gdavis67

I seem to be hunting a power ghost in my 92 pickup (4WD, 22re, 5 speed) that appears to be getting worse. I'm not sure all of these problems are related or not, but I'm not ignoring the possibility. First, several weeks ago the fuel pump circuit started acting up. Had never had a problem before but after having the truck parked for a couple of weeks while rebuilding the front end, the fuel pump circuit stopped working. If I jump out the fuel pump via the diagnostic port the pump works fine and truck runs great but without jumper - starts and runs 15 seconds then dies. Trying to sort that out using 4crawlers instructions. Then last week I took the truck in for an alignment. After leaving the shop, I noticed the brake and battery idiot lights on. Looking at the volt meter it was pegged at 18V. Shut truck off and restarted - lights still on volts around 16 but climbed and pegged after accelerating. The next day the battery was totally dead - no radio, no click at starter, nothing. After jump starting the truck I took it for some short trips. Shutting the truck off and restarting no problems ( oh, idiot lights still on). Next day, dead battery again. Jump started and drove truck again - this time, no lights and voltmeter steady around 14V - 16V, just like before problem started. Next morning - dead battery. I'm taking the battery and alternator today to be tested, but this seems to be a bigger problem than that. Has anyone had a similar problem and what did you find?

bugs1961

The brake and charge lights come on when the alternator isn't working properly. Everything you describe indicates a short in the alternator and/or bad diodes. The battery may have been damaged by overcharging voltage but it's probably going dead from a constant drain through the alternator due to a short. Been there done that.

Testing the alternator should answer your questions.

I highly recommend get a replacement at Toyota rather than an aftermarket one. I have quite a bit of experience replacing aftermarket starters and alternators over and over again after they fail in a couple of months. The Toyota unit is more expensive but the peace of mind is well worth it.

There are also threads here somewhere showing you how to rebuild your own alternator, which is the best alternative if you feel up to it. You'll save a lot of money and if you get OEM components (or OEM quality) it will last darn near forever. You can replace the brushes, diode pack, and bearings yourself.

gdavis67

Thanks bugs - exactly the opinion I was looking for. Will pull and have tested today! I fortunately have a good working spare off of a donor motor that is being built for next spring.