Johnboy1065

iTrader: (6)

I have a weird voltage problem. the battery light has been coming on. and when it does my car stalls as if the computer (AEM EMS) isn't getting enough voltage. ALSO I have a serial gauge that reads directly from the EMS and I'll have it set on AFR mode (which is always moving around) and it will stick at a certain AFR for about 2 seconds. as if it's locking up or something. then its as if I get voltage again and it'll run like normal. I've done some reading and heard that the battery light usually means the alternator But I've had the alternator and battery checked 3 times and they check to be ok. Do you think I have a bad ground somewhere??? ALSO I have a gretty turbo timer which can read battery voltage and it will ALWAYS read a higher voltage than the EMS will. the turbo timer usually reads a full volt or more higher than the EMS does.

does anyone have any ideas??? maybe a bad ground somewhere??? (battery is in trunk BTW)

also I've seen the voltage get down into the high 10's while riding around. some people say when there is load on the battery it's ok for it to get belwo 14's. but 10's seem kinda low. I don't know a whole lot about batteries.

please help out if ya can

thanks

KcEvil8

iTrader: (43)

did you check the alternator when the battery light come on?

Johnboy1065

iTrader: (6)

yes, I checked it shortly after. the thing its the battery light does'nt stay on all the time. but it seems like the voltages are always kind of low.

KcEvil8

iTrader: (43)

probably a bad alternator. 10volts is too low. a good alternator will show in the 13 volts range. how did you check the alternator?

Johnboy1065

iTrader: (6)

I took it to auto-zone and they had some kind of tester that tested it at idle and also at 2000 rpms.

KcEvil8

iTrader: (43)

is the battery lights on when they test it?

KcEvil8

iTrader: (43)

u said ur turbo timer have a built in battery gauge right? why dont u monitor the gauge when the battery lights come on and see if the voltage is too low or too high.

Johnboy1065

iTrader: (6)

nah the battery light is usually not on while they test it. it kind of comes on and off at different times. Yes it does seem like it gets low. BUT the turbo timer and the EMS read different voltages. Whats the lowest it should get under normal driving conditions anyone know???

KcEvil8

iTrader: (43)

it should never go under 12volts

Johnboy1065

iTrader: (6)

on the turbo timer it will get down to 12.0 but I'm sure it goes lower than that because thats when the battery light comes on and the car stalls for a second then it's driveable again after that. But on the EMS it reads around 10.8-11 when that happens.

RSGuy

iTrader: (12)

dude, I am having the same EXACT problem with my car. It has the EMS also. I am really starting to think it's the alternator. Might be time for a HO alternator for me

topturtle

iTrader: (44)

It sounds like the voltage regulator in your alternator is going bad. Either try to get it rebuilt cheap somewhere or do the autozone swap.

Johnboy1065

iTrader: (6)

yeah its kind of hard to figure out because I went months without having any problems after I got it tuned so it can't be anything with the tune. and I havent added or done anything to my car recently. Prolly is the voltage regulator or something like one person said. let me know if you get it figured out. also by the way i wouldnt be flooring the car too much. if your fuel pumps and injectors arent getting the right amount of voltage you could possibly be running lean.

Johnboy1065

iTrader: (6)

anyone else have any suggestions???

Johnboy1065

iTrader: (6)

I think I found the problem. the stud that the power wire connects to on the alternator wasnt tight enough. I havent had a problem since I tightened it up with voltage loss. hopefully that fixed it. it seems like it did