on a cold start (overnight) i have to hold my engine at 1500-2000 rpms for sometimes up to a minute before it will hold an idle...when i started it after my rebuild for the very first time, i had my scanner on it and my iac motor wasn't even working for the first 5 minutes or so...so it wouldn't idle, then after 5 minutes i got response from my iac and it would idle...

on a cold start after i hold the rpms up for a minute or 2, after that it will run/idle just fine until i start it again cold...what could my problem be? also it seems to be running very very rich during that "warm up" time also. if i start it for 5 or 10 seconds and it doesn't get "warmed up" it is REAL hard to start again unless i let it sit for like 10 min.
and one time i tried to start it cold and just drive it immediately and it almost broke my damn neck cuz it was jerking so hard.

engine is a forged 357
le2 heads, custom cam (lil larger than gm847)
tune is by madwolf.

thanks for any help
-Jason

 

Did you have it tuned? I'd put a tuner on it and see what values it's actually spitting out before warmup and if it's tuned properly.

When the engine is cold, it's using open loop and stored values for air/fuel. When it warms up, it's using closed loop and the oxygen sensors to calculate air/fuel until you really step on it... then it's back to open loop.

Just a thought.

Mike

 

What injectors are you running, by chance?

 

i don't have a "tuner" but i have a gm scanner what values do i need to look at? look at them durring open loop, then compare to closed loop?
tuned by madwolf


i have accell 30#

 

If its possible, swap our those Accels, for another brand of 30#'s, like SVO,Lucas,etc...

 

could that be the problem? i did an le1 package last summer and put the injectors in at the same time and they worked great for me all last year, and i never had this problem.. and i reused them after that engine threw a rod and i built this one. i heard that svo's are the best, but i also heard that accell's were the easiest to tune.??

 

I think they might part of your problem...The repeated, hard starting issues could be the injectors...I had the same injectors, and I had a hard starting issue, that I swear up/down, it had to be them...Leaky injectors can cause this..I eliminate them, just swap them out for another set of 30#'s, and see what happens...(its not that hard.)

 

oh i agree it won't be hard to do..just gonna cost me, i could sell my other injectors but i'm gonna loose money on the deal. and i owe a few grand on the engine to begin with. any links where i could buy those svo injectors?
i just don't understand why it didn't do it before on the other setup..

 

Have your tuner look at the file again, and verify your IAC is working properly. Did you replace the IAC or do the reset procedure to it? I believe it's hold the throttle part way (10% maybe?) and start the car. If it's running rich and won't idle, I'd suspect the tune...my car idles like a kitten even when cold on first-start. I was having a rough idle on cold start and recently went back to my original tune and all is fine. The tune can make a HUGE difference.

 

You have an open loop tuning issue. Check the injectors, but I'd bet on the OL tune.