Intermittent charging even after new parts.

[Running an Explorer]

I've got a 1998 explorer 5.0 awd with charging issues. It all started when I cranked it one day and it started slow. So I replaced the battery and haven't had that problem since. But now watching the voltage guage the needle will showing low voltage and after driving for a minute my coolant guage will go all the way to hot then fall back and only do that once. The oil pressure guage will show high all the time. And then sometimes I'll drive it and everything will be showing normal. When the guages are acting up I'll check voltage at the battery with it running it'll only be showing 12.2v (this is what im assuming drained the old battery) then when the guages are normal it'll be showing 14.1v or 14.2v. (Most of the time it'll not the charging right) I've checked the voltage on the bolted on wire and it reads the same as the battery. I've also checked the connector on the alternator with 2 wires and it shows voltage there too.
So I bought a new alternator and it was acting up the same as before. So I returned it and had my old alternator tested (off the vehicle) and it showed good, so that's what I've got on it currently. I've read on here that the starter solenoid can be a possibility too, so I replaced the starter and solenoid and it is still messing up. So with a new battery, alternator and starter solenoid the problem still persists. It does seem to charge correctly when for about 10 min when first driving it in the morning. To my knowledge there is no draw on the battery will sitting. I've let it sit for a week with this problem and it will still crank ok.
So I'm at a loss of what the problem could be, the only 2 things that come to mind are battery cables or a bad ground. Where are good places to check bad ground wire?
Any other ideas and imput will be great appreciated. Thank you in advance.

 

[C420sailor]

I agree with your assessment. Very poor grounds will cause issues with voltage and cause instruments that measure via resistance to be out to lunch.

Take a good look at your battery cables. Many will corrode internally. Beyond that, this is going to be a game of both visual inspection and using a DVM to check resistance throughout the ground side of the system.

If you’re a smart cookie and have access to schematics, you can likely figure out which grounds are suspect based on where your symptoms are located.

 

[Running an Explorer]

I agree with your assessment. Very poor grounds will cause issues with voltage and cause instruments that measure via resistance to be out to lunch.

Take a good look at your battery cables. Many will corrode internally. Beyond that, this is going to be a game of both visual inspection and using a DVM to check resistance throughout the ground side of the system.

If you’re a smart cookie and have access to schematics, you can likely figure out which grounds are suspect based on where your symptoms are located.

Thanks for the reply, I will update as soon as I figure something out.
Additionally, I've read where the battery bulb in the dash could be a reason to not "excite" the alternator. But the light is working properly. It comes on when I turn the key to run and then it goes off when I start the vehicle.

 

[Running an Explorer]

Well thankfully I found what the problem was with the help of this forum. It looks as if the previous owner had a repair done and the ground wire was never reconnected.

 

[donalds]

Nice and easy fix

 

[410Fortune]

Yeah that ground is just kinda important lol
There are only 3 connections from the - side if the battery one to the frame one to the body and one to the engine

The frame and engine ground are sometimes the same wire

Without the big ground hooked up everything on your truck is trying to find a ground through the one small
Lead to the body…. Not good! Can cause a fire

Glad you found it,
Make sure it’s all clean when you re connect

 

[Running an Explorer]

Yeah that ground is just kinda important lol
There are only 3 connections from the - side if the battery one to the frame one to the body and one to the engine

The frame and engine ground are sometimes the same wire

Without the big ground hooked up everything on your truck is trying to find a ground through the one small
Lead to the body…. Not good! Can cause a fire

Glad you found it,
Make sure it’s all clean when you re connect

Yes, thank you, I used a brass wire brush to get all that debris off.