Voltage on altenator (1 Viewer)

Dec 20, 2005
Was wondering if anybody knows what kind of voltage the alternator should be putting out under a load I have a 92 with the FE engine in it?

I'll describe my situation. I just changed out the alternator yesterday, because the old one was bad. Bought it from Toyota, and it cost me around $300 it was a rebuilt. The guage in the truck looked fine last night. Today in the cold, temp around 32 degrees F.I put a load on it meaning the lights, both the heaters, and the rear windshield defroster and noticed when I was driving the gauge was flicking up and down when at a stop light. It was flickering up and down in the good area of the gauge.

After noticing that I went and got my volt meter out.

These are the approximate readings across the battery.

No load-14 volts
Lights on -13.6 volts
Lights + main heater-12.5 volts
Lights + main heater + defroster-12.5 volts

Across the Altenator these are the readings.
No load-14.2 volts
Lights on-13.6
Lights + main heater-12.7 volts
Lights + main heater + defroster-12.7 volts

So does this mean that the altenator is still good? Or does it mean I am being a little to critical at this moment.
Nov 16, 2003
Dixie co. Florida
an alternator is RPM sensitive, it will not produce many amps at idle, 14.2 is good, repeat these tests but with the load on raise the RPM to 2k or so and see what you get.
Nov 16, 2004
Pasadena, CA
On the '97 first morning start (5 mins warm up) before go to work it shows 14.80 (No load) and going home at nite time speed 15-20mph Los Angeles traffic with all the accessories, lights on, etc... around 13.70.Will snap pic tonite after got home from work.
Aug 26, 2003
Cedar Park, Texas
...as per FSM
With the engine running from idle to 2000 rpm:
Standard voltage: 13.8 to 14.4 v at 77*F
Standard amps: 10 A or less

Sounds like your alternator is ok.
Jun 25, 2003
Rixeyville, VA
JerryLX450 said:
While we on the alternator subject.Do you guys recommends on those Hi out put alternator let say 200A?
I thought about going to one of those and its been talked about before. You can search around and find that they really dont put out more than the stock alternator.

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top Bottom