Fj40 losing power (1 Viewer)

[Tamoma77]

Hey everybody, I'm having an electrical issue with my 1977 fj40 Landcruiser, and I am completely lost on what to do and was looking for some guidance/ advice.
It seems to be the voltage regulator, but after testing two new ones and also the original one, it is still losing power.
After driving for a few miles, the vehicle starts bouncing and then the power dies in the middle of the drive. It won't start back up. Now, even with a fully charged battery, the car will start, for about a second or two, and then it loses all power. It's really weird, I checked all fuses and everything seems to be good, and it's a new bosch alternator, AutoZone tested it as bad, but I just had it tested by an alternator shop the other day as I asked for a quote to have the original rebuilt, and after testing it, they told me that it was charging at the correct voltage. I may swap the original back in, but it did die on me when I first got the truck, the wiring is old though, so maybe it is losing volts there? It's not the battery as I just put a brand new in.

Any thoughts?

~Tomoma77

 

[hobbes]

Check and clean your grounds. Battery to frame. Starter to frame. And perhaps the alternator to engine block.

See Coolerman’s comment in post 6 below. Yours is obviously not the same scenario, but it’s easy to eliminate it as a cause.

Fried wire from alternator

Alright, it’s been a while since I’ve asked anything of the collective ih8mud minds, but I’m trying to figure out why this bit of wire fried itself on my 40. It’s coming from the alternator and is a ground which is really strange. Anyone ever seen something similar and if so what was the...

forum.ih8mud.com

 

[jm599]

That’s what my pertronix did in its last day of life. We need more info maybe. What is voltage at coil. Spark at spark plug? Etc.
By “power” ... be more specific.

 

[ceylonfj40nut]

Fuel cut solenoid?

 

[fjc-man]

Mmmm.... worn out contacts in the electrical portion of the ignition switch?

 

[edwjmcgrath]

First, can you explain what you mean by doesn’t start or “loses power”. Does the starter turn the engine but the engine won’t run or does it not crank at all? I agree with many of these suggestions. Assuming you have a voltmeter, when it “loses power”, open the hood and check for voltage at the fuel cutoff solenoid on the carb. Then check for voltage on the coil. Then clean up all of your grounds (and battery positive) and cables. A really cheap and simple way to monitor the battery and charging system is to get a little voltmeter that plugs in your cigarette lighter. Google “voltmeter cigarette lighter”..