ok hi guys new here, i recently had this start happening i can get in my car and start it no prob drive some where shut it off come back out and it wont start , it cranks over no securiy light or anything ,fuel pump comes on and has been replaced, then if i wait a bit it will start right up and be fine it does this every once in awhile not all the time any ideas where to start looking

 

Not sure how to take your security light comment. Not sure if it is even related. However it sounds like the ICM might be a problem. It is affected by heat and when it goes bad it can cause a number of symptoms like no start or will just quit.

This is just one place to start. You can check fuel pressure but it sounds like a spark issue.

 

If the car runs fine once it does start here are a couple of things you can try to diagnose if it is ignition related.

1. An inline spark plug test light connected to the coil will allow you to see if the coil is firing while cranking. If the coil is firing consistently and strongly then it is likely that the coil, ICM, ECM and associated wiring are ok. If the coil is not firing then you will need to isolate each component including the distributor to see what is wrong. It would be best to get a factory service manual if you want to do this although there is a lot of info about doing this on the web.


2. If the coil is firing then connect the inline spark plug test light to one (or several) of the spark plugs, start cranking and see if the energy is getting through the distributor to the spark plugs. If the spark plug light is firing consistently and strongly then you will need to expand your search for the problem to the fuel system, etc. It would be best to get a factory service manual at this point. If the light is not firing while cranking then the problem almost certainly lies inside the distributor.

 

I just read your question more thoroughly and realized my answer would not
have helped.
My problem is somewhat related but when it happens, it won't even crank for about 4 minutes.
Sorry for the post.

DMheart: 88 vette (heartbeat logo)

 

it seemed to me like it might be in the security system its about 4 minutes atfer the first offical no start that it fires back up but there is no security light on or flashing when i crank it im going to replace the icm tom. c what happens, its one of the dam probs that dont happen all the time but it happened way more that 1 time done it cold and hot

 

That's exactly how it happens to me and I had a reminder of it today after I went into a local store and came back out.
Seems tempermental. I give it about 4 minutes (or enough time to smoke a cig) and it'll crank back up as though nothing was ever wrong.
I read an article recently where the ignition switch is the culprit ...
that the tumblers have become worn after so many years of use.
They said the fix is to replace the ignition switch with the respective
key set since that is the trigger of the no start event.

 

does your security light come on when urs malfunctions

 

ive got a 91 camaro that has been to every shop in town replaced dam near evrything but the security sytem it hasnt fired in 2 years its a barn queen now no 1 can figure it out and this is the same setup9which i think sucks) my ? would be would the security sytem ,key .ingnition tumbler ect. malfunction with no security light flashing or on when i crank it

 

p.s. vats sucks

 

No security light ever comes on with this one and even the dealership couldn't discover
the problem. It only happened to them once and even then they couldn't trace it down.
However, the article I read about the problem on a different forum mentioned the problem specifically and it really rang a bell.
This is my best guess, that the ignition switch and related key is the cause.
From the descriptions, that's what it is leading me to conclude.

The only difference between what you described and mine is that my Vette doesn't even
crank until the 4 minute timer has reset.

 

When it won't start, THAt is the time to start diagnosis. Engines require spark, fuel, air, and compression in order to start and continue to run. You need to test every one of these points to find out why it won't start. See if there are any stored error codes. Use a timing light to see if you have spark. Pull a plug wire and bring a grounded wire near the plug boot while someone cranks, you should have a snappy at least 1/2" spark. Measure the fuel pressure, it should be 35-42 psi and it should hold up with the ign off. Use a noid light to see if the injectors are being pulsed during cranking. Use starter fluid and see if it will start and if it does, you have a fuel delivery problem. Since the engine will run after a wait, I doubt you have a cylinder compression problem.

 

When it won't start, THAT is the time to start diagnosis. Engines require spark, fuel, air, and compression in order to start and continue to run. You need to test every one of these points to find out why it won't start. See if there are any stored error codes. Use a timing light to see if you have spark. Pull a plug wire and bring a grounded wire near the plug boot while someone cranks, you should have a snappy at least 1/2" spark. Measure the fuel pressure, it should be 35-42 psi and it should hold up with the ign off. Use a noid light to see if the injectors are being pulsed during cranking. Use starter fluid and see if it will start and if it does, you have a fuel delivery problem. Since the engine will run after a wait, I doubt you have a cylinder compression problem.

 

well, if it won't even crank to begin with due to a security lockout timer event,
it won't be of any use to try checking for other things such as spark, etc... etc...
So, to even crank, they first require power and the lockout event prevents that.

The primary purpose is to find out why the security system has triggered
and thus causing a "no start" condition.
I'm quite positive once the timer event has elapsed, the car starts up as though
nothing was ever wrong. So, all the other investigations are a waste of time.
No offense intended, but dealerships have made fortunes off of this.
Lastly, never ... NEVER use starting fluid unless you wish to damage your
cylinder heads and pistons.