Engine idle with/without AC - Third Generation F-Body Message Boards

allaneyre · 09-06-2009, 01:56 PM

Hi,

I think I've been having issues with my 91 Z28 TPI camaro. Previously, whenever the AC compressor engaged, the idle was dropping... far enough that the engine seemed to almost get bogged down enough to stall out.

Yesterday I took out and cleaned up the IACV with some carb cleaner, the IACV housing (as best I could without removing it) along with the butterflies on the throttle body (someone suggested that previously). Then I put everything back in along with a new gasket (the old one snapped on removal) on the IACV. I also checked for vacuum leaks by spraying the carb cleaner around the fittings and tubes but didn't notice any change in the engine sound while I did it.

Afterward, the idle was rock solid without any accessories on at about 700-750 (The Chilton man. says it should be 400-450???), but again... with the AC on, it would dip slightly and then shoot up to about 1000-1100. The compressor is only staying on for about 2-3 seconds and then disengaging again so I'm not able to see if it would level out. As soon as the compressor goes off it falls back to the 700-750 range again. It does not seem to dip far enough anymore to seem like it might stall following the work I did.

My question is... is this normal idle behavior with the AC running or should I be trying other things like replacing the TPS/PCV and/or having someone give it a more thorough tune-up?

Thanks!!!

allaneyre · 09-08-2009, 12:19 PM

anyone?

fleetmgr · 09-09-2009, 01:13 PM

You have a couple of problems. I'd call the Chiltons a misprint..but not sure. That seems pretty slow.

The behavior when you hear the A/C compressor cycle off isn't normal, nor is the compressor cycling like that. Can't help with idle problems, but it sounds like your A/C may need a recharge.