maddydaddy

Just took the 944 S2 out for a nightime spin and found the wierdest thing. under full throttle the headlights seem to dim at 5,000 rpm and come back if I let up. At first I thought it was just the car rocking back under acceleration then rocking forward as I let up, making it seem like dimming and brightening, but the dash lights seem to do it also. Any thoughts? Is my alternator going bad? Voltage reg?

James Reeser
89 944 S2

rberry951

Hey James,

What does the gauge do when this happens?

Graufuchs

Check belts....and voltage regulator....VOLT reg is ussually the culprit if I rember correctly.

maddydaddy

Will have to go out tomorrow with a friend or in the middle of nowhere. Things happen pretty fast at that rpm to check the lights, dash lights, volt meter, WB o2, etc. Will report back what I find.

V2Rocket

Mine do this too, but I've found its just the fans turning on up front to cool the radiator. Sudden extra draw of current dims them for a second but they return to normal within a second.

maddydaddy

O.K. did some more checking and at about 4600 to 4800 the volt gauge starts to drop and it gets as low as 12v or so by 5000 and seems to stay around there. So us this the volt reg? or the alternator? Is this my punishment for not putting the "cooling" hose back in for the alternator when I did my timing belt?

James Reeser
89 944 S2

rberry951

well, could be the regulator, alternator, or as I believe someone mentioned maybe the belt is a bit loose and slipping at high rpm. But you know when I think about it, now I wonder if it is possibly the correct behavior for the regulator to 'reduce' charging or cut out at a particular rpm/amp level as not to over charge the circuits. I've never looked into this, but I suppose it is possible. Maybe you're just the only person that ever noticed it!

Russell

maddydaddy

Well I ordered a Voltage Regulator and Alternator to replace the old ones. I tend to take the "bomb" approach when fixing problems on my S2, just fix everything that may remotely have a chance of being the problem or ruining a track weekend. I'll let you know if that did it.

James

Hans

you might want to consider:
- cleaning up the grounds on the frame rail
- checking the connectors on the short wiring loom to the lamp units
- checking the loom as well for continuity since this section is flexed every time the lamp pups up and down
- trying to get one of IceShark's wire harnesses for the front lights. The increased wire size and the additional repays will help reducing the voltage drop over the 9rather under sized) OEM wires

TakeCare

maddydaddy

Great ideas, thanks!

James