I've put a new alternator, belt and tensioner but the only time the battery will charge is when I rev the engine up.



Kev.

 

It is very possible that the new alternator is faulty.

It would also help to know what year make and model your vehicle is.
And your post is very vague when asking for tech help the more info you can suply the better we can all try and help

 

I forgot to put that info in there didn't I.

2002 F150 Supercrew with the 4.6.

If it is just idoling it runs off the battery only. When a start from a stop or rev the engine the battery light goes off until it goes through each shift the more the battery light comes on then it just runs on the battery it's self.


I'll try to make it get the alternator checked.


Kev.

 

alternator check out good and battery is good. they had to charge it up for me to even do any of these tests.



Kev.

 

Did you also install a new belt?

I would check all the cables and makes sure they are in tact and tight. Any corrosion on terminals and such?

 

yea...doublecheck those all connections. how many volts are u getting at the battery when its running??? i had a taurus that had the insulation was worn thru and would ground out and dam thing would stall. chased that problem for a week. chek every inch of wire.

 

The volts was like 12 or 13 something like that then this loop type deal that they put on there too was reading somewhere in the 34.

I changed the old battery out about 4 months ago and the post and the wires looked like they were almost brand new. I don't remember why I needed to change it but it did test bad.

I'll check over the wires the best I can.
Kev.

 

They are encased in this thick plastic tubing and I didn't see any rubbing or anything like that. There is a fuse able link from battery post to battery post.......


Kev.

 

anyone?


Kev.

 

Now the check engine light has come on too.



Kev.

 

Where did you get the alternator from?

 

Your not running underdrive pulley's are you? Maybe your truck is idling too low to get sufficient power out of the alt when your not driving.

 

Kev, it's pretty clear that your knowledge of the charging system is not at "expert" level. Trying to get valid advice out of us is like going to a blind man for his opinion on what we are looking at.

My (unexpert) advice is to take it to a reputable service center and make sure they guarantee their work. In reading all your posts, you've covered all the points I know about and if I were in your shoes, I'd 'punt". But, get the guarantee!

- Jack

 

Same stock pulleys.


Kev.

 

Myren and me want to know where you got the alternater from? And who checked it and said it was fine? Its a 2002 truck so I doubt it has wiring issue's unless someone's been doing electical work like new radio's or amps or after market lights or something along those lines. Might wanna check where your ground attach's to the engine and but sure its clean. My quess is you just got a bad alternater...........