Justin11141

Bought a z28 a couple of months ago. Changed air filter, oil, and oil filter and it was running fine. Then there started being long crank times but not too long (maybe 1-1.5 seconds) only on cold starts. Suddenly it got really bad and now it sometimes takes a good 1-3 seconds to get it to start and sputters. Then when it starts there might be a rough idle or smoke might come from exhaust but its really light. Also the smell of gas from the drivers side when I get it to start. Could it be signs of a failing optispark or anything else ?

parkers Z28

What year is the car ? any lights on in the dash ? have you had someone scan for codes ?
did your oil have a gas smell ??? leaking injectors could cause a hard start when cold

I think there is a sensor that reads the outside temperature which tells the computer if choke is
needed ??

Justin11141

Its a 95, no lights anymore I fixed the coolant sensor light recently bit that's it, also it has a hard start even if not cold

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bobdec

Try this- turn key on w/o starting engine for 3 seconds, then turn key off repeat this two more times. You should hear the fuel pump prime each time the key is turned on. Then try to start it. If it works then you have a leakage problem loosing pressure in the rails when stopped. If it starts with black smoke then the leakage could be a dripping injector, if it starts and runs normally then the leak may be a check valve in the fuel pump. I would recommend verifying fuel pressure if you can get hold of a gauge.. Search on " LT1 fuel pressure leak down " for more info if the on/off test works..

Justin11141

Thanks for your reply but it was no different any chance it could be spark plugs?

Edit: think its a leak now, I floored the gas pedal and it started almost instantly

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Injuneer

Holding the accel pedal on the floor when you try and start it puts the PCM in "clear flood" mode. That may indicate a problem with leaking injectors or a faulty coolant temp sensor. I assume the "coolant sensor" you fixed recently was the coolant level sensor, since you mentioned a "light".

Have you scanned it for codes?

Justin11141

I was going to at auto zone but they said I needed the check engine light on for it

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Injuneer

Find a shop that knows what they are doing. Once a code sets, it is stored in the PCM for a decent period time, even if the problem goes away and the SES light goes out. There are also codes that don't even turn on the SES light.

Make sure the shop knows that even though your 95 has a 16-pin ALDL connector that looks like an OBD-2 connector, the PCM is OBD-1 and they have to use an OBD-1 scanner, the correct cable, an adapter plug, or jumper the wires as shown on Shoebox's site.