Electrical system problems when raining.
Prefader
Band Wagon
Looking for some help in determining where to start looking for the source of my problem here:
My 91 RT does some strange things when it's raining, or even just damp out (problem surfaced during the recent snowfall we had out here in MD). The first sign of trouble I notice is that the tachometer drops to zero whenever I'm below a certain RPM, which seems to vary. Usually it's when I let it drop below 1500, but at times I've seen it as high as 3000. Once the tach drops, I notice that lights are dimming, and sometimes I can hear the fan speed drop, too. On one occasion, I didn't notice a problem until I turned on my directional, and saw the tach bouncing in time with the blinker.
When this happens, I drain the battery pretty quick . . . if I turn the car off, I've got no juice to start it again, unless I keep the car running at higher RPMs for a while before shutting it off.
Unfortunately, I've only been able to check things out when it's dry outside . . . just the luck of the draw that I've only had time to work on it while it's dry. I see what I'd expect to see . . . ~12v from the battery with the motor off, jumps to ~14v with the motor on. I don't see voltage drop below 13v at any time once I start flipping on lights, heater, stereo, etc. This makes me think that the battery and alternator are just fine, but I'm not really sure. And why is this only happening when it's wet out?
Any tips on where to start my search are greatly appreciated. Thanks!
My 91 RT does some strange things when it's raining, or even just damp out (problem surfaced during the recent snowfall we had out here in MD). The first sign of trouble I notice is that the tachometer drops to zero whenever I'm below a certain RPM, which seems to vary. Usually it's when I let it drop below 1500, but at times I've seen it as high as 3000. Once the tach drops, I notice that lights are dimming, and sometimes I can hear the fan speed drop, too. On one occasion, I didn't notice a problem until I turned on my directional, and saw the tach bouncing in time with the blinker.
When this happens, I drain the battery pretty quick . . . if I turn the car off, I've got no juice to start it again, unless I keep the car running at higher RPMs for a while before shutting it off.
Unfortunately, I've only been able to check things out when it's dry outside . . . just the luck of the draw that I've only had time to work on it while it's dry. I see what I'd expect to see . . . ~12v from the battery with the motor off, jumps to ~14v with the motor on. I don't see voltage drop below 13v at any time once I start flipping on lights, heater, stereo, etc. This makes me think that the battery and alternator are just fine, but I'm not really sure. And why is this only happening when it's wet out?
Any tips on where to start my search are greatly appreciated. Thanks!
Comments
If it's only happening when it's wet... it maybe that the water is acting as a conductor for the electrical and shorting to ground. Whereas when it's dry this connection is not made.
use water while the engine is running
not a hose or something...
more like plant spray...
work your way through the bay...
and all...
at stages...
it somewhere there...
on the outside...
enginebay...
or blinker...
dunno
I like the idea of using a spray bottle . . . may try that later this week if a search of the hatch area isn't fruitful.
Thanks all!
P.S. What's up with the tach? Why is that being affected by this problem? I'm fairly sure that I don't understand how my tachometer works.
or...
ECU