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2G Rpm drop with AC on

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NFSPD_FL

Probationary Member
14
1
Feb 16, 2020
Melboune, Florida
I have read several threads about RPM drop and tried some of the suggested fixes but my issue remains. I would like to see if anyone out there had this issue and what the fix was.

My RPMS drop and almost stall the car when the AC is turned on and will return to normal if I turn AC off. Everything pointed to the Idle Air Control Valve. So I replaced it with a new Standard motor products one model AC146. But it still does the same exact thing. I have ECM link and my throttle position shows good.

Any help or suggestions will be appreciated.
 
Are you using the stock 4 wire connector factory alternator? The stock factory 2g has an alternator connector with 4 wires instead of some 2 wire aftermarket (or the 1g's 2 wires). One of the extra wires (green wire - "FR signal") is an internal alt load sense line signal to the ECU (pin 41) which controls idle speed (IAC) when extra load is present on the alt (like AC or high beams with blower and WOT). I don't know how/if ECMLink handles this. On my stock 99 the rpm actually increases when I turn on the AC due to this signal.
 
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Are you sure that your air conditioner compressor is in good shape and has plenty of refrigerant and oil in it? its hard for me to believe that any Dsm a/c system still has the factory fill in it without having any refrigerant added over the years, and when its added it waters down what oil is in the system to the point where if enough refrigerant is added there will be little to no oil left in the system, this will wreck your compressor over time, so you might have a compressor that is locking up.
 
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