Its an 87 IROC with the LB9 V8 and a 5spd. Last week I installed my chip I ordered from FastChip (nothing special, just the stage 2 chip) and I installed the 160 thermo thats required when running a stage 2 chip. The improvements are noticeable and all is well: it idles smoother, its more responsive, it pulls harder at the top of every gear, and it even runs a hell of alot cooler. However, I have one prob: first thing in the morning when I start her up, I'll wait till she drops her idle, which takes maybe a minute sometimes less, before I start driving but the car seems to stutter a little for about 5mins or so and then the car is perfect. I thought the car would drop idle when it was "warmed up" but it seems that although it does drop, the car doesnt really "warm up" for another 5 mins or so. I'm not exactly sure what the heck it is. Do u guys think the chip has anything to do with it or is it just a coincidence?

 

The chip may have brought out the bad in some stuff or the program might be wrong or not quite right. Try this first. Get a scantool and run the car till it is in closed loop and all that. Maybe you can do this without shutting the car off after you come home. With the car idling and out of gear, hook up the scantool and see how many counts you have for the Idle Air Counts. Should be around 20-30 and then the ECM can adjust properly.

[This message has been edited by aklim (edited August 30, 2002).]

 

I'm not sure if this makes a difference or is just a typo of some sorts but, an interesting thing that I noticed about the chip is: when I ordered it, I told the guy on the phone that I had a 305 cuz he assumed I had a 350. When I got the chip, it said on the receipt that I ordered one for a 305 but on the chip itself, it has the PROM code that I specified (which was listed on my stock cpu) and it also said 350 next to the code. The car runs great except for the stupid stuttering thing when its cold. What gives??

 

anyone???

 

We need the idle air counts to know. I believe that your counts are not in the right range. When they are right, you will need to reset the TPS. Shoulda gone to www.fasterproms.com because they will tell you what the timing and TPS and what you need to adjust will be. They are also capable of loaning you a diacom to make improvements from the setup you have.

 

I'm afraid to tell you but almost all cars will not run their best (especialy at low-rpm) until the engine is at about 140 degrees. My 305 TBI ran surprisingly good when it was cold but my current sutep has a pretty bad low-rpm stutter when it is cold. But that is expected. I'm not really mad about it. I'm sure I could tune my carb up a little but overall, it's an engine. I'm happy with it. Not everything can be absolutely perfect. Your car is probably ok. Just don't get on it very hard until it's fairly warm. The best temperature for an engine is about 160-170 degrees.

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92 RS carb'd 357 5-speed T-tops maroon w/ black cloth interior
650 cfm Double Pumper, stealth intake, dual 12" radiator fans, 10" auxiliary pusher fan, 5" X 12" power steering cooler, 204/214 cam duration @ .050", 420/443 valve lift, 1.75" headers, no cat, 3" PaceSetter catback w/ dual 2.5" tailpipes, 3.73 gears, posi, 245/50/ZR16's up front, 255/50/ZR16's in back
2.070 60 ft, 9.9 @ 71 (1/8), 15.4 @ 87 (1/4) <--old times
100% American (you damn right)

 

I beg to differ. My car starts up and runs in the cold weather and warm weather just fine with the stock config. After I got my new EPROMS, they still run just as good. It is a matter of tuning it. I sent the cold start, warm start, cold idle, warm idle, cruise and WOT diacom runs and they have been fixed.

You cannot just make one burn and expect the chip to be perfect. Mine was the result of a couple of burns to get it just where I want it. They made the rough one and then improved on it.