Charging issues...

[bigbadwolf078]

I have a 91 xl 4.0 that won't start but once jumped runs perfectly fine... I've changed the ground and the terminals with brass ones, I've had the alt tested and it hovers betweens 14 -14.2 , I've also changed the starter and the relay, I've also changed the battery three times from the junkyard .... I'm at a loss now so looking for advice

 

[malohnes]

If you've verified the alt and battery are indeed good, then I'd check the cables at the battery connection to start. And don't just check and clean the ends. Corrosion can migrate inside the cable and run the whole length of the cable and cause this problem. It happens mostly on the ground, but is ask common on the positive as well.

 

[natenkiki2004]

Corrosion can migrate inside the cable and run the whole length of the cable and cause this problem. It happens mostly on the ground, but is ask common on the positive as well.

^^ This.

 

[Number4]

Perform a voltage drop test.

https://www.explorerforum.com/forums/showthread.php?t=146784

 

[bigbadwolf078]

Just went ahead and replaced the positive cable also now, truck jumped off a lot easier but still not wanting to start back up when shut off... On my third battery but they were all junk yard battery's and the truck has sat for a few weeks without running... Hoping that maybe a brand new battery will solve this, going to have to wait a couple weeks thought because it ain't in the budget lol

 

[Rhett]

Are you sure it's an electrical issue? You have replaced a lot of stuff and the problem persists...makes me think something else, like FPR flooding or pump not priming or something like that.

 

[malohnes]

3 junkyard batteries is not really solving that part of the equation. If new battery doesn't solve the issue, the root cause is elsewhere. Given that the new cables helped, I'm inclined to think the battery will fix the issue.

 

[natenkiki2004]

You only replaced the positive cable? Do the negative, it's usually worse due to the way it attaches to the frame.

 

[2stroke]

I think he already did, at least he says he replaced the ground.

 

[Number4]

Not sure if he changed the neg. cable, the location or just the ends.

 

[Wolfie_85]

I'm with everyone who says "check out the cables again". Also, take it to a parts store and have them do a charging test. It can pinpoint things better than just a voltage reading. I had an alternator that seemed ok voltage wise, but it had a bad diode, and it "pulsated". Sure, it put out the right voltage, just not consistently enough to put a good charge on the battery.

 

[bigbadwolf078]

I've replaced both cables, not just the ends. I've had the alt tested and they said its good, 14-14.2 ... Its driving me crazy because once its jumped off its fine

 

[Wolfie_85]

Maybe you have a dead or dying cell in the battery. Advance Auto has used (tested) batteries. Wal Mart has decent deals too. Junkyard batteries are a bit of a gamble. I know you tried three, but sometimes, that's the luck.

 

[bigbadwolf078]

Could where the ground is mounted on the frame or motor make it so it wouldn't charge? If so what else could I ground the motor

 

[natenkiki2004]

The alternator uses it's case as a ground, maybe the bolts are all buggered up and rusted? Doubt it though. The alternator would charge through where the negative cable attaches to the block, right near the oil filter.

 

[larrydd999]

What is the battery voltage before you start after the vehicle sits overnight? It should be at least 12.5 or a bit more depending on how good the battery is. I'm assuming that in NC it isn't all that cold overnight yet.

 

[Number4]

What happens when you turn the key, without jumping it?

Jumping from another vehicle, would tell me:
A bad battery,
A starter drawing more amps than one battery can handle.

Typically, it indicates a bad battery.

 

[malohnes]

Resting voltage doesn't tell much. A dead battery can "look" good, voltage wise and not supply enough current to do anything like starting if there is sufficient sulphation or plate degradation or damage...read, old and abused.

 

[natenkiki2004]

Resting voltage doesn't tell much. A dead battery can "look" good, voltage wise and not supply enough current to do anything like starting if there is sufficient sulphation or plate degradation or damage...read, old and abused.

x2 on this. The battery that came in my parts Explorer showed a good voltage once I charged it up. Turning the key on, the fuel pump barely ran. Had the battery checked and it was tested to have 50 CCA. That's not a typo.

 

[bigbadwolf078]

Ended up being the battery, thanks guys... Now the stupid tag lights won't work, tried new lights but nothing.. Anyone know what the fuse is on that before I just replace the wire lol