Fj80 Pulsing voltage-alternator?

[poseidon]

Hello,

I did some searching and didn't find what i was looking for.

I recently bought a 92fj80. The PO said that he replaced the alternator with a non OEM due to $ constraints.

My concern is this. At idle the voltage reads 12-13 as I increase the rpms it rises. Then at about 1800-2k the needle hits that line just before the 18 and drops back down to 12 and then back up repeatedly. If I continue to increase the rpms the needle bounces faster.

Tonight it got worse and when the rpms are low and I have my blinker on (sitting in turn lane) the AT temp, alt, and brake light would blink on when my blinker did.

My first guess is that the alternator that went in there is a bad one. Any other ideas before I drop the $$$ for a new alternator.

Also what are the prices and options you all have experienced for a new or reman alt.

thanks
E

 

[GXO]

I had alternator needle jumps in my 1991 when I had lights on and used the turn signal.

Have you measured actual voltage at the battery/alternator?

 

[sseaman]

in my 91 this is not normal, you might try to hook up a meter and have someone rev the engine and see if the meter show the same output, it seems most dotn trust the factory gauges.

 

[poseidon]

the surging in the electrical is actually more than the gauge, you can see it in all the dash lights as well as actually hear it with the heater fan.

E

 

[TiredIronGRB]

Mine has done it ever since I got it, even with a different battery.

 

[dfmorse]

Poseidon;

U could take the "Princess" to a shop and have them check it out. It definitely looks like the voltage regulator or new brushes. Brushes u can do yourself; c-dan can sent u the parts or ur local toy dealer may have the parts. A re-man alternator is around $360.00, if memory serves.

...

 

[CJF]

Mine has done it ever since I got it, even with a different battery.

Repeated surging from 12-18 volts, as he states in his first post??

Curtis

 

[C6H12O6]

I'm having a similar issue and was just about to post up myself. My needle isn't bouncing around, and I haven't thrown a voltmeter on it yet, but in drive with the wipers going, lights on, stereo on, fan blowing, etc. the fan speed probably drops in half at idle at a light and goes up to speed with engine RPM. I'm also getting a weird phenomenon of various relays throughout the truck being VERY loud as they are switching on and off. Rear wiper, turn signals, front wipers, IPF lights... lots of weird noises, all electrically related, all at idle RPMs, all seem to improve when at cruising RPMs. I'm guessing regulator. Internal regulator? User serviceable?

I know, search and read the FSM.