car dies with AC on
06-19-2008, 08:13 PM
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car dies with AC on Alright, I did iEGR and iAIR a while back when i did my H/C swap on my 2000 Z28. Ever since then, my car has had a rough time starting. I'd have to keep my foot on the throttle a little bit until it will actually idle properly. Today, i put the AC belt back on cause it's hot as ***** outside. I went to start it up and turned on the AC. The AC was really cold but only blew out of the top vents. Also, i sat in the driveway giving it gas and trying to keep the engine from dying for about 5 minutes then gave up. As soon as i let off the gas, the RPMs will just drop to 0 within a couple seconds. So this makes me think i have a really bad vacuum leak, especially with the AC controls. Does anybody have a picture of the vacuum connections after an iAIR mod or any other recommendations. It's driving me crazy, thanks.
06-19-2008, 10:15 PM
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yup sure did, got a good dyno tune from the main LS1 tuner in the area. i had him take a look at everything on my ecu right after i noticed it happening. he tried to change a few things each time i took it back. he had no idea of what it could be if it wasn't a vacuum leak.
06-20-2008, 05:48 AM
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sounds like a tuning issue to me being that you have to play footsy with it to get the ideal to smooth out my TSP giant cam did that until i got a good tune on it... It still has a little loop to the ideal but i can start it and throw her in drive and go now wheres before it would just die. not saying that your tune is screwed up but some tuners are better than others and some cams are more forgiving with some setups rather than others... what is your buildup .... as for ac good luck only way i know of any one having it run right is to turn it on when your rolling at a good speed and turn it off when you stop hahahah sorry bro thats the nature of the beast
06-20-2008, 07:02 AM
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^ ha sounds like you had the same problem as me. turning off the AC right before i disengage the clutch is the only way she'll stay alive. as far as my buildup, i have: TEA 5.3 liter stage 1.5 heads, Futral motorsports F13 cam, longtube headers, fluidampr harmonic balancer...and that's about it as far as mods that would have any sort of affect. i have a 92mm intake manifold going on pretty soon with a wilson 90mm TB. damn i was really hoping it wasn't my tune. but come to think of it, it's alot harder to start when it's raining or just cold outside. thanks for the help
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06-20-2008, 03:28 PM
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If you had it tuned with the AC belt off you may have to have it re-tuned with the belt off. It may just drag on the engine enough to cause that problem, only guessing though.
06-20-2008, 06:41 PM
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huh well i sure appreciate the help guys. for those of you that had the same problem, did you end up getting your cars to idle properly after a re-tune or is it something i'm just going to have to deal with?
06-21-2008, 01:18 PM
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the ac thing your just gonna have to live with as for fondling your gas pedal to start the car that's a tune issue... im lucky my local tuner will spend all day till its right for 250
06-21-2008, 01:45 PM
#13
my car did that for a while... it was tuned for a straight week trying to figure out the issue. Apparently after we made the throttle body hole slightly larger, it fixed the issue... when you have all this motor work done to your car the engine requires more air at idle to run properly, especially with the A/C on.
06-21-2008, 03:09 PM
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okay this is all starting to make more sense now. i just realized the ac actually blows properly through the floor vents as well as through the top vents as it should. i now 100% believe that it's not a vacuum leak issue. finally got the car to not die at idle with the ac on, it still idles a bit rough though. i'll take it back to the same tuner after i install my 92/90 setup since he doesn't charge for re-tunes (and i'm strapped for cash). if the tune doesn't fix it, i think i might open up the TB hole a little bit. thank you guys so much, this is a huge help.
06-22-2008, 12:16 PM
#16
Have pretty much the same issue over here. When I know I'm going to want to use the A/C I'll turn the idle up by adjusting my TB. Causes it to surge more but it stays on! Doesn't bother me cuz I only use the A/C once in a great while. My tuner is going to take another crack at it here soon.
06-22-2008, 09:03 PM
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If the AC is stuck blowing out the top vents, check the little vacuum hose that attaches to the intake by the MAP sensor. It provides the vacuum for the AC system to switch the vent output. If that hose is off, it will only blow out the top, except for any air that leaks by (which maybe why you feel some on the floor).
This could be the case, especially since you just got done doing the H/C swap. Only takes a few seconds to check.
This could be the case, especially since you just got done doing the H/C swap. Only takes a few seconds to check.
