rpm fluctuates with A/C

89tird

Registered User
at idle in drive or in park with the A/C on my rpm goes up and down every couple of seconds seems to be doing it everytime the A/C clutch engages, goes from like 750 to 650 rpm. also the vacuum moves in sync with the rpm gauge up and down.

??:confused:
 
at idle in drive or in park with the A/C on my rpm goes up and down every couple of seconds seems to be doing it everytime the A/C clutch engages, goes from like 750 to 650 rpm. also the vacuum moves in sync with the rpm gauge up and down.

??:confused:

If the charge in the A/C system is low, the compressor could cycle too frequently, and not for very long - 5 ~ 10 seconds or so. While recharging is a relatively simple process, keep in mind that if leaks are persistent, other issues could be part of the problem as well.
 
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so you think I could have low freon charge ? why would the vacuum gauge move too ?
 
The vacuum gauge moves because when the compressor clutches on, it creates load on the motor and for a second kind of bogs it down, then the computer compensates and raises the idle again. It does this every time I turn it on at idle in my 5 speed.
 
>so you think I could have low freon charge?

I would have it checked. There may be more than just the charge that needs attention.

>why would the vacuum gauge move too ?

Vacuum will naturally rise and fall as the engine changes speed based on influence from the compressor load (speed drops) and any counter activity from the computer (speed rises)...shouldn't be much tho.
 
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