Engine stalling/dipping when fan kicks in.

[jfdid]

Guys, having a pretty annoying problem. Car idles at normal RPM(750-800) and when the rad fan kicks in, the engine RPM drops WAY down, to like 500, and stalls about half the time. Any idea? The alternator only has 20,000K on it.

Short? Fan's garbage or what?

Thanks guys.

 

[missouri_dsm]

check for loose connections on your alternator and your battery. Also check for bad or loose ground wires, you have them all over the engine bay and they are very important.

 

[luv2rallye]

Try unplugging the fan and see if the problem is still there. If so, you have a short or significant current draw in the wiring/relay somewhere. If not, the fan or alt. is suspect. Measure voltage at battery (car running) before and after fan kicks in. Also measure voltage across the fan itself.

 

[jfdid]

According to MMCD, the voltage drops down over a Volt when that fan kicks in, is this normal? Even though the fan isn't a static device, is it possible to get an accurate Resistance reading across it? It's been a couple years since my electronic courses.....

Unplugging the fan works, obviously, because the problem only occurs when the fan kicks in.

 

[heppm01]

Your ISC should compensate for the draw by keeping your idle at 750. If it is dropping that tells you your ISC isn't doing its job.

M