2007-12-20 04:14:47 · 3 answers · asked by papanma 1 in Cars & Transportation ➔ Car Makes ➔ Other - Car Makes
I own a shop, and what I would do is this; With the engine off, have a buddy watch the AC compressor while you turn the heater on. Does it click at the front of the compressor? If so, then its activating the AC unit, and when the AC is activated it raises the idle speed to compensate for the drag on the engine the AC creates. If not; then you need to go over each & every vacuum hose on the engine for a leak. Also; listen to see if you can detect any hissing noise under the dash or in an around the engine compartment. Any vacuum leak will cause the engine rpm's to rise. I suspect you may have a vacuum hose or cannister leaking when you activate the heater.
Glad to help out, Good Luck!!!
2007-12-20 07:27:40 · answer #1 · answered by Anonymous · 0⤊ 0⤋
The first thought that ran through my head is when you put on heat, it may be switching on the A/C system as well. The operating computer raises the engine RPM if it thinks that the A/C is on to offset the power loss the A/C pump causes.
2007-12-20 05:07:28 · answer #2 · answered by Robert M 7 · 0⤊ 0⤋
Are you sure it's only then, or is it that it's already warmed up and you have the heat on anyway, many cars don't rev up until they reach optimal operating temperature, especially during the winter
2007-12-20 04:23:14 · answer #3 · answered by Anonymous · 0⤊ 0⤋