OK this started to happen today, the car runs great without the a/c on. When i switch it to on the idle goes rom 1000 to 2500 and bounces up and down from 2500 to 2000 and doesnt stop. What could it be? vaccum line or boost leak or some sort?


thanks

 

idk...but mine does that too with the a/c on. heat too. it doesnt quite make it up to 2500, but itll go anywhere from 2k to almost bogging out and dying.

 

Check your ISC with a multimeter. Should be a consistent 32-36 ohms or so (varies with temp, as long as the numbers are all the same it is fine). Check pins 1&2 2&3 4&5 5&6. Some other misc things to check while you are in there is the slack on the cable, possible leaks at the throttle shaft, BISS oring (though not much of a worry), and confirm TPS settings. What are you idling at right now? If idle is too high it is remotely possible that kicking the AC on makes the car go from closed loop to open loop....but get all the basics out of the way first.

Did this happen before your tune?

 

well it all happen yesterday, getting tuned with the aquamist kit, kevin was tuning it and at 27psi we heard something pop, checked everything and everything seemed fine but the car was idling crazy like 3k then back down to 2500 just up and down finally, we go back to his place and do a boost leak test and the BOV(greddy type s) took a dump, put a jdm one on and started up fine go out tuning and it happens again, this is with the a/c off. me and kevin are puzzled, he says its the TB we do a boost leak again and it was the biggest TB leak he seen b4, but ok it was no problem he changed it out in a heart beat, start it up and it runs fine. I go home and the vaccum line popped off where i had my boost gauge hooked up, the car was running weird. I get home and fix it and start it up and the rpm jump to 3k and stays there for a while i call kevin and he said let it sit so i did and everything goes fine. Then today i changed out my mbc to a different one so i can run more boost and the idle seems to keep jumping a lil then stopping at 1k, i turn on the a/c and it goes up and stays there. I call kevin and he said drive it around for a bit to let it set it self, i do so. but with the a/c it idles normal then goes up to 2k-2500 then back down to 1k for a bit then goes up to 3k and goes back down. the car runs great with the a/c off but with it on its annoying...

thanks, and thanks kevin for putting up with my ?'s

 

Bet your ISC is all crispy and golden fried. Could have been a small backfire too, check for blown off hoses around mani.

 

Sorry for the noob question but what is an ISC?

 

Did u have retuned.. so go back fix by retuned...

 

ok my car did the exact same thing...I had installed a mini battery and left one of the ground wires loose. After i tighted the ground wire back up it went back to normal.