Just did my 4.0 swap and thought the alt was bad so I took it in to get it tested and it's good, I have new battery connections and cleaned the connections to the alt, any ideas where to look next?
Alt question
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This isn't meant to insult, but you didn't mention if the battery itself was any good. Have you checked that? Batteries can die pretty fast.
Also, what are you symptoms? Not charging? Not starting? etc?
Also, what are you symptoms? Not charging? Not starting? etc?
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Does your alt light in the dash work? If it doesnt, the alt wont work.
Are you getting power to the field wire on the alt? If not, the alt wont work.
Do you have battery voltage at the output wire on the alt? If you dont, then the wiring is screwed up.
Are you getting power to the field wire on the alt? If not, the alt wont work.
Do you have battery voltage at the output wire on the alt? If you dont, then the wiring is screwed up.
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I would suspect a wiring issue.. get a wiring diagram and follow the wiring and check for voltage at each point.. find out where the charging volts stop.
The battery is good the alt checked out good at autozone, and yes the battery light is on, and the gauge is working also, as far as symptoms , it's not charging,
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Some of the testers they use aren't great. They don't all do a proper load test and if it sees 12V it passes.
Hook a volt meter up to the battery. Note voltage. Start engine, did voltage go up or down.
Rev engine smoothly up to 3000 RPM, does voltage go up, down, or hold steady?
The answers to those questions will give me a pretty good idea of where exactly the problem is.
Hook a volt meter up to the battery. Note voltage. Start engine, did voltage go up or down.
Rev engine smoothly up to 3000 RPM, does voltage go up, down, or hold steady?
The answers to those questions will give me a pretty good idea of where exactly the problem is.
This!
Some of the testers they use aren't great. They don't all do a proper load test and if it sees 12V it passes.
Hook a volt meter up to the battery. Note voltage. Start engine, did voltage go up or down.
Rev engine smoothly up to 3000 RPM, does voltage go up, down, or hold steady?
The answers to those questions will give me a pretty good idea of where exactly the problem is.
The voltage doesn't move other than going down after starting
Hook a volt meter up to the battery. Note voltage. Start engine, did voltage go up or down.
Rev engine smoothly up to 3000 RPM, does voltage go up, down, or hold steady?
The answers to those questions will give me a pretty good idea of where exactly the problem is.
The voltage doesn't move other than going down after starting
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It drops from about 12.25 or 12.5 to 11.5 when you start it and then holds steady as the engine revs up?
If that is the case, the wiring is ok, the alternator is shot and only producing about 12 to 12.5 volts unloaded. The 11.5 you read is all that is left.
If that is the case, the wiring is ok, the alternator is shot and only producing about 12 to 12.5 volts unloaded. The 11.5 you read is all that is left.
Yah I kind of figured that, I started it up and disconnected the battery and it died instantly
Explain "disconnected". It should run still with the positive pulled, but should die with the negative. Pulling the positive will run the alternator at max output, so it's not the nicest thing to do to your alternator.
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Where did you hear that? I started my truck, pulled the battery out, put it in my other truck, started that one, pulled the battery back out, and put it back in the 1st truck! (All because I didnt want to have to reset the all the BS in the radio on the 1st truck.
)
Where did you hear that? I started my truck, pulled the battery out, put it in my other truck, started that one, pulled the battery back out, and put it back in the 1st truck! (All because I didnt want to have to reset the all the BS in the radio on the 1st truck.
How can it run without a ground?
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I looked in the power distribution box and there is a 60 amp fuse for the alt, but there's no fuse? It doesn't even have both connectors for the fuse to slide in, is this my problem?
Adsm08 I tried your suggestion again about noting voltage, it slowly drops the longer I let it idle to the point it quits running, there are two places for fuses for the alt in the power distribution box, 1 and 2, there was no fuse in the one marked 1, I'm not very good at reading these diagrams but I think on the 4.0 they only use one? Can some one look at there's and tell me how there's is? Thanks
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