This one has been pulling my hair out. Cant fiqure this out for the life of me. Car is a 1996 Camaro Z28 LT1. The car always runs perfect. The problem is if you shut the car off, run into the store for 15 minutes, come back out, the car will crank for an extended period of time (longer then normal!) and then start. It runs fine, just takes longer then normal. After the car starts hard starts once, if you shut it off and restart it, its fine.
It only has the problem the first time you start it, after sitting for a few minutes. (heatsoaked)
-The car runs fine always
-The car cold starts fine
-It only does it one time after a heat soak. If you shut it off after it messes up and allow it to sit for another 10-15 minutes it will do it again
-Car does not smoke or run rough when it hard starts
-Car just had an optispark (twice), water pump, injectors cleaned (twice) and intake manifold job done. The reason I put twice there is because I thought the problem may lie in one of those areas, but so far nothing.
-Changed the module and coil thinking maybe a heat soaked electronic part. Nothing
-Fuel pressure stays pretty consistent, it does not got to zero once the car is shut off, the system will hold pressure for a couple of hours.
So far everything I have checked and changed has not changed the problem one bit.
Any advice? Tips? Etc? Need more info? Anything would be great. I am at a serious loss here. Thanks in advance!! Dave
You seem like you've been checking everything diligently. Seems as if you ruled out fuel and spark as the culprit. Any chance it could be a voltage problem? I know it's a long shot, but I would check the voltage at the starter/battery when the car is acting up.
__________________ '98 Z28 M6 silver hardtop, intake, full exhaust, gears.
I had something like this goin on with a caprice 9C1 and it seemed like the oil pressure cutout sending unit/relay was not letting the car start until the motor generated oil pressure mechanically high enough to allow the relay to operate the Fuel pump but after changing a bunch of parts etc all that was really wrong was the ground going into the under hood relay/fuse box was bad, made a jumper ground wire and it fired right up every time, cost me a bunch of relays, a fuel pump and full ignition/tuneup stuff but at least I learned something...
That sometimes (as I have noticed) has an affect on starting when it's warm. I moved my battery to the back and it started having the exact same symptoms he is having -started fine cold, ran fine, just had an extended amount of time to start once it'd been warmed up.
__________________ '97 T/A LT1 So Slow. Awaiting Teardown
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IMO, check the ICM. All electrical components are susceptible to heat, and the ICM is one of the hottest. They are known to fail when hot. Swap it out with a friends car, or just replace it. Then mount it further away from the head.
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If it has a tune or anything like that (ie fairly modded). You can up the 1st prime pulsewidth for the hot start by 1.6 (min change for this table iirc) or so and it should shorten the cranking time usually. Makes it kind of spunky if thats what it wants and when it lights and it will usually go to 1500rpm for half second or so. I wondered what that table did and one day I just decided to test it out first removing fuel and man crank crank crank then it fired finally. Moved it the same amount the other way yikes fired right up when it was hot just like on a cold morning. If you got spare time to figure it out you can even tweak the initial afr correction to make it even better. All you have to do on my car is look at the key and it starts.
i had this same problem and i did a combination of replacing the battery and the starter and it was fine after that. i agree, i think the starter was getting heat-soaked, and the battery was pretty old so i just changed both and its all good now
__________________ throttle heating bypass, heater bypass, a/c delete, Soon:LE2 heads, custom grind cam, 1.6 pro mags, comp rollers, custom exhaust with cutouts, pacesetter longtubes PHK In the 808