Ok I got the car running a couple of weeks ago but I was finally able to get it onto the ground. I am running a built 4l60-e with a brand new gm converter. I choose it for reliability because of the miles it will get put on it and it is a 100% streetcar. Now for the problem. I had the computer custom tuned by a shop in San Antonio. It has all of the normal bolt ons and headers. The car idles at 700 give or take 50 rpm throw it in gear and it will die every time unless you feather the throttle. We adjusted the idle set screw so it could be driven for test. The IAC counts are zero desired is about twelve. On heavy throttle take off or on a downshift it smokes black out the exhaust. I took the pcm and gave them the specs of everything since the car was torn down at the time. Is all of this a tuning issue and I just need to take them the car and let them see what they need to do in order to alleviate the problem. They said no problem I just want to go armed with info. Or do I have two problems tuning and too tight of a converter for this cam. Once it is going down the road it pulls hard and has no kr anywhere. Just rich smelling exhaust and a dying problem at stock idle setpoint and in gear.

 

Anyone even had this in the past?

 

I have the same problem as you do, black smoke on hard take off and trying to die in gear (It never has died though, just seems like it is trying too). I am using a PCMforless tune too. I figured the tune was not as good as it should be but I don't know if that is the issue now since you have the same problem as me with a custom tune. I am also running a 2400 stall with the hotcam. If you find out the problem, please let me know something.

 

Will do it sounds as though i am not the only one here.

 

well, the dying and IAC counts point towards the IAC. all the black smoke could easily be because of the tune.

i knew my IAC needed replacing a while back. i did my cam swap still with the auto and it didn't change too much. my auto went about a month later and i swapped to a t56 and the problem was magnified many many many times. the car would die sometimes putting it into gear, but really where it died the most was when i was decelerating and pushed in the clutch. changed out the IAC and the problem went away.

i would have said it could have been all tune, except for those IAC counts.

what year is your car? if it's an OBDI car then send me an e-mail to roadrage912@hotmail.com and i'll see if a friend of mine will datamaster your car if you're still in college station. he's done with finals tomorrow and is staying in town part of the week. he might also have my old auto/hotcam tune that you could toss on there and see what happens.

 

whats an IAC

 

IAC=idle air control (valve)

 

IAC valve is located under the Throttle body. THose things can get seriously gunked up over the years. It's pretty easy to clean the passages and everything down there. and last time I checked IAC counts "desired" are supposed to be in the high 20s to low 30s. Not Zero..

Matt

 

Roadrage. The IAC was capable of keeping the car idling the couts for actual and desired matched within 1 count. It zeroed the actual when I adjusted the idle up using the set screw which makes sense. I did not clarify real well on that one. It is an obd2 car so from what I am hearing it sounds as if the tune is off. Is this also causing the dying problem when I drop it in gear or do I just need to have the electronically raise the base idle. It just sounds so good idling slower but I guess it's not worth a damm how good it sounds if it dies when you throw it in gear. thanks guys

 

Roadrage. The IAC was capable of keeping the car idling the couts for actual and desired matched within 1 count. It zeroed the actual when I adjusted the idle up using the set screw which makes sense. I did not clarify real well on that one. It is an obd2 car so from what I am hearing it sounds as if the tune is off. Is this also causing the dying problem when I drop it in gear or do I just need to have them electronically raise the base idle. It just sounds so good idling slower but I guess it's not worth a damm how good it sounds if it dies when you throw it in gear. I had it tuned at fuel injection specialties in san antonio. They said bring the car and they will correct it if it's the tune. I am just trying to be damm sure. The motor and trans are a fresh build. with about 20 miles on it. thanks guys