4.9L engine stalls when ac engaged
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4.9L engine stalls when ac engaged
1995 F150 with 4.9L. Starts and runs fine, but stalls when ac mode engaged (also in defrost mode). Changed electrical connector at ac compressor clutch, disconnected wiring to ac clutch - no success. Autoparts stores shows an ac relay, but owner's manual and Haynes repair manual do not give any help on if the relay exists or it's location (under hood, under dash). It's getting hot in Texas, any help would be appreciated.
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The computer should be kicking up the idle speed like 100 rpm to compensate for the drag of the compressor on the engine. On carbed engines that was accomplished with an electrical olenoid just kickicg into the throttle lever, but with a computer I'm in the dark...sorry. Is your idle speed w/o air on a little low?
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If the ac works and no noise or high heat on the compressor, go back to idle control. As stated above, idle should be kicked up when ac/defrost goes on.
How is idle controlled on your vehicle? Any connections there? Anything traceable to the a/c unit?
How is idle controlled on your vehicle? Any connections there? Anything traceable to the a/c unit?
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Post Fiend
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From: Almost Heaven
1995 F150 with 4.9L. Starts and runs fine, but stalls when ac mode engaged (also in defrost mode). Changed electrical connector at ac compressor clutch, disconnected wiring to ac clutch - no success. Autoparts stores shows an ac relay, but owner's manual and Haynes repair manual do not give any help on if the relay exists or it's location (under hood, under dash). It's getting hot in Texas, any help would be appreciated.
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From: Texas
My 94 F-150 did the exact same thing back when it was under warranty thankfully, because it was a siezed up compressor. It would kill the engine when AC or Defrost was turned on. When driving down the road, I switched the AC on to check and the engine went into serious lug down mode and I immediately switched it back off.
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