I replaced my voltage regulator about 3 years back and it's already misbehaving. Same symptom, my voltage will sudden jump up to about 18V. It seems abnormal. Maybe my aftermarket regulator was garbage? What's the best available? (All stock, no winch or fancy add ons.) What is the preferred source for voltage regulators? Should I be looking for a deeper culprit?
Voltage Regulator source for 3FE
- Thread starter FJ80Duo
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Is your alternator an OEM unit? The voltage regulator is internal to the alternator on a 91 with an 80 amp unit. It is soldered to the rectifier board.
If it's overvoltage then the regulator is toast regardless of who makes the alternator.
Unfortunately there aren't many good quality sources for alternators out there. OEM rebuilds are the way to go on a 3FE. Direct bolt in and will last a good long time.
Unfortunately there aren't many good quality sources for alternators out there. OEM rebuilds are the way to go on a 3FE. Direct bolt in and will last a good long time.
Does yours have an external fan? If so then it is probably the 80A unit, which is not re-buildable. You can swap it for the 90A unit, which can be rebuilt, but will need a little modification to the alt. housing.
Also agree OEM is the way to go.
Also agree OEM is the way to go.
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Has the integral fan. Regulator should be replaceable, but requires soldering.
Not important though, I want a Denso in there. So I'll replace the whole thing.
Anybody got a spare laying around for a 3FE??? If so, please PM!
Not important though, I want a Denso in there. So I'll replace the whole thing.
Anybody got a spare laying around for a 3FE??? If so, please PM!
Hello there,
my 91 80 is having EFI issues. I have already searched and found some answers on this forum. I moved the relay inside and installed a 12v fan to keep it even cooler. The fan is from an old xbox so i dont think that there is too much amp draw. i also upgraded the wires to 10 gauge.
My question is whether the alternator could be causing surges as the fusible link fried and the 15amp fuse for the EFI also fried. I tested the alternator output before i moved the relay and it jumped form 14.5 to 18+. I didn't think much about the fluctuation but now, since the cruiser is dead until a get a new fusible link, it made me rethink what could have transpired to cause the relay to get hot and the fusible link to fry.
Any ideas will be greatly appreciated.
Couple of questions:
How old is the alternator and is it an OEM unit?
Which of the 3 fusible links failed?
When you noticed the voltage spike on the alternator, how were you testing it and under what conditions?
If your EFI fuse popped, it wouldn't have been from over voltage, but rather a short somewhere in the system. I would try to isolate this problem first or the engine will not start.
Thank you for your reply.
The alternator is about 5 years old, not OEM.
The blue fusible link failed, the one with bigger diameter connector ring. The block also appears melted.
I tested at the battery with a/c off, engine was hot.
The alternator is about 5 years old, not OEM.
The blue fusible link failed, the one with bigger diameter connector ring. The block also appears melted.
I tested at the battery with a/c off, engine was hot.
That is a 100 amp fusible link.
I would first check from the junction box FL MAIN load side (engine harness side) to ground and make certain there is no direct short in the harness or alternator.
If that checks out, I would then replace the fusible links WITHOUT replacing the 15 amp EFI fuse, and put a meter from the load side of the EFI relay (pin 4) and look for a short to ground.
If that checks out I would look for a short to ground directly off the EFI fuse.
Somewhere in your system something is shorting out. It is very possible that your alternator is done. Aftermarket alternators and starters have a very short lifespan n these vehicles.
Thank you Jonheld. I should be getting the new fusible link tomorrow. I will follow you testing process.
Could there be something going on with the pump itself?
Could there be something going on with the pump itself?
I assume you mean the fuel pump.
There "could" be any number of issues as the EFI fuse feeds a host of sensors as well as the fuel pump. It could be a shorted O2 sensor wire. We can speculate all day, or you can use a meter and diagnose the issue.
Well, i went through the testing procedure you described, and also followed the "efi woes" procedure.
*NO CEL
*AT light is on
*Charge light is on
*Installed new fusible links
*No reading at the #4 pin on the relay
*12+ at the EFI fuse
*12+ at brass screw
*No reading at the B+ connector
I know i probably have a short somewhere but my electrical knowledge is very basic. I don't want to take it to a shop yet.
Thank you for any other ideas and your input so far.
*NO CEL
*AT light is on
*Charge light is on
*Installed new fusible links
*No reading at the #4 pin on the relay
*12+ at the EFI fuse
*12+ at brass screw
*No reading at the B+ connector
I know i probably have a short somewhere but my electrical knowledge is very basic. I don't want to take it to a shop yet.
Thank you for any other ideas and your input so far.