Engine starts, then dies. Help, I'm stranded!

[rockable]

My '86 Truck w/ 305 and all smog equipment has been running great and was doing so until a minute ago.  All of a sudden, while going through a drive through, the engine started to idle rough and then die.  It will crank back up but as soon as I release the ignition key, it dies. 

It's like a ballast resistor is burnt out or something.  There is no ballast resistor on this truck, is there?

Thanks for your help.

[rwhit57]

Start with the simple stuff, make sure it's getting fuel. Might be as simple as a clogged fuel filter. If it's getting fuel then, check the cap and rotor, next guess would be an ignition module, especially if it's hot outside heat tends to knock those out, but normally it will not try to start at all with a bad module. Just start with the small stuff and eliminate them one by one.

[1979C20]

Sounds like its choking on fumes. Try putting gas in your tank and into your intake.

[rockable]

It's full of gas.

What do you mean by ignition module?  The coil in the cap?

[rwhit57]

The ignition module is in the distributor has wires that plug into each end. I'll see if I can find a pic. Are you still down?

[rockable]

Yes.  It WAS hot today.  The truck has been running fine and pulling hard at WOT, so I don't really think it's a fuel issue.  25 year old electronics are more likely the culprit.  Since I didn't have anyone with me, I couldn't test for spark but it starts instantly and then dies.  It's like when it switches over from "start" to "run", it dies. 

So this module is in the distributor.  I know I replaced the plugs, cap and rotor less that 6k miles ago.  Someone suggested to me that the green wire from the solenoid to the distributor is pretty commonly known to go "open" on these engines.  Anyone know about that?

[rwhit57]

I have never had that issue with one of these trucks, but an easy way to check it would be to get a length of wire and run it from the pos post on the battery to the dist, be sure and unplug the orig one. The truck should start up. If it doesn't I'm guessing fuel supply or ign module. Have you tried squirting gas to it to see if yu can keep it running?

[1979C20]

Best way to rule out the distributor is either swap it or test it. If youre going to take it out, i recommend pulling the cap off, and take a picture of the rotor and which way it is pointing. When you put it back in, just match everything up to your picture and your timing should stay the same. But, the correct and safest way is to bring number 1 piston to tdc conpression and set your distributor in with the rotor pointing at the number 1 cylinder. This is the easiest way to reinstall your distributor(in my opinion) http://forum.73-87chevytrucks.com/smforum/index.php?topic=20821.0. If you pull your distributor you should be able to take it down to a parts store and have each component tested. Good luck!

[78 Chevyrado]

Check your battery cable connections at the battery.  I've had several cars do what you said your is or just totally die in the middle of driving because of corrosion.

[Irish_Alley]

did you ever check the fuel to see if its the problem. your tank can be full but a clogged filter will do this also. it will let enough fuel in to fill the bowls but thats it, then once you start it the filter wont allow enough fuel in and kill the engine. once it dies how soon before it can restart i.e. multiple turns or till it cools down

[rockable]

After loading up my jack, jackstands and half the tools I own, I drove back to the scene of the crime this morning to check it all out.  I had nothing to work with yesterday and it was hot as blazes.  I got in the truck and it started right up and I drove it home without a single hiccup.  Now, I know whatever is wrong is going to happen again.  So, I've got to figure it out.  At least I can do it in my shop and not in some hot parking lot.

The truck had been running fine down the highway and it was idling when it shut off.  I've had no indications of a fuel supply problem.  In fact, I was just thinking about how great it was running yesterday morning.

I'm going to remove the distributor cap and inspect everything under it for cracks.  Also, I'm going to check the fuel filter.  I guess the one that goes into the inlet of the carb is the only one.  Correct?  If I'd had to guess now, I'd say vapor lock is a likely culprit but there is no restriction on the inlet side of the fuel pump that I can see.  I hate troubleshooting intermittent problems.  You never know when you've got it fixed............for sure.

Thanks, Guys.

[Irish_Alley]

since it started back up and gave you no fuss then i would say more electrical problem. to me its had to say since it would initially fire up then once you stopped the starter it would cut off

[rwhit57]

I think the fuel filter would be a good place to start, some sediment could have clogged it up, then backed off after it set.

[Lt.Del]

next time it happens, try your best to check for spark...it will either point to or eliminate ignition module and or pick up coil in distributor.  Running at WOT for a while put a lot of heat under da hood and i had a bad pick up coil once and it wouldn't work when truck was hot.  cool it down, worked fine.  I replaced the whole distributor.  If you are getting spark, i'd go with the last post of rwhit57.

[Grim 82]

This has Electronic Spark Control written all over it.