Hello everyone I have a 1991 z28 305. I changed the plugs wires coil pack and
Distribitor. I timed it it will fire right up and runs nice. When hot Itturn it off and can fire
It right back up. If I wait 5 minsthe car will not start till it cools down then will start
RRight up again. Someone told saidit could be the module on the distributor
So iI replace that even thought it was new. Anyone had this problem before ? Thanks
For any help

 

Heat sink in your starter?

 

I dont think it is that. the car truns over just wont fire. I check the spark on the #1 plug when it was doing this and the spark is weak. it is there just weak. thanks anyother suggestion would be appreated.

 

Ignition coil - weak coils will usually break down with heat - I've had cars do exactly what you're experiencing - takes a little while to heat soak then the spark is so weak it can't light off the lean mixture. Replaced the coil and everything was good again. Usually if it's the ignition module you start to get occasional stalling with either an immediate restart or having to wait until it's cool to re-start.

 

Thanks. When i did tune up i replced coil pack. So that is new. Any other thoughts would help. Thanks again

 

If you're sure it's a weak spark and not loading with fuel due to leaking injector(s) then there are only a couple of parts that create the spark - primarily the distributor(module), the coil itself, and then the computer. Also the pink wire (if I remember it right) to the coil should have a full 12v to it when cranking and with the key on - test the voltage there and if it's low then you may have a bad connection somewhere in the supply side.

When it doesn't start - does the car pop or sound like a few cylinders are firing or it's trying to start or does it just spin with no sign of firing or anything? Have you tested the fuel pressure and see if it holds pressure once the vehicle is shut off?

 

fires up sounds good. I will check what you said in next few days. thanks again

 

What about when it does NOT start??? What does it do? cranks fast but no popping or stumbling, etc.?

 

no popping just sounds like it wants to start but does not

 

Have you tried holding the pedal to the floor and cranking it over and seeing if it clears itself and starts? If you have injector(s) leaking down it can temporarily flood a few cylinders with fuel and cause it to be hard to start but holding the throttle to the floor tells the computer not to inject fuel and clears the flooded cylinders. Also if the coolant temp sensor for the computer is not working it can trick the computer into thinking it's still cold and it would want to enrich the mixture making it hard to start - but usually that's accompanied by poor gas mileage and it would be harder to start within a few seconds of shutting it off and wouldn't have to heat soak...

Another thing to try is to add a little fuel into the intake if you think it's not getting fuel (or starting fluid) and seeing if it fires off with additional fuel.

 

bwiencek ,,,thanks for the advise. I am off the weekend and will try these then. I will get back on this weekend and let you know. thanks again for the help. i am a beginner at this.

 

Just a note.

Even though you changed the coil, don't rule that out. In fact, put a different one in first.

I have gone through 2 brand new coils over the last year. One was a MSD coil and one was a stock replacement. Its very easy to get a bad "new" unit.

Clearly you're having spark troubles, so don't be left scratching your head just because you bought a new unit.

 

And the new distributor cam with new ignition control module?

 

For the symptom at hand, I would say the cap and ICM would be less likely to be the culprits...

However, if the ICM does not have thermal grease evenly applied, it may be heating up and causing problems. But if the ICM was causing problems, I would expect to see miss-firing, especially when load is applied.

 

I replace the distributor and then replace the module even though it was new and I know I have the grease applied nice and even then it's back downI guess I can try another ignition coil I just felt if he could I just spent 40 bucks on the module on that wasn't it but I can try that I was going to try the holding the pedal to the floor cuz I do smell a lot of gas not a lot but I can smell gas when its trying to start

 

I just had the car running late warm up turned it off it would not start. doing the same thing wouldn't turn over held my foot to the floor and it fired up and then it would stall. I could start it again with the pedal to floor and it would stall. But turned over. So what do you think I should do next. Do I need to replace the injectors and is that hard or expansive n

 

Sounds like it's flooding for some reason then - the only logical choice is a few injectors are leaking when the engine is off and probably even while it's running - I'd pull and clean the injectors or send them out for cleaning - if you can find a local injector service place that has a flow testing and cleaning station they can usually turn them around in a day or two - usually a lot cheaper than replacing them with new ones.

 

Thanks again I will try.