Another alternator question?

[XJjosh]

Ok, so I have searched and found nothing to do with what I am talking about. I have a 2001 XJ. When I drive the voltage gauge says 14-15v. Occasionally it will peg to 19 and the check gauges light comes on. It will usually stay on until I come to a stop or it will turn off by itself. Or my radio will just shut off while I am driving or when I am putting the windows up. When the windows go up the needle will go down past 14v and the windows go really slow. And the interior and headlights will flicker all of the time. I had the alternator checked on the car at advance auto and he said at idle it was putting out 2.5 amps roughly and 14volts. He said it might be the alternator but I talked to San Hose Generator to order a new one and said that it sounded like the regulator (which is external). I dont get any other symptoms and no check engine light or codes. Please help!! Thanks!

Josh

 

[stewie]

just pulling a comment out of my butt, but did you check the grounds. i mean pull them off and ensure no corrosion between the ground and the sheet metal?

 

[5-90]

Grounds are my first thought as well. Since you're getting 14-15VDC, I'm guessing your regulator is up to scratch (which, if you have the ND unit, is actually in the PCM!)

With your 2001, the first things I'd check are the mains grounds off the battery - and when you pull the lugs off the sheetmetal to check them, have a wire brush handy, as well as a tube of Ox-Gard (check your hardware store.) While the lug is off, clean a small patch of sheetmetal (no paint! Just a little larger than the lug's "footprint" - no larger than a postage stamp) and apply Ox-Gard. If possible, a new screw isn't a bad idea - I'll usually replace body ground screws every time I pull them out.

Also, check your battery terminals. It's less of a problem with Gel Cells, but the lead-acid batteries do tend to "outgas" just a bit, and this causes terminal corrosion. If nothing else, you should disassemble and clean battery terminal connections 2-3 times a year, and check them monthly at least (a simple visual inspection will do - no need to tear them apart unless you see corrosion.) Have a "mirror-on-a-stick" and a small flashlight when you do - corrosion usually starts on the bottom of the clamp.

Also, make sure the alternator mount is nice and clean - metal-to-metal contact is the key here - because that's how your alternator grounds. I think your battery-engine block ground ends up somewhere down near the alternator - make sure it's clean as well.

Did I miss anything? Oh - thanks for giving Rod a call. The more business we can do for him here (he's a stand-up guy!) the more options I can try to talk him into later...

5-90

 

[Dave in Eugene]

If it has a Chrysler SMEC I think the regulator is in that And there is probably nothing wrong with it.

An alternator will not work right without a good battery, and it sounds to me more like a problem at the battery than anything else. The posts and terminals should be cleaned any time you think about it. Then check the battery with a hydrometer if you can. All cells should be near the same specific gravity and at a full charge that is nearly 1.300. If you have a low cell I'd suggest it is open, which will present a lighter than normal load at the alternator and make the voltage high throughout the system, while at the same time fluctuating quite a lot when different loads are placed on it. At the the heart there will be low actual battery voltage which will limit the alternator's actual output power and though you see more than 14V, when you put a load on the voltage goes way down and the system being run (like the PWs) doesn't get enough juice. Sounds exactly like what you have described.

With the funny thing going on with the winders I'd also look at the body grounds, but that's been said.

 

[XJjosh]

See, I cant check the battery. I have an Optima red top and the terminals are spotless!!!