Keep blowing “engine” Fuse, and I'm out of ideas. Please help. (76 FJ40 - US)

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My guess is that your alternator isn't charging. That might be a voltage regulator problem, but, it sounds like you now have it hooked it up properly. I wonder if your battery was ever over-charged, or if the rectifiers in the alternator were damaged? Do you have a Hayne's manual?
I do have a Haynes, it's been super helpful. This is not the original alternator but the battery is brand new and the voltage regulator is brand new(ly remanufactured)
 
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Ok, so I went to check the battery voltage (12.4 btw) and either the new F wire came loose, or I forgot to plug it into the alternator (unlikely but possible.) I plugged it in, cranked and the ammeter is reading 👍🏼 I'm going to keep an eye on that wire and make sure it's not rattling off the connector. My 40 is definitely a shaky drive, so it's entirely possible.
Thanks for the help everyone!! You're the best!
IMG_3742.JPG
 
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Well, I thought everything was fixed, but yesterday I drove it somewhere and came back to leave and the ignition system was doing the same thing. I was able to pop the clutch and get it started to drive home, but now I'm back to square one :/
 
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Mine does that. It is telling you that you have energized the ignition and that you are using power. You have an OEM ignition switch to replace it with in the mail?
 
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Good grief.. I'm so confused. So, right after I replied, I went out, double checked that the new OEM switch was plugged in all the way.. and it cranked right up. At first I thought, "maybe it wasn't seated fully in the female part of the plug", but then the ammeter wouldn't have reacted to the key turn, right??
I have no idea what's happening. The inconsistency is going to make me really second guess taking it out anywhere.
 
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what is the condition of your fuse block and the back of the fuse block ? what do the wire connections at starter look like ?
 
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what is the condition of your fuse block and the back of the fuse block ? what do the wire connections at starter look like ?
The starter is brand new, as well as the main wire, going from it to the battery. I took off the fuse block and looked at it last week, everything looks intact, just old. All of the wiring going to it seem to be in decent shape, given its age.
 
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I have found that taking each fuse out and cleaning terminals/tabs finds issues that looked fine. The symptoms seem like the ignition switch may not be contacting the starter terminal properly ,
 
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How far does the ammeter dive when the key is in the "on" position? Don't leave it there for long, it can heat up your coil too much (not true with electronic ignition iirc). But before you trigger the starter, there is a dip from the brake lamps going on (I'm in neutral and on a slope) and the dip from the ignition coil being energized.
 
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JohnnyC

Long ago TLCA# 2231
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When ever I have my amp meter go down to negative out of the blue it has always been a problem with the white w/blue tracer off the alternator… start tracking back and see if it is corroded/failing at any point on that wire…. Mine was a bad connector on the white/blue wire and upon removing the wire wrap it came off the connector … corroded and most likely holding on from a few strands

Had it happen again 15 years later (DD)

Also even though the fuse block looks good one of the wire connectors could be loose or oxidized …

Take the fuse block and clean it … sand paper … I use a lil dielectric and prettier it up
 

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