This spring I started having a cold starting problem with the car. First it started out as taking a long time to crank before turing over, but eventually it would start. Then after a month or so, the car would crank and crank but not start, but only when cold or on wet days. Sometimes it would sputter ONLY after the car has stopped cranking, but never actually start. One day through troubleshooting I switched out my tuned PCM (OBDI Converted) for my old un-tuned PCM (Original OBDII). After doing this, the car started right up. I don't know why it worked, but it seemed the old un-tuned PCM started the car cold, then after the car would warm up with the old PCM, I would switch back in the new tuned (OBDI converted) PCM and it started and ran fine after it was warm. I still didn't think it was totally the PCM, so I had changed a lot of things in the mean time that might have affected the starting (Coil, plugs, wires, Opti, Fuel pump, and Crank Position sensor). I also have an MSD 6AL ignition. All of those things seemed to help for about a day, then it would go right back to having the problem, almost always on really wet days. The rain might possibly have something to do with it, but the car still scold tarts fine with the old un-tuned PCM, then when warmed up, the new PCM starts fine.

Can anyone help me out with this problem. I haven't talked to anyone that can figure it out.

TIA

 

I would check the fuel pressure to make sure it is not bleeding all the way off after the car sits for some lenght of time. It may be the fuel pressure regulator. Sounds like you have covered everything else. Hook the guage to the return line valve.

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

 

I have a FP guage inside the car, and it does do somthing odd. It seems to only pressureize up to about 32 psi cold, but when I get it started with the old pcm, the pressure stays at 40-43 psi. If it is the FPR, why would the old pcm start the car cold?

 

I had a tune somehow get messed up on me and it took me months to figure it out. I think it was data corruption because at the time tunercat didnt have those tables available to change..It turned out that one of the cranking enrichment tables got zeroed out at 68 and 80 deg celcius. If the car was at that temp the injectors would not fire!!!! Just a thought that might help..

 

That sounds interesting. I had a OBDI conversion from Madz28.com. I sent Ion an e-mail but I'm waiting to hear back.

 

No one else can help me out? I really need to figure this out. It's my daily driver.