metalry101
R/C addict
- Location
- Sandy, UT
First off, this is on an '88 XJ with the 4.0 and 226K on the odometer.
My problem is that it won't hold constant voltage. I splashed through a couple very small puddles (to tell you how small, I was in 2WD) out in the desert a couple weeks ago and since then my charging system has confused the hell out of me. It stopped charging completely on the way home on that trip and I had to get my dad to bring a spare battery to get me home. After that I just charged the battery every night and drove around on battery power. About 4 or 5 days later while driving and on the throttle pretty hard (4,000 RPM or so) I noticed my headlights got brighter all of a sudden and the gauge went back up to 13 or 14 volts. Since then it's been moody. Sometimes I start it and it goes right to 14 and stays there just fine. Sometimes I start it up and have to rev it up to 4500 RPMs to get it to get the voltage up to 14 rather than 10 or 11, sometimes it'll start at 14 and then as I'm driving drop down to 10 or 11 (it seems to drop fairly quickly, I don't stare at the gauge...but it happens quickly), and almost always, if I rev up to 4000+ RPMs for a couple seconds, the voltage gauge goes back up and the headlights return to normal. Today when I drove to work it seemed to work fine the entire time. Ditto for the drive home. When I drove to school a little later, it never got above 10 or 11 volts, no matter how much I revved the engine. Ditto for the drive home. Tonight in the driveway after being home for a couple hours, I again started it and it was at 10 or 11 volts. I built it up to about 4500 RPMs and now I'm getting proper voltage again. I should clarify that I don't have to maintain 4000+ RPMs to get it to hold voltage. After it goes up to 14 or so volts, it'll hold it for a while, even at idle.
I'm thinking it's the alternator since that's the only thing I know of in the charging system that would be affected by RPM's. My dad says it could also possibly be the relay or whatever it is that the lead coming straight off the alternator goes to. I can't think of anything else that it could be. Any ideas or suggestions?
My problem is that it won't hold constant voltage. I splashed through a couple very small puddles (to tell you how small, I was in 2WD) out in the desert a couple weeks ago and since then my charging system has confused the hell out of me. It stopped charging completely on the way home on that trip and I had to get my dad to bring a spare battery to get me home. After that I just charged the battery every night and drove around on battery power. About 4 or 5 days later while driving and on the throttle pretty hard (4,000 RPM or so) I noticed my headlights got brighter all of a sudden and the gauge went back up to 13 or 14 volts. Since then it's been moody. Sometimes I start it and it goes right to 14 and stays there just fine. Sometimes I start it up and have to rev it up to 4500 RPMs to get it to get the voltage up to 14 rather than 10 or 11, sometimes it'll start at 14 and then as I'm driving drop down to 10 or 11 (it seems to drop fairly quickly, I don't stare at the gauge...but it happens quickly), and almost always, if I rev up to 4000+ RPMs for a couple seconds, the voltage gauge goes back up and the headlights return to normal. Today when I drove to work it seemed to work fine the entire time. Ditto for the drive home. When I drove to school a little later, it never got above 10 or 11 volts, no matter how much I revved the engine. Ditto for the drive home. Tonight in the driveway after being home for a couple hours, I again started it and it was at 10 or 11 volts. I built it up to about 4500 RPMs and now I'm getting proper voltage again. I should clarify that I don't have to maintain 4000+ RPMs to get it to hold voltage. After it goes up to 14 or so volts, it'll hold it for a while, even at idle.
I'm thinking it's the alternator since that's the only thing I know of in the charging system that would be affected by RPM's. My dad says it could also possibly be the relay or whatever it is that the lead coming straight off the alternator goes to. I can't think of anything else that it could be. Any ideas or suggestions?
