Tuning

Slowray32

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I have a question about getting my 1993 viper tuned, when I purchased it last year, it had already had the heads , cam, roller rockers, exhaust, and headers done, it had a broken oxygen sensor on the right side, so I replaced both with oem parts, the car runs good, only thing is that when braking heavy with clutch in and coming to idle it sometimes stumbles and stalls, so my thoughts were that it probably wouldn’t hurt to have it tuned properly, it also seems a little rich to me, the previous owner had gen 2 injectors in it when the engine was built, and it now has the gen 1 injectors back in it, and definitely took some of the richness out of it, I’m a diesel mechanic for a living, and just want the car to be correct, I’m looking for someone on the east coast to bring it to and give it a good tune and once over. Thank you in advance
 

MoparMap

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Do you have any idea how long it has been since any engine changes? I know on my gen 3 at least the engine actually learns the idle position over time. I did a fresh rebuild with an updated cam and the first several drives it would die at stops until the computer learns the IAC position it needs for idle. I don't know if the early computers are the same, but you might just drive it around some more and see if it fixes itself. I think it has to be up to a certain temperature and stuff as well for it to start figuring things out. If it's been doing it for a long time though then I'd agree it sounds like a tuning issue.
 
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Slowray32

Slowray32

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It’s been driven probably a thousand miles or so, it’s not really to bad, I just want my wife to be able to get in and drive it without ever worrying about it ever stalling, it seems like if the idle was 100 or so rpm higher that it would take care of it, I think due to the large cam, when you brake and have clutch in coming to a stop light it just looses a little to much vacuum at idle, but I believe the only idle adjustment is in the ecm.
 

GTS Dean

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The IAC pintle may be gummy and unresponsive to step signals. You can run an IAC Wiggle Test to confirm it is stroking properly. Use the right kind of spray to clean it.

One other possibility is the throttle cables out of synch. If this happens, the IAC can't manage airflow even at zero step.
 
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