karpetcm

As stated in another thread the car takes 10-15 cranks before it starts for the first time or when it sits more then a few minutes. When you start it up right away it starts up much faster. Today i noticed when i was filling up gas that alot of air was hitting my hand from the nozzle, the gas nozzle has two vent holes at the top of it and ive honestly never noticed this much air at all hitting my hand so it was very unusual.

Just a little about the car it has new plugs, wires, coil, opti and maf. Also to rule out battery and alternator they were test and we also tried jumping the car just for the hell of it in the begining of diagnosing and it started up 10-15 cranks later so the problem was still there. My mechanic thinks its ignition, i dont think it is the car pulls strong and hard through the rpms with no hick up at all. Only options im thinking is something with the gas tank maybe the evap canister not sure, afpr but im pretty lost at this point and 2 different mechanics are not able to figure it out either.

parkers Z28

check the fuel pressure ...
Next time it does it turn the key back and forth and see if it starts faster
when your doing this your not trying to crank the car your cycling the key
to engage the fuel pump on and off and then crank the car

karpetcm

Hi parkers Z28,

Ive done that method it doesnt start any faster by cycling the key. It will just start faster after the first start up. If it sits more then a couple of minutes it will take long to start but if i start it up right away after the first start it will start up much faster. Cycling the key has no effect i wish it did though might of been easier to diagnose and less headache.

Injuneer

Does the engine smell flooded? If so, hold the accel pedal on the floor before you turn the key to "start", and hold it there while it cranks. If is starts quicker its flooding, possibly a leaking injector. And you still need to check the fuel pressure.to see how fast it drops after the pump shuts off.

You mention an "afpr". Do you actually have an adjustable fuel pressure regulator?

On the other hand if it doesn't smell flooded, you may have a problem with the coolant temp sensor not indicating the engine is cold. That would prevent the PCM from richening the A/F ratio for cold start.

Just some possibilities.

karpetcm

Hi Injuneer,

Actually thats my bad i just have the stock fuel regulator. The car even if i put the pedal to the floor and start it does the same thing as well. I will for sure check the fuel pressure, i actually havent thought about checking the coolant temp sensor i will look at that as well.

alex-z28

Hi,

I got 93z and I got exact same problem, down to a lot of pressure build up in the gas tank to the point where my fuel pump would whine so hard you could hear it a block away. I would have to turn the car off and open the gas cap to release the pressure, and then it would be fine. I should mention that happened to me only few times though and I don't remember last time it happened. I think that has nothing to do to your long start problem, that is a another issue.

I made threads before and got same advise as you and still I was not able to find answers.

I replaced the following

plugs and wires
injectors
ignition module
coolant sensor

Nothing helped. I have played around for years, I would check one thing or replace one thing and still nothing so I would get pissed off and forget it for another year and so on. I didn't want to take it to the shop and get huge bill for it, since it was not a big deal for me anymore.

Then finally, my buddy who is a mechanic who had no answers as well prior to this had me come over to his shop and do some more testing.

He found out that when it was hard to start, the car had no spark or injector pulse. He is not 100% sure because he has not worked on many LT1s but he is certain that its opti spark.

So while you are looking at above, check to see if you have spark when its hard to start. I know that you replaced the opti but still.

Also, do you have hard time starting when the engine is cold? Mine would only have hard starting issue when the engine is warm.

I store the car for 5 months it starts right away, I try to start it after 15 mins of shutting it off it cranks forever.

Good luck.

Injuneer

If the loss of injector pulse was due to the optical cam position sensor in the Opti, you should have code DTC 16 stored in the PCM (OBD-1) or P1371 (OBD-2). Those codes do not turn on the SES light.

As always, first thing to do when you have a problem like this is scan it for codes. That's extremely easy on the 93.

alex-z28

We checked for codes, my buddy used Snap On scanner that they use at his shop, there were no codes. So, I don't know maybe try another scanner?

Also, what would cause no spark issue?

Injuneer

You don't need a scanner to scan a 93.

http://shbox.com/1/dlc2.jpg

If the ECM doesn't get the cam position signal on the startup attempt, it can't set the ignition timing.

alex-z28

Just tried it and no codes. It keeps flashing 12.

I have bought new opti, just didn't get to install yet, I was gonna do it this spring hoping it was going to fix the problem, but if its not the opti then what could it be Fred? Could it be the opti even though I am not getting codes that I should (code 16)?