RPM WS6

iTrader: (3)

It's not that this issue is specific to the automatic trans itself, it's because the idle speed (especially in gear) for an auto is much lower than an M6.

Stock M6 idle rpms: 800
Stock A4 idle rpms: 650 P/N, 550 in gear

But, as you have a bigger cam now, I'm sure your idle speed was raised during the tune.

You probably need a new alternator. That's exactly what mine needed when the lights started to pulse, and the problem was completely solved with a fresh factory replacement unit. People around here like to pimp "the big 3"/truck alternator/etc. as the requirement to fix this, but they are missing the bigger picture; these cars rolled off the assembly line without flickering/pulsing lights, so why would they suddenly *require* a truck alternator to fix this issue later down the road? The truck unit is a nice way to get an amperage boost if you need it, but the lack of one is NOT the reason for pulsing lights - something else is wrong when that happens (bad alternator, poor grounds or other connections, etc.)

Granted, you are straining the system with the UD pulley, so in your case a non-stock solution might be the answer. As wssix99 mentioned, overdriving the alternator may or may not fix your issue here, since the alternator appears to be on the way out anyway. The best solution may be a fresh (good quality) alternator that is also overdriven to compensate for the crank pulley.

I'm not sure how a bigger alternator pulley would help with this idle charging issue, as this would only serve to spin the alternator even slower. You'd want a smaller alternator pulley to restore the factory ratio/relationship between crank and alternator pulley sizes.

wssix99

iTrader: (5)

^^^ Right. The overdrive alternator pulley should be smaller than the original one.

TORK?

iTrader: (27)

I had this same problem and it turned out to be a bad ground from the battery.

I would check all the "free" things people have told you here. If everything worked fine before, your existing parts probably aren't bad.

If my alternator goes, I'm replacing it with a stock one. Unless you're running prerunner lights and 5 stereo amps there's no need to spend extra money on a different one.

I agree with RPM on the alternator pulley. Smalley pulley = spins faster = works more. Rememebr the old school sbc and 5.0 underdrive kits came with smaller alternator pulleys for this same reason.

senicalj4579

iTrader: (41)

If my alternator was the pronlem and going bad wouldnt I see lower voltage battery readings? Im seeing 13s.

RPM WS6

iTrader: (3)

When my original one started pulsing, it bounced within the 13s under a basic load. Several different things can fail inside the alternator, so it may still provide a charge even though voltage regulation has become unstable.

senicalj4579

iTrader: (41)

Ok. If I brought the alternator to autozone would their test be able to tell its bad even though its showing 12.8-14.1 volts?

Can voltage regulators be changed on these alternators or would I need to have a whole new alternator?

Thanks

RPM WS6

iTrader: (3)

I'm not sure. I've learned through past experience that these bench tests don't always tell the tale. I've had alternators that tested fine on their bench, but then output poor voltage once fully heated in a running engine. The test isn't long enough to expose problems other than a truly dead unit.

I didn't even bother having mine tested when the pulsing started, I just swapped it out and the problem was solved. It was the most likely reason, but if that had not solved my condition then wiring would be the next most likely culprit. This was on a stock car with stock pullies though.

Voltage regulator is internal to these alternators, but if you know how to rebuild an alternator than it can certainly be changed. If not, you would need a new unit.

wssix99

iTrader: (5)

I'd be surprised if their testers are this sensitive. I'd just expect that the tester would look for out of range measurements outside of 12-14. In order to find fluctuations in this range, I'd expect they would need more sophisticated equipment. (BTW - I'd also expect a voltage regulator to fail more dramatically - you are probably just the lucky 1%.)



Check out Alternator Man! He has videos that show how to do this as well as at-home tests of the Alternator's workings.

http://www.youtube.com/alternatorman

senicalj4579

iTrader: (41)

Thanks Ryan I think I just might replace it. I know everyone is gung-ho about truck alternators but could you recommend where and what to get? What are you using?

Maybe I should investigate the alternator pully as well?

senicalj4579

iTrader: (41)

Are you saying you dont think its the alternator/voltage regulator?

RPM WS6

iTrader: (3)

I bought a stock F-body alternator from GM, as this has been my pratice for modern cars for quite a while now. My experience with Auto-Zone type rebuilds has been very poor (there is a reason they are so cheap), so I don't even bother with them. If you don't mind changing them often, then I suppose the lifetime warranty makes it worthwhile. GM alternators are extremely expensive if you don't have some sort of business account with a dealer though.

For older cars, I always use Powermaster, as they build excellent aftermarket units using stock shells. But I don't believe they make one for LS1 engines yet (I could be wrong, haven't been in the market for one in a while). There might be other aftermarket companies that build nice units for LS1 as well, and that are cheaper than going to a GM dealer. But the junk you get at Auto-Zone is not going to last like OEM or a good aftermarket unit.

An overdrive alternator pulley that restores the proper ratio between the alternator and crank pullies would certainly help with idle voltage, even with a brand new unit. You just have to be careful to not over-spin the alternator with too small of a pulley and very high rpms.

How much this helps will depend on what your idle speed was set to with the cam tuning. With a stock A4 idle speed, the difference should be pretty noticeable. As idle speed goes up, the difference will be less noticeable (all else being equal).


I think he just means that usually when the voltage regulator goes bad, you end up with a more catastrophic failure of charging (either high or low), rather than just minor surging. But failures of this type can and do happen, it's just not as common as having the alternator simply fail to charge altogether.

If you feel up to the project, you could learn to rebuilt them yourself as wssix99 suggested. One day I'd like to try this, but I haven't gotten around to it yet.

wssix99

iTrader: (5)

Exactly correct. I'd also echo all of RPM WS6's other comments above. There are tools to tell exactly what is going on, (Oscilloscope) but they would cost way more than an alternator and take a little while to master. My personal litmus test is - if the part is old enough that it could go on me at any time, I don't worry too much about replacing it as a guess to what's going on.


When I replaced my last alternator, I purchased a new unit and saved the core so I can rebuild it when I have a proper garage and bearing press. Hopefully that stuff is coming soon...

senicalj4579

iTrader: (41)

How about this powermaster? http://www.ws6project.com/user_stor/...mp-alternator/

RPM WS6

iTrader: (3)

Well, it seems that they *do* make one for the LS1s now.

My experience with them has been great, but I've only owned their 10SI style for older GMs. I have one on my Nova right now, and it has been impressive to say the least. It's the same amperage rating as the one it replaced (65), but voltage output is much more stable and always stays in the ideal range even at idle. They put a smaller diameter pulley on the 10SI which compensated for my smaller crank pulley, this was important because I have some extra electrical loads that would not have been present on this car stock (electric fan, high energy ignition + CD box, extra gauges, better radio and speakers, etc.) The 10SI is limited to 6k rpm with this pulley size, but that's not an issue for me since the engine is a mild SBC that peaks in the low-mid 5k range anyway.

You may want to check with Powermaster and see if a smaller pulley was used on their LS1 units, and if so, what the max operational rpm limit is.

senicalj4579

iTrader: (41)

Well, its been in ws6store catalog since 2008 and through search I can see they are pretty popular. I just ordered one. Hopefully it fixes my flickering lights. The flickering lights are strange though because its always consistant aat night as if the lights hold a beat to a song. But in daylight I cant for the life of me see them flickering other than at startup. Ill update when I get it/install.

Thanks guys.

RPM WS6

iTrader: (3)

Yeah, looks like the part number has been available for a while but it's not shown in the alternator overview on Powermaster's site. However, they do have it listed in their complete catalog; guess I should have checked that before....haha.

I would not hesitate to try their unit on an LS1. If I ever need another, I will get one myself.

senicalj4579

iTrader: (41)

Yea I did notice on the web site there was nothing on ls1s. Your right.

Cant wait to get this alternator. Im curious to see if the old alternator had anything to do with the surging/stalling issue the car has as well as the flickering lights. I would have to believe its possible

senicalj4579

iTrader: (41)

The Powermaster fixed the flickering lights. Its a nice piece.


Good #s.


But if you look closely the stock alternator pulley is bigger than the powermaster.


The smaller alt pulley lengthens the belt. Would you feel comfortable with the belt if your tensioner mark showed this?


I drove it and seems fine but I may just get a shorter belt to be safe.
How much shorter of a belt would you say?

RPM WS6

iTrader: (3)

I imagine you already have a smaller belt due to the crank pulley swap? Even with the slightly smaller alternator pulley, that belt looks to be marginally tighter than mine is with a stock belt, new stock tensioner and all the stock pullies. I would just leave it.

PS. Glad to see that the new alternator fixed your issue. I figured it would.

senicalj4579

iTrader: (41)

Yes it is a smaller belt due to the UDP.
Alrighty then I will just leave it and see how it does.
Thanks for the help/info