I have a weird issue with my A/C: it goes off and on VERY rapidly...so fast that you wouldn't even know it's happening...except for the fact that we had a laptop hooked up to the AEM EMS and watched it as it was happening! You can also feel the car "hiccuping" as you drive. It just feels sluggish with the A/C on.

We checked all the A/C settings in the AEM, and my tuner says it's not an AEM issue. He thinks it may be a bad fuse?

Any thoughts or suggestions are welcome. Thx.

 

Usually on/off at a fast rate means the switch is hovering at it's pressure cutoff.

In other words, low freon.

 

Or low idle speed, or it's been overcharged or the high side pressure is hovering at cutoff pressure.

In OEM configuration the PCM powers the Compressor clutch relay when system pressure is high enough and AC request is present from the control panel.

Since you aren't dealing with an OEM PCM it complicates things.

1st make sure both cooling fans are running with the AC on. Inoperative fans crank the high side pressure. I've seen other EMS cars that didn't turn on the fans with AC request.

 

Thx guys.

Both fans are running.

Who can I take the car to so they can check the pressure & freon? A general mechanic? Or does it have to be somebody that specializes in A/C issues?

 

I know 1 guy in Alabama, and 1 guy in Long Island (Lawnguyland) That cat fix it, but it's a bit of a drive for ya man.

 

Well, South Florida's real nice this time of year...and there's some "hot" sights at the beach that will make the trip down all the more worthwhile.

 

I would verify (with a voltmeter) that the signal to the compressor clutch is not dropping out. Very helpful to see the signal from the ECM, and wether the compressor is being told to shut off.