Alternator problem?

[spencers]

I replaced my alternator a couple months ago, due to a noisy bearing when its cold outside. Happy to say that the problem was solved. The replacement is a Bosch remanufactured alternator purchased from AdvanceAuto.

Ever since I replaced it, I've been having problems with bogging / hesitation when the RPMs drop to idle. For example, when the clutch is pressed in and I'm at a stop light.

It's EXTREMELY pronounced when the A/C and xenons are on. The RPMs will drop to below idle, then surge back up to about 1k, and repeat indefinitely until I give the car throttle.

However, it's not very pronounced when none of the accessories are on.

My guess--shoddy voltage regulator.

Any ideas on how I should go about remedying this? What would the mafia do?

I'm sure I could take it back to AdvanceAuto, but they'd probably replace it with the same junk, right? I feel like I have dug myself into a hole here. I did what I always say people shouldn't do, and that's buy quality, and have no problems.

The part in question:
http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product__19850481-P_11_R%7CGRPALTSAMS____?cm_mmc=ET-_-Trans-_-RAF-_-General

[telijah]

Regulator sounds likely, have you seen what the voltage is while having the problems?

[Johnmadd]

New parts can be bad out of the box, id exchange it. Have you had your battery tested?

[WOLFN8TR]

Put a meter on it and see what it's putting out. Sounds like the regulator to me. I believe Autozone will check it for free.

[spencers]

Thanks for the replies.

Here's a video. I was parked, car is on. I turned on the air conditioner first, then flipped on the headlamps, then revved the engine. Voltage is showing on the OBC.

The rev bounce in the video is not as pronounced as it has been, but you can still see it occurring.

http://www.youtube.com/watch?v=_R25GRXF-Lo
Sorry it's out of focus

[danewilson77]

That's jacked.

If it were the VR....would one not see other indications? Would lights dim, and get bright?

[spencers]

That's jacked.

If it were the VR....would one not see other indications? Would lights dim, and get bright?

Very true and good point. I do not see dimming lights when this phenomenon occurs.

[terraphantm]

The alternator might be a red herring... How old is your MAF? Mine had similar symptoms when the MAF was dirty, and the car reverted to normal operation when I unplugged it. If I remember correctly, my issue was more pronounced when the AC was on. Maybe your intake got knocked loose when you were working on the alternator? The rev bounce might just be because the car has more load on it

I can't see the video though

[danewilson77]

The alternator might be a red herring... How old is your MAF? Mine had similar symptoms when the MAF was dirty, and the car reverted to normal operation when I unplugged it. If I remember correctly, my issue was more pronounced when the AC was on. Maybe your intake got knocked loose when you were working on the alternator? The rev bounce might just be excuse the car has more load on it

I can't see the video though


This is a good point. No codes though....which may yield more data.

[spencers]

The alternator might be a red herring... How old is your MAF? Mine had similar symptoms when the MAF was dirty, and the car reverted to normal operation when I unplugged it. If I remember correctly, my issue was more pronounced when the AC was on. Maybe your intake got knocked loose when you were working on the alternator? The rev bounce might just be excuse the car has more load on it

I can't see the video though

I was just thinking MAF. It's as old as the car. Probably never cleaned. I'll have to give that a shot.

Was also thinking about hooking up the computer and resetting adaptations. Not sure if that'll help though.

Here's a direct link to the video. http://www.youtube.com/watch?v=_R25GRXF-Lo

[Johnmadd]

Not sure how much this relates but...I have had stuttering in my e30 for a while on first start of the day and it got worse and worse. I got a code for the mass air flow meter (equivalent) and reset and never came back. Then 2 months later it gave me a code for lambda system. Changed the maf because I had an extra, problem solved.

Does anyone near you have one you could swap in to test with?

[danewilson77]

Just checked mine. 14.0v at idle and while driving. Zero fluctuation.

This got me to thinking. Why does the idle "hunting" cause your voltage to fluctuate? I don't think it should. Maybe it is your VR/battery/other electrical issue.

I like cleaning MAF sensor first.

FWIW... When I change my oil/filter... I clean my AFE intake filter and my MAF sensor. Yours could be pretty dirty.

HTC Thunderbolt+TT

[spencers]

Not sure how much this relates but...I have had stuttering in my e30 for a while on first start of the day and it got worse and worse. I got a code for the mass air flow meter (equivalent) and reset and never came back. Then 2 months later it gave me a code for lambda system. Changed the maf because I had an extra, problem solved.

Does anyone near you have one you could swap in to test with?
Hmm.. Sister has a 323Ci and a friend has a 330Ci. Don't think either of those will work. Shucks

Good idea if cleaning doesn't solve it.

[spencers]

Think I found the problem..
http://img39.imageshack.us/img39/8914/img0710x.jpg

Upper intake boot is torn. Discovered when cleaning the MAF. I sealed it up pretty damn good with some electrical tape and took a drive afterward with the A/C and xenons turned on. Car still hunts for idle. However, I noticed that the car actually finds idle after a few bounces.

ADDITIONALLY, the small vacuum tubing going from the "F-fitting" disintegrated. I replaced it with some 5/32" vacuum tubing.

I may try resetting adaptations tomorrow. In the mean time, I'll order a new upper intake boot.

Either way, I'm still baffled why the idle still bounces.

[Oli77]

Couldn't a dirty ICV also affect stability of idle?

[danewilson77]

Couldn't a dirty ICV also affect stability of idle?

But wouldn't VR still "regulate" voltage?

HTC Thunderbolt+TT

[Oli77]

Ok so no matter what RMP, the VR just regulates the voltage. I can dig that.

But today, as I was reading OBC code 19.9.0 (for your entertainment :)), I got numbers that where fluctuating. They were not fluctuating as much as Spencer's car though. Perhaps this is the VR signature?

Mine does the 14.1-14.2 V at idle and stays there. If i turn lights on it very briefly goes to 13.5 V or so. I will try AC tomorrow.

[Jorge86]

My alternator just went out today. In the last couple of days I could feel the rpm dropping. Some hesitation at idle. Will replace this weekend. Oem or aftermarket is the question. I would also like to install a volt gauge somewhere so that I could see if it's not charging in the future.

[Oli77]

Read the voltage from the sensor through your on-board-computer (left knob). Read code 19.9.0

[danewilson77]

Read the voltage from the sensor through your on-board-computer (left knob). Read code 19.9.0

Hehe...

HTC Thunderbolt+TT

[Oli77]

Link it and get more traffic why don't you?

[danewilson77]

Link it and get more traffic why don't you?

In for quality, not quantity :)

HTC Thunderbolt+TT

[Oli77]

lol

[Hornung418]

So it seems that you have two separate issues? Did I read this thread right? And your sister's MAF should work with your 325 MAF, Spencer.

[spencers]

So it seems that you have two separate issues? Did I read this thread right?

I have no idea. Hoping its all connected in some way.

I'm going to clear adaptations values this morning with my diagnostic laptop and cable.

[terraphantm]

Just checked mine. 14.0v at idle and while driving. Zero fluctuation.

This got me to thinking. Why does the idle "hunting" cause your voltage to fluctuate? I don't think it should. Maybe it is your VR/battery/other electrical issue.

I like cleaning MAF sensor first.

FWIW... When I change my oil/filter... I clean my AFE intake filter and my MAF sensor. Yours could be pretty dirty.

HTC Thunderbolt+TT

What about when you turn accessories on? Mine is pretty stable at idle and while driving... but if I really load the electrical system at idle (rear window defroster, headlights, highbeams, foglights, rear fogs, brakes, and whatever else I can think of), the voltage does drop a decent bit at idle. Goes right back to 14 at higher revs though. Others I've talked to indicated it's normal for the voltage to drop a bit at idle.

[Hornung418]

So the real issue is now the hunting for idle, which should be fixed with the new boot and a thorough cleaning of the MAF, ICV and TB.

[spencers]

So the real issue is now the hunting for idle, which should be fixed with the new boot and a thorough cleaning of the MAF, ICV and TB.

Hope so. I cleaned those not too long ago, but maybe the tear in the boot introduced dust and junk.

[Oli77]

So clearing the adaptation values did not fix the idle pumps?

[spencers]

So clearing the adaptation values did not fix the idle pumps?

Just tried it this afternoon. It seems to have helped somewhat.

It now looks like the strongest idle bouncing occurs when the car is first started. After driving for a minute or two, it becomes less apparent. Odd huh..

[terraphantm]

Just tried it this afternoon. It seems to have helped somewhat.

It now looks like the strongest idle bouncing occurs when the car is first started. After driving for a minute or two, it becomes less apparent. Odd huh..

When was the last time your O2 sensors were changed?

[spencers]

When was the last time your O2 sensors were changed?

Both pre-cat's were changed 3/15/2011

[terraphantm]

Okay it's not that then. Well... I'd see what happens after replacing the intake boot and giving everything a thorough cleaning (and perhaps trying your sister's MAF).

[spencers]

Upper intake boot replaced. The o-ring between the MAF and intake housing was replaced as well.

No change. I'll attempt an ICV clean this weekend.