Ac make engine run different
Thread Starter
Heel & Toe
Joined: Jul 2017
Posts: 23
Likes: 0
Ac make engine run different
When I turn on a/c when driving I can feel the engine run differently.When I give it gas it goes away.Anyone know what causes this?
Last edited by Bigdade; Jul 22, 2017 at 10:51 PM.
Le Mans Master
Joined: Jul 2000
Posts: 6,664
Likes: 162
From: columbia city in
lol you give us so much to work with.I assume that when you turn on the a/c that it puts a load on the motor.the rpm goes down .This is normal.your idle is controlled by the computer[If this is a crossfire}.If it is running very rough , I would check the tuneup.plugs, cap, wires,
Last edited by terry82; Jul 22, 2017 at 11:37 PM.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Many GM cars in the 70's (and some early C3's) had devices that increased throttle a bit when the A/C is activated. Research your model year to determine if you are missing any such hardware on your carb/engine.
If you have a later model C3 with ECM module, check for any trouble codes being recorded and, if needed, take it to a qualified and reputable mechanic. Sometimes, a very simple fix can resolve a problem and prevent longer term engine damage.
If you have a later model C3 with ECM module, check for any trouble codes being recorded and, if needed, take it to a qualified and reputable mechanic. Sometimes, a very simple fix can resolve a problem and prevent longer term engine damage.
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
something like this.....what doesnt Walmart sell
https://www.walmart.com/ip/ACDelco-I...&wl13=&veh=sem
thinking of sticking one on so when my temp gets to 190 the idle doesnt want to go to hell due to this garbage they call gas.
2026 Loser of the Year
Joined: Sep 2013
Posts: 36,597
Likes: 7,046
From: New Or-leens Loo-z-anna
It's amazing how we can feel a 15-20 h.p. "drop" (as when the a/c engages), but we can add something to increase h.p. by 15-20, but we do not notice the improvement.
Thread Starter
Heel & Toe
Joined: Jul 2017
Posts: 23
Likes: 0
Many GM cars in the 70's (and some early C3's) had devices that increased throttle a bit when the A/C is activated. Research your model year to determine if you are missing any such hardware on your carb/engine.
If you have a later model C3 with ECM module, check for any trouble codes being recorded and, if needed, take it to a qualified and reputable mechanic. Sometimes, a very simple fix can resolve a problem and prevent longer term engine damage.
If you have a later model C3 with ECM module, check for any trouble codes being recorded and, if needed, take it to a qualified and reputable mechanic. Sometimes, a very simple fix can resolve a problem and prevent longer term engine damage.
Thread Starter
Heel & Toe
Joined: Jul 2017
Posts: 23
Likes: 0
Melting Slicks
Joined: Sep 2009
Posts: 2,414
Likes: 214
From: Sarasota Florida
I have been driving for 52 years. I would say you are probably experiencing the normal load the AC puts on the motor. In the 60s and 70s, we would shut off the air when we wanted better performance for spirited driving. My 71 kicks the idle up when I turn on the AC. Depending on the year of your C3, you should expect the same.
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