Wipeout

Noticed the alternator light glowing very dimly last night - dim enough that I'd never see it in daytime. I had the headlights, defroster, and the air all on (very wet night last night, trying to keep it from fogging up). The light got brighter (not by much, but still brighter) as revs increased.

It was still barely visible. Went out this morning and took a look at it. With the car on, I get a reading 13.7 on my multimeter at the battery. The alternator light only starts glowing when the headlights get switched on. I am using the rennbay harness wired directly to the alternator. Voltage regulator is about a year old, alternator is out of schwank's '83 parts car. I had an alternator issue with my original alternator about a year ago. Belt doesn't seem to be very loose. I haven't changed the accessory belt, but did get one to put in when I do the timing belt and rollers soon.

Only thing I didn't do was check the tightness of the connections on the back of the alternator, as that requires getting the airbox off and I know I'm doing the belts soon.

Anything missing? Could this be a loose connector on the back of the alternator or am I looking at impending alternator failure?

dougoh

sounds like the alternator is shot ...same thing was happening to my old 86 951 on the way to the track ...it took about 2 1/2 hrs of driving before i lost total power

athens944

voltage regulator is another possibility

jtsporsche

OT: athens944 - what kind of car is that in your avatar?

John_AZ

Second the voltage regulator. Check the brushes and if they are 1/4 inch long or less replace. Before you install the new one, dress the brass brush ring on the shaft. BTW, I did this and the light went out. Check the battery charge for a couple of weeks and if it still goes down the next answer is get a new alternator. I did this also and got a 115 amp from EBay for $99 ($25 ship-no core). My logic was that standard is 90 but our cars have more resistive wiring and components. No more problems.

GL
John_AZ
1988 924S + 1987 924S DD

ELLSSUU

Bugeye Sprite

http://www.empowercoach.com/bio3.htm

schwank

Actually I am pretty sure he has a new voltage regulator in the alternator. His last alt died and so he has the one out of my old 83. He swapped in the new regulator at that time.

Maybe that thing is shot too...

athens944

It is a 1960 Austin-Healey "Bugeye" Sprite. I finally got this one back on the road. A fun car in a different way.

FRporscheman

Darren,
My 944 has done that for as long as I can remember and it's never been a problem... I just chalked it up as an early 944 quirk. If you pin down the cause and fix, I'd be eager to know what I should replace!

Wipeout

Arash,

Thanks! I noticed during driving this evening that it's only when I've got EVERYTHING on - air is on high, defroster is on, wipers are on, lights are all on, everything. It wouldn't much surprise me that it's an "early" quirk.

Schwank is correct - as I mentioned I have his '83 alternator and a brand new voltage regulator in it. I still have my old alternator, I should probably have it rebuilt or use it as a core... Speaking of, what time are you guys at the track tomorrow, E?

Luis de Prat

Did you try tightening or replacing the accessory belt a little? That light is also indicative of a slipping alternator belt. BTDT

marky522

Take you car to your local parts store and have them load test your alternator, i would guess its out put is getting low. A simple test you can do at home is, start the car and turn on all of your loads (lights, fans, defrost, radio etc) and check the voltage at your battery.

Mark

Wipeout

Haven't messed with the belt yet - as mentioned above I'm getting ready to do the timing belt and was going to do all of that at the same time.

I already took a voltmeter to the battery and got a reading of 13.7 with the car on. I don't think I did that under load, however.

marky522

Unless the alternator has completely crapped out you will show good numbers with no load, what you need to see is if you alt can maintain those numbers with a good amperage load on it.

Mark

Luis de Prat

The former is significantly less involved than the latter. A floorjack, pair of jackstands and two 17mm wrenches to adjust the turnbuckle and you're done. I'd give it a shot before replacing the alternator.