03 Explorer Strange Electrical Issue

[txpolaris]

I have a strange issue with an Explorer that belongs to a friend of mine. The positive battery terminal was in pretty bad shape so he asked me to change it for him. I cut the old terminal off and replaced it with a new one from the auto parts store. Truck starts right up now with no problems.

Now when you drive the truck, if you press the throttle past approx. 20% the lights on the dash start to flash, the security light on the dash flashes and the engine falls on its face but does not die. As soon as you let off of the gas pedal, everything goes back to working. As long as you don't press the gas pedal past that point it will pick up speed and shift gears. I got it up to about 45mph but as soon as you pass a certain point with the throttle, it just seems to freak out. Any ideas???

 

[Duranged84]

Does it do it in park or neutral too? Check both ends of main ground cable? Check small ground on passenger head to firewall? Never seen one do that. Was it doing anything like this before replacing the terminal end?

 

[txpolaris]

It only does it in gear. No problem in N or P. It was not doing it before the battery terminal was replaced. It makes no sense at all.
I checked all the grounds I could find. I even checked the ones behind the passenger kick panel. Everything is good and tight and they all have continuity. It feels like the cat is plugged up but that doesn't explain the idiot lights coming on and the theft deterent light.

 

[txpolaris]

I did notice today that the needles on the dash move around erratically when you first start it then they level out. He said it has been doing that for a long time. Maybe another symptom of whatever is causing that?

 

[Number4]

Perhaps the alternator is acting up. The fact that the cable connector was so corroded tells you there is a lack of charging occurring. Or the vehicle has set for a long period without being used.

Also, if the cable end was that bad, the cable itself is probably full of corrosion. This will also reduce the alternators ability to charge the battery. It'll lose flexibility if this is true, or you can cut it open and look for green or dark brown copper. Just replace the whole cable.

The more load on the vehicle, the more the alternator puts out. If it can't put out the current volts/amps and it the cable prevents it as well, you'll have issues.

 

[txpolaris]

The cable was very corroded when we stripped it back to install the new end. You could be on to something Number4. I am going to replace the cable this weekend. It needs to be done either way since he has no plans of getting rid of it anytime soon. I appreciate the help and will update this when I have more info. If anyone thinks of anything else, please chime in. Thanks!

 

[txpolaris]

Still not sure what the problem was but unhooking the battery overnight seems to have fixed the problem. It's been running fine for 4 days now. I appreciate all the help!