need electrical/charging system help
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Newbie
Joined: Aug 2010
Posts: 1
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need electrical/charging system help
Hello everyone, i have a 2003 lancer OZ rally M/T that i have been struggling with electrical problems for a while now.
quick timeline....
End of May - battery drained while driving on interstate, replaced the battery to get it home... used a dmm to check if it was charging, wasnt charging so i replaced the alternator. Everything seemed fine.
June - had some battery drain issues a few times, some while driving, some while the car was parked. Didnt replace anything because i had no idea what was causing it. everytime the battery would die, i could jump start it and everything would work fine for a random amount of time. (sometime everything would be fine for 2 weeks+)
End of July - driving on interstate, battery drained while driving. had my
car towed to a shop. they checked the battery and alternator and both were fine. after some more testing they came to the conclusion that the ecu was junk and that there were a few bare wires near ecu...they fixed the wiring and i bought a used ecu off of ebay and installed it myself(instead of the 800 they wanted to charge me for a used ecu installed).
Aug 14 - replaced the ecu, the old one had a slight burnt electronics smell around the C-119 plug. started right up.. everything seems good.
so to my question....
What would cause my headlights to be dim from idle to 2500rpm? If i put a dmm on the battery while the car is idleing it reads 11.7V ish, after you rev the engine to 2500rpm + it jumps (instantly at 2500rpm) to 13.5V ish. My headlights never had this before i had all of these electrical problems and im at a loss what to even check anymore. I downloaded the FSM and was trying to figure it out with no luck. Is their a relay or something that could cause this?
oh and the junk ecu did the same thing, so its not the ecu causing it.
any help is appreciated! thanks
quick timeline....
End of May - battery drained while driving on interstate, replaced the battery to get it home... used a dmm to check if it was charging, wasnt charging so i replaced the alternator. Everything seemed fine.
June - had some battery drain issues a few times, some while driving, some while the car was parked. Didnt replace anything because i had no idea what was causing it. everytime the battery would die, i could jump start it and everything would work fine for a random amount of time. (sometime everything would be fine for 2 weeks+)
End of July - driving on interstate, battery drained while driving. had my
car towed to a shop. they checked the battery and alternator and both were fine. after some more testing they came to the conclusion that the ecu was junk and that there were a few bare wires near ecu...they fixed the wiring and i bought a used ecu off of ebay and installed it myself(instead of the 800 they wanted to charge me for a used ecu installed).
Aug 14 - replaced the ecu, the old one had a slight burnt electronics smell around the C-119 plug. started right up.. everything seems good.
so to my question....
What would cause my headlights to be dim from idle to 2500rpm? If i put a dmm on the battery while the car is idleing it reads 11.7V ish, after you rev the engine to 2500rpm + it jumps (instantly at 2500rpm) to 13.5V ish. My headlights never had this before i had all of these electrical problems and im at a loss what to even check anymore. I downloaded the FSM and was trying to figure it out with no luck. Is their a relay or something that could cause this?
oh and the junk ecu did the same thing, so its not the ecu causing it.
any help is appreciated! thanks
Newbie
Joined: Jan 2008
Posts: 53
Likes: 0
From: Vancouver, Wa
Naturally as the vehicle revs higher the voltage at the battery will increase due to the higher output being generated by the alternator.
Could very well have something to do with a bad ground somewhere in the vehicle. I'd get under the hood and wiggle your grounds while you have the DMM hooked up and see if that changes anything.
Could very well have something to do with a bad ground somewhere in the vehicle. I'd get under the hood and wiggle your grounds while you have the DMM hooked up and see if that changes anything.
