I have a '93 Z28 LT1 which normally runs reliable and trouble free. Actually, it still runs fine but suddenly the starting went from touching the key to having it turn over and over and over until it finally fires. Sometimes when it does it sounds like it's choking for air or gas and if I touch the gas pedal it revs up for about 15 seconds until it goes back to normal. Once it starts it runs great and starts great unless it's turned off for more than 5 minutes. I've always had carburetors and this is my first FI car so I don't have much experience and knowledge. I should add that this problem exsisted on a smaller scale when I bought the car and when I added the cold air induction it became a touch the key starter. I thought it was a result of the better air flow but apparently not. If anyone can give me some suggestions it would be greatly appreciated. I should add I am not getting any idiot lights or trouble codes. Thanks.

 

Extended cranking times can be caused by pressure bleed down in the fuel system. The pump only primes for about 2 seconds, then shuts down. If pressure drops rapidly, it's going to take longer to start. One simple test is to cycle the ignition key back and forth several times from "run" to "off", before turning it to start. If that shortens the cranking time, your fuel system is losing the prime pressure.

Another way to test it is with a fuel pressure gauge. Turn the key to "run" and observe the fuel pressure at pump shutoff. Should prime to at least 40psi, and bleed down very slowly. If it bleeds down rapidly, you found the cause of the extended cranking. We can proceed from there with the possible causes of rapid pressure loss.

Another possibility is leaking fuel injectors. That will not only cause rapid fuel prime pressure loss, but can flood the cylinders. To check for this possibility, before turning the key to "start", put the accel pedal on the floor, and hold it there until the engine starts. That puts the ECM in "clear flood" mode.

 

I think it's the first item, the lack of pressure at prime. Unfortunately I don't have a fuel pressure gauge but will check the pressure when I do and get back to you. Thanks again.