Charging Issue
 

Hey guys,

My car broke down yesterday. It started off in the morning where turning it on, it was slow to turn over. Then my battery light came on. As I was driving, the battery gauge started to go down. I drove for about twenty miles and when I reached a red light, the car shut off. I was able to put a new battery in but it fires up and shuts off after about 30 seconds. I took it to a mechanic and he says that the alternator isn't the problem. Anyone have any idea what it might be and how much it will cost to repair it?

Here's the stats on my car: 01 A4 1.8t. ST chipped w/ high flow cat.

Thanks for your help in advance.

Possible to get a second opinion? Sounds like an alternator issue to me.

Do you have a continuity tester? If not borrow one or buy one and test the alternator yourself. If its not putting out voltage, you've found your problem. If it is putting out voltage, then you want to test the leads running to the battery. If you have Voltage at the alternator but not the battery, check your wiring. That would be the first thing I could think of testing. Like Mcgovs said, it sounds alternator related.

Yeah. I was thinking the same thing. Plus when the car shuts off, there's a high pitched tone. I'm beginning to think the guy doesn't want to work on it. He said it's something with the computer but I don't know. I really appreciate the suggestions. I really do. When these cars have issues, I hold my breath in fear of the cost.

I was really worried about working on Audi's myself at first. I guess I was intimidated because everyone seems to make it seem like its such a pain to do. But in all honest the alternator is right at the front of the motor and at the top. Which is much or convenient than some Mercedes/Volvo's I've had my hands on.

Really? I should look up the diy on it and save some money.

Yes sir, I've never had to change one myself. Even though its right on top and in front, you will probably have to pull the front clip to access the bottom bolt and timing belt tensioners. If you end up doing it yourself, it would be a good time to do your timing belt/water pump. I just pulled a front clip on a 2000 yesterday, took about a hour and a half by myself.

Ok,

The car was sitting in the repair shop for almost a week so I had it towed back to my place. Good guys. They didn't charge me for the diagnostics. The car still fires up and runs but after a few seconds the tachometer pulsates between 1krpms and about 400 rpms then shuts off. Battery symbol is still on. Mech said the alternator is fine though. Here are the codes that he pulled:

P1128 Fuel Trim Bank 1 Too lean
P0300-304 Cylinder misfires (Just replace ignition coils today)
P1136 Fuel Trim Bank 1 Too Lean
P0102 MAF Sensor Signal too low
P0130 02 Sensor Bank 1/ 2 Internal resistance too high.

As I'm typing this it's starting to look like I need to clean my MAF and possibly replace my O2 Sensor. Would either of these (or a combination of both) be the culprit for my car not wanting to stay on?

Thanks for the feedback so far. It's really helping out!

Try cleaning the connection to the MAF, if not the connection you can try changing it out. This being bad would definitely lead to loss of power/stalling. I would imagine this could also lead to bad 02 readings. Try cleaning it up and seeing if that helps out at all. I've heard its tough to clean. Should at least give you an idea of weather this is what your issue is or not though. Alternator must be fine if the car has a charge, problem is a bit different than originally described. Post bad and let us know how it goes.

Will do. Hope this leads me one step closer.