'll try this tomorrow.


Your running A Carb aren't you. Plenty of Spark but NO start. What about Fuel supply? What happens if you shoot a little Starting fluid in the Carb?

[Rad Dad]

Thanks. I confirmed plenty of spark while cranking but no start. It had been more than 45 minutes since the engine died.

I found instructions for testing a pickup coil here (http://www.autozone.com/autozone/repairinfo/common/repairInfoMain.jsp?targetPage=productsHowToInspect&pageId=%090996b43f80a01359&subtitle=test). If I get the chance, I'll try this tomorrow.

If you know me you know I am not mechanically inclined-- BUT after32 years of ownership, I have learned a few things and even though I am now 80, my memory is pretty goo. SO, you have perfectly described the dreaded "impulse coil" problem .. . . At least as I experienced it.

Dick Ryan, the Rad Dad

[Farrar]

Yes, I'm running a carb. The engine is getting fuel. In fact, unless I turn the key off when the engine dies, the needle valve can't hold the pressure back for very long and the carburetor floods out.

It sounds like the pickup coil might be the culprit. RockAuto has one for $14 shipped. I might as well jump on it.

[David T]

Yes, I'm running a carb. The engine is getting fuel. In fact, unless I turn the key off when the engine dies, the needle valve can't hold the pressure back for very long and the carburetor floods out.

It sounds like the pickup coil might be the culprit. RockAuto has one for $14 shipped. I might as well jump on it.

If it has spark it is NOT the impulse coil. Sounds like it is running too rich and choking on all of that fuel. Or it could be vapor lock. If the fuel going to the carb gets too hot it can turn to vapor in the fuel line or even the carb.

[Silverbullet]

Yes, I'm running a carb. The engine is getting fuel. In fact, unless I turn the key off when the engine dies, the needle valve can't hold the pressure back for very long and the carburetor floods out.

It sounds like the pickup coil might be the culprit. RockAuto has one for $14 shipped. I might as well jump on it.

Ah.... If the carb needle can't hold the fuel back... there is an issue... Did you put a in-line Fuel Pressure Regulator? If not, you should... Carbs don't need that high pressure...

Craig

[Farrar]

Ah.... If the carb needle can't hold the fuel back... there is an issue... Did you put a in-line Fuel Pressure Regulator? If not, you should... Carbs don't need that high pressure...

Craig

The pump I'm using is rated for 5-9 PSI. However, I am considering adding a regulator set at 6 PSI. Or I could just put a resistor in the circuit to slow down the pump, ha ha...

[David T]

The pump I'm using is rated for 5-9 PSI. However, I am considering adding a regulator set at 6 PSI. Or I could just put a resistor in the circuit to slow down the pump, ha ha...

What he is saying is the needle valve for the float can't hold back much pressure over 5 psi. When you shut the motor of the valve leaks, overfilling the bowl and leaking into the motor. With all of that raw fuel sitting in the intake manifold it can't start. The fix is to get a lower pressure pump and/or a pressure regulator so the float valve doesn't see so much pressure. Typically you only need 3-5 psi on a carb. It is really only enough for transfer, you do not need a lot of pressure, only flow.

[Farrar]

Tonight, I tried to insall the new pickup coil. With the help of the Workshop Manual, this is as far as I got.

http://25.media.tumblr.com/82f124035b5bec96ffb6d7ea1e8ea4ee/tumblr_mu9x7hztUu1stq9e4o4_1280.jpg

After that, I couldn't get anything to come apart anymore. The three screws on the inside were a pain -- one came out OK, the second fell down inside the housing where the torque converter is, and the third refused to budge so its head is all mottled now.

I also tried removing the vacuum advance mechanism from the outside (two screws) but it wouldn't un-latch from whatever it attaches to inside.

[DMCMW Dave]

I'm not sure I'd try to do this with the distributor still on the engine. You have very easy access to get it out, take it off the engine (put the rotor back on and set it to the TDC mark so you can put it back together aligned).

You MUST take the vacuum chamber off, at least the screws that hold it in place, and you can't really get a screwdriver on them. They will be tight. The screws that hold the vacuum chamber on are so long that they block you from removing the plate.

The biggest risk, and it seems to be something you've already run into, is dropping small things into The Land Of Lost Parts. The C-clips and tiny roll pin are pretty easy to drop, and not something you'll find at Pep Boys.

[Farrar]

The distributor was mounted for the ease of taking pictures. The distributor itself has been removed from the car.

The C-clips were easy enough. That's what snap-ring pliers are for. The roll pin was not a problem, because the magnetic ring stopped it from falling.

I'm still stuck.


https://www.youtube.com/watch?v=SaNzEXnbkKQ

[David T]

The distributor was mounted for the ease of taking pictures. The distributor itself has been removed from the car.

The C-clips were easy enough. That's what snap-ring pliers are for. The roll pin was not a problem, because the magnetic ring stopped it from falling.

I'm still stuck.


https://www.youtube.com/watch?v=SaNzEXnbkKQ

You must take the whole thing apart. To do that you can't do it on the motor. There is no good, exploded view in the Parts Manual. Get your Workshop Manual out and go to M:01:01-:02-:03. You must check and if necessary set the Trigger/Stator gap on all of the points to 0.25 mm using a brass feeler gauge after putting it all back together and when you reinstall the distributor you should check the timing and the mechanical and vacuum advance. Are you a betting man? I bet this does NOT fix the problem. In fact, it may add to them. BTW, keep track of all of those little parts and spacers. You must reassemble it EXACTLY as it was assembled. Lightly lubricate all of the moving parts inside.

[Farrar]

November 2013: I let someone else swap out the pickup coil in my distributor.

December 2013: I re-installed the distributor. The engine would not start.

Today: I installed a new ignition module. The engine would not start.

[David T]

November 2013: I let someone else swap out the pickup coil in my distributor.

December 2013: I re-installed the distributor. The engine would not start.

Today: I installed a new ignition module. The engine would not start.

Most likely problem now is you did not reinstall the distributor correctly. Rotate the motor till the piston in cylinder #1 is at TDC on the compression stroke. Now install the distributor with the rotor pointing at cylinder #1. Recheck your firing order and try again to start it.

[DMC5180]

Most likely problem now is you did not reinstall the distributor correctly. Rotate the motor till the piston in cylinder #1 is at TDC on the compression stroke. Now install the distributor with the rotor pointing at cylinder #1. Recheck your firing order and try again to start it.

Do not see any confirmation there is spark either. Just statements of replaced this or that.

[Farrar]

Do not see any confirmation there is spark

That's strange, because:


I confirmed plenty of spark while cranking

[DMCMW Dave]

That's strange, because:

Then I agree that the timing is set wrong.

[Farrar]

Then I agree that the timing is set wrong.

How badly does the timing have to be off in order to prevent the engine from starting?

[DMCMW Dave]

How badly does the timing have to be off in order to prevent the engine from starting?

A couple teeth on the distributor. Common is 180 degrees off and it definitely won't start there.

[Farrar]

A couple teeth on the distributor. Common is 180 degrees off and it definitely won't start there.

I may be as far off as a centimeter. I guess I'll have to do the old "find TDC on cyl #1" trick.

[opethmike]

I may be as far off as a centimeter. I guess I'll have to do the old "find TDC on cyl #1" trick.

I can help you with this. Let me know if you need me to dig up the notes I posted to your FB a few weeks back, or I can give you my number if a phone call is preferred.

[Farrar]

I can help you with this. Let me know if you need me to dig up the notes I posted to your FB a few weeks back, or I can give you my number if a phone call is preferred.

Actually, I printed those out. Thanks! I'm going to try to find the time this weekend. If I'm lucky, I won't have to remove the muffler...

[Bitsyncmaster]

But even 180 deg off, the tach should show movement when cranking. Did not see any tach movement on your video you posted elsewhere.

[Farrar]

But even 180 deg off, the tach should show movement when cranking. Did not see any tach movement on your video you posted elsewhere.

Tach registered earlier. I'll check connections.

[Rich]

I may be as far off as a centimeter. I guess I'll have to do the old "find TDC on cyl #1" trick.

You can probe #1 cylinder or you can look at the timing mark to find #1TDC.

Remember that #1TDC occurs twice per combustion cycle and once per revolution, one for #1 ignition, the other for the end of the #1 exhaust stroke - 180deg different at the distributor and 360deg different (i.e., the same) at the crankshaft.

[opethmike]

You can probe #1 cylinder or you can look at the timing mark to find #1TDC.

Remember that #1TDC occurs twice per combustion cycle and once per revolution, one for #1 ignition, the other for the end of the #1 exhaust stroke - 180deg different at the distributor and 360deg different (i.e., the same) at the crankshaft.

Yes; for setting the distributor, the cylinder needs to be on the compression stroke.

[Farrar]

So in theory, a procedure for this would be:

- Line up the timing notch on the crankshaft pulley with the 0° timing mark on the gauge mounted to the engine.
- Line up some markings on the distributor.
- Try to start the engine. If it starts, I got it right. If it doesn't, I'm 180° off.

Where are the markings on the distributor? I can't see any. Sorry for my ignorance, but I've never done distributor stuff before.

[Spittybug]

So in theory, a procedure for this would be:

- Line up the timing notch on the crankshaft pulley with the 0° timing mark on the gauge mounted to the engine.
- Line up some markings on the distributor.
- Try to start the engine. If it starts, I got it right. If it doesn't, I'm 180° off.

Where are the markings on the distributor? I can't see any. Sorry for my ignorance, but I've never done distributor stuff before.

The individual spark plug wires are your "markings". When the rotor is pointed to #1 wire, you've got it! (With the timing mark on the crank at zero). If the rotor is pointing away from it.....you are on TDC of the exhaust stroke. When you rotate the distributor to advance or retard the timing, what you are physically doing is changing where the spark plug wire terminals are relative to the rotor. IIRC, the rotor turns clockwise, so rotating the body of the distributor counter clockwise means the spark gets to the plugs sooner, thus you are advancing the timing. See what I mean?

[DMCMW Dave]

The distributor has a timing mark on the body casting that corresponds to the correct timing at TDC on cylinder 1. Assuming you are on the compression stroke.

25068

[Farrar]

... See what I mean?

Yes! That sounds a lot less complex than I thought it was! Thanks!


The distributor has a timing mark on the body casting that corresponds to the correct timing at TDC on cylinder 1. Assuming you are on the compression stroke.

Thanks, Dave! That picture really helps. Evidently my distributor is dirtier than I thought it was. :[

I take it that the crankshaft spins twice for every one spin of the ignition distributor?

[DMCMW Dave]

Thanks, Dave! That picture really helps. Evidently my distributor is dirtier than I thought it was. :[

I take it that the crankshaft spins twice for every one spin of the ignition distributor?

Yes. You need to have #1 on compression stroke. The easiest way to find that is to pull out #1 plug and put your finger in the hole, then turn the engine over until you feel air coming out. Then align the pulley mark.

[Spittybug]

Farrar, I think you need to host a magnificent New Orleans crawfish boil and entice a few of us Houstonians to come over for a tech day. We'll get you running or we'll just convert you to EFI! Hell, maybe I'll even brew a special beer for the occasion and bring it. We'll call it "Kra-Z Cajun Ale".

[Farrar]

Well, today I managed to get the exhaust clamps off and not budge the muffler a friggin' hair's width in any direction. There's no way I can get a socket on the crankshaft nut with that giant PERFORMANCE MUFFLER in place. I thought maybe I could manage if I just removed the heat shield and tried to get the socket on from underneath, but although the clamps and their hardware are stainless, the hardware holding the heat shield is not, and I was only able to remove one of the bolt/washer/nyloc assemblies before rounding out the second and giving up.

It looks like I will spend the next few months saving up for an exhaust pipe cutter. Those suckers ain't cheap.

Amazing that this all started with me trying to re-charge the air conditioning last year...

[Farrar]

Change of plan: I decided to see if I could disconnect the flanges where the headers meet the cat pipes. They've been soaking in penetrating oil since last night. If I can get those to separate, I can drop the muffler assembly that way.

[DMCMW Dave]

Change of plan: I decided to see if I could disconnect the flanges where the headers meet the cat pipes. They've been soaking in penetrating oil since last night. If I can get those to separate, I can drop the muffler assembly that way.

Those should come right apart. Replace the 4 big bolts with stainless. This also preserves the alignment so it goes back together easily.

BTW - you can bump the engine around to TDC with the starter.

[Bitsyncmaster]

BTW - you can bump the engine around to TDC with the starter.

I've turned a few with the fan belt. You would need to remove the plugs and get some wrench onto one of the upper pulleys.

[Spittybug]

Too bad you aren't a manual gear box. A simple rolling when in gear is the easiest way.

[Farrar]

Those should come right apart. Replace the 4 big bolts with stainless. This also preserves the alignment so it goes back together easily.

BTW - you can bump the engine around to TDC with the starter.

I tried bumping with the starter, but it was just too much of a hit-and-miss affair.

You're right, though - as badly rusted as that hardware was, it came right apart after an all-night soak in acetone/ATF.


I've turned a few with the fan belt. You would need to remove the plugs and get some wrench onto one of the upper pulleys.

I tried that, too.

The hardware came off. Three of the four nuts took a 17mm wrench. One took a 15mm. See if you can spot which:

25163

Give up? Bottom right.

Anyway, this is where I am now:

25164

I lined up the distributor, confirmed spark (again), sprayed some starting fluid down the carb and cranked it. The carb went "POP" and smoke came out. I think I may be 180° off or used the wrong notch on the crankshaft pulley.