Drifter

When I rev my engine to about 3000 rpm’s with the a/c and headlights on, all my lights including dash and interior, dims down at about 1000 rpm’s when the revs are returning to idle. It sometimes stalls the vehicle. I also suspect it to be the cause of my vehicle sometimes stalling when coming to a fast stop.

It doesn’t appear to do it with the a/c off.

Note: I lubricated the ISV (Idle stablelizer valve) and it seem fine.

tia

Dave
Las Vegas, Nevada
_________________________
87 Carrera / Blk & Grey (sold)
89 GT/ Black & Tam
03 Mini Cooper / Blk & Red
98 Montero / Seaweed Green & Tan

Drifter

I've concluded that the problem is related to the a/c compressor or the alternator or both.

I have a couple of questions:

Can the a/c compressor have a electrical draw on the alternator on deceleration to dim all my lights? Or can it be the alternator failing some how?

Any suggestions or solution is appreciated.

Tia

Dave
Las Vegas, Nevada
_________________________
87 Carrera / Blk & Grey (sold)
89 GT/ Black & Tam
03 Mini Cooper / Blk & Red
98 Montero / Seaweed Green & Tan

jyoon

someone's gonna tell ya to check all your grounds and wipe down all your fuse contacts

Drifter

Thanx jyoon,

I've done that but no improvements

Dave
Las Vegas, Nevada
_________________________
87 Carrera / Blk & Grey (sold)
89 GT/ Black & Tam
03 Mini Cooper / Blk & Red
98 Montero / Sea Green & Tan

SharkSkin

Probably alternator, battery, or wiring. Take a hard look at that battery, and have it load-tested. Same for the alternator if you can. When you turn on the AC you have the clutch, one cooling fan, and the HVAC fan all turn on at once. If you have one or more blown diodes in the alternator, it won't keep up at idle. The battery should have enough reserve capacity to keep it all working at idle, for a while.

What you describe is typical of a system with a weak battery. If the battery is too weak, the alternator has to work much too hard trying to charge it, and can blow diodes. This can also happen if the car is parked for long periods, and the battery is low when the car starts; maybe it's just enough to get the car going. Then the alternator charges like crazy, blowing diodes...

Replacing the alternator or battery alone may or may not fix the problem. Get them both checked; you can have them out in just a few minutes.

Drifter

Thanx Sharkskin for your input,

I will start with your suggestion as a starting point, hopefully its that simple.

Regards

Dave
Las Vegas, Nevada
_________________________
87 Carrera / Blk & Grey (sold)
89 GT/ Black & Tam
03 Mini Cooper / Blk & Red
98 Montero / Sea Green & Tan