Topic: Blown 80amp on fuse box

[Jaysen]

Hey guy I went through 2 80 amp fuse it's the alternator fuse!Keep on blowing up on me and have no idea why! happen when you drive and turn or gas hard, everything like the gauges die but the engine stay running but once you shut it off you can't start it back up! I'm thinking maybe cause of my harmness has some opening somewhere? Need help guys!!!

[Sparkplug]

Check o2 sensor


seen this a bunch of times, was o2 sensor wire shorting out, and popping the fuse, check the wire all the way down the harness

[Jaysen [OP]]

Thanks I'll check it out!

[superyota]

get a volt meter and check to see how much your alternators putting out when you raise the rpm's.  i bet you have a bad alternator(regulator built into alternator) that spikes at high rpms.

[yotarunner85]

A volt meter won't help if your checking the alternator voltage. Voltage has nothing to do with a fuse blowing, to many amps are what causes a fuse to blow. So what you would need to check alt output is an amp meter that's rated over 80 amps. The only problem is the factory alt(for older year trucks) is only rated at 40 amps and I highly doubt that it would spike over 80 amps. Most of the time a fuse blows is from something shorted to ground. Check the wirring from the fuse and follow the wire to see if rubbing, pinched or any bare wire that could be grounding out. If all the wirring is ok, check the componets that the wire goes to, unplug one at a time untill the fuse stops blowing, then you will know what is causing the fuse to blow. If this doesn't help let me know some more info, like year, model, and engine and I will see if I have a wirring diagram.

[pumkin toy]

i had this exact same problem on my 84 pickup. it had an externally regulated alternator.  i never pinpointed the exact issue. I just ended up swapping the alternator and alternator harness to the newer internally regulated setup. I never had a problem after that.  external regulators are a pain anyways

[Jaysen [OP]]

Thanks guy I found the problem. I had a open wire on a O2sensor! thanks

[Sparkplug]

Thanks guy I found the problem. I had a open wire on a O2sensor! thanks

Do I get a Cookie???

[yoshaleng]

 



not just a cookie, the whole bag!

[yotarunner85]

An open wire won't cause a fuse to blow. I assume you mean a shorted wire.