Cammed LS1 likes to stall with AC on
06-13-2014, 02:34 PM
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Cammed LS1 likes to stall with AC on I recently had a 228R cam installed in my 02 Z28. It's been tuned by a local shop, not sure if I'm allowed to say who. But anyway the first time they tuned it, everything was mostly fine except the rpms seemed to dip down pretty low when I pushed the clutch in when coming to a stop (like 3/400 rpm) and then shot back up. This was exaggerated when the AC is on and it would stall the motor. If I was just idling and then turned the AC on it was fine, the rpm would bump up a bit. But it's mostly when coming to a stop with the clutch in.
I took it back to them to have them fix the problem. He did this by (from what he told me) bumping up the idle a bit and adjusting the timing. It seemed to help, but I just drove the car earlier today and I had to press the clutch while in 2nd as I was slowing down and the damn thing stalled on me. Then continuing to drive, it seemed like every time I slowed down to a stop the motor bogged down almost to the point of dying again.
Basically it drives like **** with the AC on. And I have already taken time out of my job to go back there once for them to fix the problem they didn't do the first time around, which would be fine had they actually fixed it. So what are your suggestions? Take it back again? Find another shop? It's not even a big cam, and I honestly loved the way it sounded at stock idle but now they have it bumped up to 850 I think (875 or 900 with AC on). Is it not possible to have a stock idle and not drive like complete ****?
I took it back to them to have them fix the problem. He did this by (from what he told me) bumping up the idle a bit and adjusting the timing. It seemed to help, but I just drove the car earlier today and I had to press the clutch while in 2nd as I was slowing down and the damn thing stalled on me. Then continuing to drive, it seemed like every time I slowed down to a stop the motor bogged down almost to the point of dying again.
Basically it drives like **** with the AC on. And I have already taken time out of my job to go back there once for them to fix the problem they didn't do the first time around, which would be fine had they actually fixed it. So what are your suggestions? Take it back again? Find another shop? It's not even a big cam, and I honestly loved the way it sounded at stock idle but now they have it bumped up to 850 I think (875 or 900 with AC on). Is it not possible to have a stock idle and not drive like complete ****?
06-13-2014, 03:27 PM
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Adjust your idle screw, the IAC count is probably too high. By threading the screw up, it will open the throttle plate slightly at idle and it won't rely on your IACV as much.
06-13-2014, 04:05 PM
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As much as I'd like to say take it back again, personal experience with other 'professional' local tuners over a decade would make me a hyprocrite.
I've been fighting the same situation without help of the pro tuner I used back in February who left me hanging. Yeah, try to get your IAC's around 60-70 at hot idle, AC off, by adjusting the TB screw that the cam rests on. If you move it too much you'll need to perform a TPS reset to keep your TPS at 0% at idle. Perform a RAF calibration and if you're having instability before it enters closed loop then, add maybe 1g of additional airflow at the 140* cells and below per driving session until it seems reasonable, shouldn't need more than an additional 4-6g total if I had to guess. It also seemed to help me when I mimiced the stock 400RPM VE column... I ended up making my 400RPM VE column about 85-90% of my 800 RPM column. Fiddling with the throttle cracker and throttle follower never got me anywhere, but it seems to have helped others... I never truly understood how to calibrate those tables. If you manage to get it resolved, make sure you post the resolution
I've been fighting the same situation without help of the pro tuner I used back in February who left me hanging. Yeah, try to get your IAC's around 60-70 at hot idle, AC off, by adjusting the TB screw that the cam rests on. If you move it too much you'll need to perform a TPS reset to keep your TPS at 0% at idle. Perform a RAF calibration and if you're having instability before it enters closed loop then, add maybe 1g of additional airflow at the 140* cells and below per driving session until it seems reasonable, shouldn't need more than an additional 4-6g total if I had to guess. It also seemed to help me when I mimiced the stock 400RPM VE column... I ended up making my 400RPM VE column about 85-90% of my 800 RPM column. Fiddling with the throttle cracker and throttle follower never got me anywhere, but it seems to have helped others... I never truly understood how to calibrate those tables. If you manage to get it resolved, make sure you post the resolution
06-13-2014, 05:19 PM
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Thanks for the input guys. I talked to them and they said it's possible that there's an issue with the IAC valve but I will suggest what I've read here and tell them I want a stock idle. I'm taking it back there Monday or Tuesday. And I don't mean to paint them in a bad light or anything, they're a big reputable shop around here and I've dealt with them before and had no issues and they are always polite and helpful. But we'll see. I'll keep you guys posted.
