FAD2BLK93

Ok guys heres the problem,. Had the car tuned after 503 install. Cold start is 1050 rpm, no problem, then i start driving everything seems good. Then i come to a red light, gotta throw the car into nuetral cause brakes arn't so good with the low vacuum. Idle goes up to 1600-1700 rpm rolling to a stop, and stays there till i come to a COMPLETE stop!! Then the idle will gradually come down to 850 in nuetral. (800 in gear). This problem does not change if the car is cold or warm, rollin down the freeway at 60 or motoring thru town. If the car is moving and u put it in nuetral the RPM's go up and stay there till i STOP. my tuner thinks it is either vacuum leak, IAC or TPS. Well here are the numbers. No vacuum leak did a smoke test and had no leak, IAC is at 54-59, and TPS IS AT .61 and 0%, 1% throttle bade opening is at .67 on this sensor. Out of these 3 things that they suggested i see no problem!!! I dialed the TPS back from .63 and it is totally off the throttle stop screw, and now i have a slight hesitation. Which i think is caused from the gap between the .61-.67??? Is there a tuning catagory for RPM vs wheel speed? Is this a tuning issue? Every adjustment i have made has not chaned anything!!!! They told me to send it back and they can adjust the idle from 800 to 700 where i want it, since i dont have a stall, 800+ just pulls me down the road. I can do 35-40 with out even touching the gas. HELP im really pissed off and my car is no longer fun to drive. I have been offered a 96 z28 with the LSswap already done, thinking seriously about that one. Can anyone HELP ME PLEASE! THANKS, Marc

ny_z28man

iTrader: (2)

The engine is getting air from somewhere to keep the idle up, if there is no vaccuum leak the the trottle body is probably allowing this extra air into the intake. If the numbers are good I would check for a mechanical problem with the trottle body.

FAD2BLK93

This is a 93 car, so there is no MAF. so the rolling to a stop with a high idle, u think is caused by unmetered air into the intake? The thing that gets me is, when i blip the throttle in park or nuetral the idle does not hang upward and then drop. But if i am in gear and i put it in nuetral the rpm's will go up to 15-1700 then come down. Make sense?

ny_z28man

iTrader: (2)

The only thing I can think of is unmetered air and a mehanical failure if all your elecrtical sensors are showing correct and within limits. Search for the relearn procedure for your IAC just incase that is throwing the idle off. If I were you I would be searching the throttle body area including IAC. I dont know if you can check your IAC activation while your driving with your computer but if you can check it out.

FAD2BLK93

I can check it while driving, it fluctuates up and down as i am driving. Is there some target number i should be looking for? I will look at it and see what it does when i put it in nuetral when the car is rolling. I did NOT have this problem before the tuning after the cam swap, and the TB was never off. This makes me wonder if there is a tuning catagory for RPM VS WHEEL SPEED? i have seen other threads with the same problem. The problem is no one comes back to follow up on the threads, to tell everyone if and what fixed there problem!!! Tuners please chime in! Keep in mind this is a 93. Thanks. Marc

FAD2BLK93

Bump...anyone have any other thoughts about it? Im about to send the tune back. Would like to know how to comunicate the issues i have been having. Just read another post that said to tune for open loop operation, my car is a 93 obd1. Would i benefit from open loop? What are the pros and cons? Why do this? Thanks

grazi

Just a thought and I may be way off. The reading you are getting from IAC, Is the reading directly from your IAC at idle or are you datalogging? If datalogging,Is it posssible that the OHM reading you are looking at is what the computer is commanding it to be at and not necessarily how open the IAC valve is? (A weak spring or dirty IAC)

guppymech

iTrader: (7)

On both of my modern fuel injected manual trans cars ('02 Saturn SL and '94 TA) the idle stays higher when moving with the trans in neutral, not quite as high as yours though, about 1100 or slightly higher. When I come to a stop they will drop down to idle speed. I think this is something GM engineered into the pcm. GM never intended the A4 to be driven the way you are using yours. The trans and its controls were designed to be left in drive. Do you know anybody with a more stock car that could try what you're doing and see what the results are. Personally I don't think you have a problem, your 800 rpm idle is good.

FAD2BLK93

Not quite following u there. But i have a Mac Taskmaster tech tool. I am reading live data from the OBD1 port. My IAC is set at .61, and 0% throttle opening. .67=1% throttle opening. So now i have kinda a hesitation from the gap between the space before throttle opens. Gonna bring it back to .63 again, maybe higher.

FAD2BLK93

800-850 to me is kinda high without a stall. The car drags me around town at 35-40 mph without even touching the gas. I think 700 would be better, and it would bring out more of the lump in the cam. My IAC is new...i thought the old one might have had a problem so i changed it out, nope same problem. The other cars i can look at are a 2000 ls car and a 02 v6 car. I will check it out. Thanks