PDA

View Full Version : Alternator like symptoms


slowmaro305
11-20-2013, 08:36 AM
Hello everyone, bought this trilogy marauder this past summer. Has 66,000 miles on it.

This past week battery light came on for a littel while then went off. Couple days later on again. I checked everything, battery cables good, battery tested excellent, alternator was charging perfect. Then a couple days ago battery light came on again, lights started dimming, lost acceleration.

Anyway i put a new motorcraft alternator on. All seems to be well. Just seemed to be weird that everything tested good.

Im new to these cars, is this a common problem? Maybe something with the trilogy is harder on them, because the new alternator had some type of clutched pulley on it that i had to remove.
fastblackmerc
11-20-2013, 08:46 AM
The alternator might have been failing under a load.
Curless
11-20-2013, 08:50 AM
Agreed, your alternator tests should always be done under a load...
lifespeed
11-20-2013, 09:36 AM
Alternator brushes do wear out. One should expect the alternator to start failing by 150K (approximately, you don't need to tell me about your 200K alternator that is still working fine ;) ).

The failure mode for worn brushes is indeed intermittent, works OK under light load, not heavy load, etc.
03sport007
11-20-2013, 01:56 PM
Something to think about with the trilogy is the alternator is spinning backwards. The guys that rebuilt my alternator said because the cooling fins are turning the wrong direction this will adversely effect the alt ability to disperse heat. That coupled with alt location(not a lot of airflow) make for alt that will run hotter then It would it the stock setup.
justbob
11-20-2013, 05:24 PM
Jiggle the Alternator wire that runs back to the battery. Trilogy cars have extended wiring and I know of at least one that shorted out right at the extension connection.


Self proclaimed Builder Of Badassery.

Buy it, Break it, Build it BETTER.
"Since 2004"
slowmaro305
11-20-2013, 06:35 PM
Agreed, your alternator tests should always be done under a load...

I did perform a load test with a snap on tester that we have at the shop. Thats what was throwing me off. Either way seems to be working properly now with the new motorcraft in it.
slowmaro305
11-20-2013, 06:37 PM
Jiggle the Alternator wire that runs back to the battery. Trilogy cars have extended wiring and I know of at least one that shorted out right at the extension connection.


Self proclaimed Builder Of Badassery.

Buy it, Break it, Build it BETTER.
"Since 2004"

I will take a look at the wiring anyway even though its working ok now. I did not know the harness was extended for the trilogy. I guess it had to with the relocation of the alternator. Thanks for the tip!