Can a bad alternator cause poor acceleration

[AVIMAX]

I have an '86, 170,000km, all stock except a Steve Wong chip. Recently I had an issue of some hesitation/bucking when accelerating as many others have posted. I replaced the spark plugs, plug wires, distributor cap/rotor, fuel filter and ran a few tanks with injector cleaner. The issue seemed to go away, I haven't noticed any hesitation for at least a month. All seemed OK. Yesterday I drove the car on the highway for about 30 minutes then parked the car for an hour. When I restarted the car, if started normally, but as I pulled away there was terrible hesitation and bucking. I had to accelerate very slowly to keep the bucking to a minimum. I drove home on the highway, just over 100 km/h no problem, but any hint of acceleration caused hesitation and bucking. As I pulled of the highway and pushed the clutch pedal, the battery light came on when the revs dropped below 2K. I thought the car was going to die, but it didn't, I was able to get home keeping the revs up at stop lights to keep the battery light off. Parked the car for the night. This morning is started no problem, but the battery light is on at any engine speed under 2K. Needless to say, I am not driving the car now until I find out what is wrong. The fan belt is tight, so I assume the alternator must be going, or maybe the battery is bad, but would this cause the engine to run so poorly?

[Jaz]

Do check your battery voltage measuremement first- should be 12v and when engine running around 14v, any thing excessive then you have a Voltage Regulator (VR) failure.

Noting that post-'81 Porsches had an internal VR, meaning you will need to tease the alternator out from behind that fan cowling and replace the VR held in place by two hex bolts at the back of the alternator.


Cheers, Jaz