Voltage dropping at idle
Thread Starter
Intermediate
Joined: Jul 2003
Posts: 33
Likes: 0
From: Germantown TN
Voltage dropping at idle
I recently purchased a 98 coupe (6-speed). I have noticed that the voltage is dropping below 12V when I come to a stop. The voltage will then go back up to around 13.2V after a few seconds. Is this normal? I have replaced the alternator and TPS but it is still doing it. If anyone has had a similar problem or knows what might be causing this please let me know. Thanks.
Burning Brakes
Joined: Jun 2000
Posts: 1,232
Likes: 2
From: Fort lauderdale Florida
Re: Voltage dropping at idle (BlackBlur)
I had the same thing happen to me last year.. The voltage went up to 14.1 one second, down to 12.6 the next. It turned out that the battery was leaking. I would check this ASAP.. The acid went through the AC lines. It was covered under warranty when I had it fixed.
Safety Car
Joined: Jun 2003
Posts: 4,469
Likes: 20
From: Rockville Centre NY
Re: Voltage dropping at idle (Michael b)
Had same thing happen to my '99. It was a leaking battery. If allowed to continue, the acid could fry your computer which is located below (inside front wheel well). I was lucky - all that was involved was cleaning things up and replacing battery under warranty.
Thread Starter
Intermediate
Joined: Jul 2003
Posts: 33
Likes: 0
From: Germantown TN
Re: Voltage dropping at idle (c5grandsport)
Thanks so much for the information. Pulled the battery tonight and sure enough it was leaking. I cleaned up the acid and it had not made it to the computer or any of the wiring. I installed a new battery and took it out for a spin. The voltage was still dropping but not as bad. Do you know if there is a time period for the computer to "reset"? Hopefully this has fixed the problem.
Melting Slicks
Joined: Aug 2001
Posts: 3,050
Likes: 124
From: Wichita KS
Re: Voltage dropping at idle (BlackBlur)
...... Pulled the battery tonight and sure enough it was leaking. I cleaned up the acid and it had not made it to the computer or any of the wiring. I installed a new battery and took it out for a spin. The voltage was still dropping but not as bad. ......
Burning Brakes
Joined: Aug 2000
Posts: 889
Likes: 0
From: DFW tx
Re: Voltage dropping at idle (mapman)
You may need to replace the cables. When the battery leaks, acid comes out of the positive terminal and can corrode the cable. You may want to inspect it.
Also, if you have not already, I would recommend pulling the tire and removing the inner fender so you can get a good look to see what the acid got to. From the top it is not always obvious how much damage has happened.
Also, if you have not already, I would recommend pulling the tire and removing the inner fender so you can get a good look to see what the acid got to. From the top it is not always obvious how much damage has happened.
Thread Starter
Intermediate
Joined: Jul 2003
Posts: 33
Likes: 0
From: Germantown TN
Re: Voltage dropping at idle (Jeff Jeff)
Thanks. The cables will be replaced today, did not even think to do that. I took the front tire off and removed the inner fender to make sure everything was okay and all acid was removed. Thanks again for the information.
Melting Slicks
Joined: Aug 2001
Posts: 2,753
Likes: 1
From: Fishkill NY
Re: Voltage dropping at idle (BlackBlur)
I had this exact same thing (to the "T") happen to me.....!!! My battery was leaking and I had two bad grounds, one at the battery and one to the frame. I fixed everything and I'm now waiting for the new optima battery to show up.
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Thread Starter
Intermediate
Joined: Jul 2003
Posts: 33
Likes: 0
From: Germantown TN
Re: Voltage dropping at idle (SLICKMAN)
I just replaced my battery cables. My new battery reads 13.5-13.6 at idle on the DIC. One thing I have still noticed is that when the fan kicks on when I am at idle the volts drop down to 11.8-12.2 (with the AC and headlights on). With no accessories on it drops to around 12.5 then jumps right back up to around 13.2-13.5 within seconds. Is this normal for this big of a drop? When I am driving the volts seem to stay pretty consistant around 13.5V. Similiar drop in volts when AC is first turned on. Thanks.
Le Mans Master
Joined: Aug 2000
Posts: 5,294
Likes: 2
From: Suffolk, Long Island NY
Re: Voltage dropping at idle (MITCH)
My DIC indicates that my voltage drops below 11 volts at idle, but read at the alternator it's actually higher. I would do this first before replacing anything. Check your battery while your at it.
I have a 98 also.
I have a 98 also.
