Hello All. I've searched through many threads that would lead me to believe my battery or the alternator is bad but both are brand new. The car will start and will idle really high (1200 rpm). I'm thinking this may be due to the new 85mm MAF? So I'm sitting in the car and watch the Volt gauge go from just above 13 when I start it down into the red. If I put my foot on the gas and bring the rpm to 2K the volts shoot up to like 15. As soon as I take my foot off it again they start to go back down into the red zone. Now I know the volt gauge isn't that accurate but still. Anyone have any ideas on how I could diagnose / fix this problem. I'm stumped.

 

Take the car to the auto parts store and have them check your alternator and battery. They should do this for free and it will help you to know.....

 

I'm leaning towards a bad alternator. If your battery is shot, then you would have trouble starting the car. Do your headlights dim when these voltage drops happen?

 

I second the alternator. Do you have an underdrive pulley? It can kick your alternator off line at lower RPM's.

 

I'm third for the alternator. The battery becomes obsolete once the car is on, unless the alternator is bad, then it sucks the energy right out of the battery. Your car won't stay on for too long though, it sucks the battery clean and then shuts off.

That doesn't sounds like what your car is doing, so I say bad alternator.

 

I messed with the car tonight and here's what I found. I can leave the car running and it won't die. It will go right into the top part of the red zone and it will pretty much stay there. The high idle is now gone thanks to ditching the 85mm MAF and sticking the stocker back on. Looks like this will be sitting on the shelf until I get a tune. I drove the car around for a bit on the highway and the volts stay right at around 15 when crusing at 60-70. When I take my foot off the gas to slow down for a light the volts drop back down to just in the red zone. I'm not getting any lights but to be honest, I don't know if there is a light that comes on when you go into the red on the volt gauge. I really hate to think it's the alternator since it's brand new (not a reman) but I've heard horror stories on them so who knows. I'm dropping the car off at the shop tomorrow so they can test it and see what's up. Keeping my fingers crossed it's something stupid but I have this strange feeling everyone is right. I'll post up the prognosis when I find out. Thanks again for all the suggestions.

 

Sounds like a bad volatge regulator in the alt. My stocker does this (some times), but even the, it only drops the volts down to ~12v.

 

Wierd, but some alternators will be defective, even if new.