Ford Escape Altenator Light comes on.

[mkscw]

I bought a used 02 Ford Escape V-6 for my college son. When you accelerate, the battery light comes on until you back off of the gas peddle. I have put a meter on the battery and when the car is in drive and you give it gas holding the car with the brake, the batt. light come on and the voltage at the batt. drops to about 12V from 13.5-8. I have replaced the Altenator (it checked good) and the battery and have added grounds from the battery to the block with no luck. on occasion (few), this problem goes away for a while and everything is fine. I have checked all of the connections and cables and such and am at a loss.
It has come on and stayed on a few times for so long that it acually has drained the battery and died. If you let it sit for a while it will usually start again and the same cycle starts over.
It appears that the altenator is either being loaded heavily or is shutting itself off but I am not sure.

HELP????? Or should I shoot the thing. It runs good and is in good shape otherwise and I can't afford another vehicle for him. I should add that changing the altenator in that car again is tough for this old man. It took me all day the first time.

If you have any suggestions please help, and thank you.

[wptski]

Originally Posted by mkscw

I bought a used 02 Ford Escape V-6 for my college son. When you accelerate, the battery light comes on until you back off of the gas peddle. I have put a meter on the battery and when the car is in drive and you give it gas holding the car with the brake, the batt. light come on and the voltage at the batt. drops to about 12V from 13.5-8. I have replaced the Altenator (it checked good) and the battery and have added grounds from the battery to the block with no luck. on occasion (few), this problem goes away for a while and everything is fine. I have checked all of the connections and cables and such and am at a loss.
It has come on and stayed on a few times for so long that it acually has drained the battery and died. If you let it sit for a while it will usually start again and the same cycle starts over.
It appears that the altenator is either being loaded heavily or is shutting itself off but I am not sure.

HELP????? Or should I shoot the thing. It runs good and is in good shape otherwise and I can't afford another vehicle for him. I should add that changing the altenator in that car again is tough for this old man. It took me all day the first time.

If you have any suggestions please help, and thank you.

The battery voltage should be like 14.5V when running which shows it's charging. You'd need a current clamp probe to determine is there is a heavy load of some kind. It's been posted here that on some vehicles the PCM controls the charging rate.

[theoldwizard]

I'm betting the replacement alternator was not a Ford part. I have heard of cases where aftermarket voltage regulators (inside the alternator) don't "play well" with the PCM (which can turn it off). I can't prove this.

My only suggestion is to replace the voltage regulator with a genuine Ford part. No guarantee.