Hi everyone. I have a '92 Camaro RS with a TBI 305. Occasionally, when I stop the car (turn it off) and try to restart it, it will crank but not start.
It is a no spark problem, as I have checked it with a spark tester, and there is no spark.
From there I would check the ignition coil, which is fine.
The annoying thing is that usually during these checks (which show everything to be fine), the car will start up again like nothing was ever wrong! From that point, it will start up fine for a few days, then when I least expect it, I will stop somewhere and it won't start again.
I will start checking things again, and it's a repeat of the same situation: It will start after a little bit of messing.
The car has never died on me while it is running; it only loses spark when it is turned off. And the problem is intermittant and seems to happen completely at random.
I have already replaced:
Ignition coil (externally mounted)
Distributor cap and rotor
ignition module

The car has an MSD 6AL controller on it.
Can y'all reccomend any other tests or checks that I haven't tried?
I have a Haynes manual, but it is incredibly vague and doesn't say much of anything about cars with an externally mounted coil like mine.
Any help is appreciated.

 

The spark is generated by the distributor and the ESC module by grounding the coil. So you need to focus on these components and their wiring.

One of the easiest checks is to have somebody crank while you're messing with the distributor and coil wiring. It could be just a broken wire.

You say that components have been replaced. That doesn't necessarily mean that they are good.

Check for power to the coil and distributor (pink wires). While checking, tug on the wires, you should NOT lose power.

Hope this helps.
Lou

 

It sounds like there is something related to heat or temperature. I had a car that when I would stop the engine and then start it before cooling off it would not fire. It turned out to be a cam sensor (our cars do not have these) Of course it may be something similar that is being effected by the heat of the engine.

You may have a bad coil, or the ESC module in the distributor that when it gets warm it breaks contact. You might also have a corrosion on one of the contacts that when it gets hot no longer makes good contact.

BBL pretty much covered it, but thats my thoughts....

 

Thanks for the suggestions guys! Just as an update, it did it again last night. I was gonna run to the store to get a soda, and it wouldn't start.
I went to the store in my dad's truck, came back and tried the car again (keep in mind that I haven't touched anything under the hood or moved anything except the ignition switch), and it started right up!

 

John is right, it could be something related to heat.
If you let the car cool down without touching anything, does it always start later? That would be one indication.

We've had another thread like that here just in the past week or so. Heat related no-spark. Not sure where they got with the troubleshooting, haven't heard back from the kid. Feel free to check it out for ideas and diagnostic procedures.

Lou