when I turn on my A/C my RPMs go up by 600 and start hopping. what would cause this? It only hops with the A/C on and stops when i turn it off. also when i turn my lights on it whines if i cut them off it stops.

 

it almost sounds like you have a bad ground. i had a problem like that when i turn my lights on my windsield wipers came on. i would check that first. but i am not an expert hopefully i helped

 

where do i look for a ground and also the seprate issue why would rpms go crazy with a/c on

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by allshownogo &raquo;</TD></TR><TR><TD CLASS="quote">where do i look for a ground and also the seprate issue why would rpms go crazy with a/c on</TD></TR></TABLE>

A/C is belt driven, it puts more load on the engine, the engine compensates.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by allshownogo &raquo;</TD></TR><TR><TD CLASS="quote">when I turn on my A/C my RPMs go up by 600 and start hopping. what would cause this? It only hops with the A/C on and stops when i turn it off. also when i turn my lights on it whines if i cut them off it stops. </TD></TR></TABLE>

It's normal for the ECU to increase engine rpm with increased load, for example when the A/C is ON. The hopping rpm and whining, however, is abnormal. Check whether the alternator belt is loose and slipping. If the belt is fine, the alternator might be bad.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by saywhat &raquo;</TD></TR><TR><TD CLASS="quote">

A/C is belt driven, it puts more load on the engine, the engine compensates.</TD></TR></TABLE>



It can be worse if you have underdrive pullies.

 

no underdrive pulleys its a stock d15b7 i just need it to last until i cant buy my swap but anyway a bad alternator could cause a bad idle with the a/c on? ive already cleaned IACV,FITV, just put on a used T/B with TPS and MAP sensors. newT/B gasket. i fixed previous powerloss prob but now this.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by allshownogo &raquo;</TD></TR><TR><TD CLASS="quote">...but anyway a bad alternator could cause a bad idle with the a/c on? </TD></TR></TABLE>

Yes. Take your car to AutoZone where they will test your battery and alternator free of charge. But first check whether the belt is loose, glazed, or slipping.

 

Hey thanks man thats was a different answer i was looking for.

 

would that also affect my idle being high for a few seconds when i come to a stop(alternator)

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by allshownogo &raquo;</TD></TR><TR><TD CLASS="quote">would that also affect my idle being high for a few seconds when i come to a stop(alternator)</TD></TR></TABLE>

Possibly. Increased electrical load (e.g., A/C or headlights) will increase engine rpm, which could fluctuate up and down if the alternator intermittently failed to supply adequate charge.

 

well if i have nothing on and im coming to a stop my car will stay at 100RPMs for about 4 seconds before droping down to normal. this is with nothing on not even radio

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by allshownogo &raquo;</TD></TR><TR><TD CLASS="quote">well if i have nothing on and im coming to a stop my car will stay at 100RPMs for about 4 seconds before droping down to normal. this is with nothing on not even radio</TD></TR></TABLE>

This problem probably has a separate cause from the potential alternator problem mentioned earlier.

 

my last post was incorrect.my car will stay at 100 RPMs and then go to normal not 100RPMs sorry.

 

i think my keyboard is messed up. its not 100rpms its 1000 my keyboard sucks sorry again

 

bump an ideas