A/c engine idle
Thread Starter
5th Gear
Joined: May 2006
Posts: 5
Likes: 0
A/c engine idle
'95 Vette auto trans "P" eng.
Electronic auto air system
AC works fine (adequately cold), even with outside air temp of 100+
However, with air on, Engine idle remains high, when you remove foot from gas pedal. I know engine will idle higher when air is on but if I am doing 35 mph, the car will stay at 35 until I step on the brake. Then I have to continually put pressure on the brake to keep slowing the car down. Certainly will not do brakes any good.
With air off car slows down properly.
Electronic auto air system
AC works fine (adequately cold), even with outside air temp of 100+
However, with air on, Engine idle remains high, when you remove foot from gas pedal. I know engine will idle higher when air is on but if I am doing 35 mph, the car will stay at 35 until I step on the brake. Then I have to continually put pressure on the brake to keep slowing the car down. Certainly will not do brakes any good.
With air off car slows down properly.
Burning Brakes
Joined: Feb 2009
Posts: 785
Likes: 3
From: Richmond Virginia
What is the idle speed after engine is hot w/out AC on ? What is the idle speed with AC on? If nothing is sticking/binding as far as throttle blade or cables.....possible dirty/sticking or bad IAC valve.
Drifting
Joined: Sep 2003
Posts: 1,363
Likes: 7
From: 1994 LT1 Coupe 6-speed with FX3 & 2000 LS1 Vert 6-Speed with F45 Hunterdon County, NJ
it sounds like a sticking IAC (idle air control)..however, when AC is on, engine bay temps are likey hotter too, so it could also be a sticky TB or cable which only acts up when really hot...
If the throttle-body coolant hose bypass has been done, it might actually make the TB hotter and cause sticking which wouldn't occur at cooler temps...
Last edited by theadmiral94; Aug 1, 2009 at 10:01 AM.
