ArcticSteve

I've got this issue in my S2 that after the motor gets up to operating temperature and run for a while it will start to lose power drastically, fuel pressure drops and the voltage drops at least 1.V to 12.25 to 12.5 volts from a steady 13.5 V at idle. After a one hour shut down, engine bay still plenty hot, voltage is back to 13V (not 13.5) and it will run again for a short period before repeating the process. At this time, when it's barely running the volts are back down to 12.25-12.50 V. Dead cold the voltage is always 13.5V idling.

I have checked most accessible grounds. Changed fuel pump. Changed fuel pressure regulator. Swaped battery.

Car has 220k miles. Parts history unknown. Fuel pump was definitely original.

So I was thinking it's time to mess with the alternator. But does this sound like a voltage regulator issue?

And when you get a reman alternator I assume the voltage regulator is new?

Thanks

bearone

i see low 14's to upper 13's when cold and a needle width below 14 at operating temp with a/c and lights on.

probably brushes.

i did a bosch reman a while back and it came with a new vr.
brushes in old alternator were about 1/16", if that.

87951
95sl320 dd

fbgh2o

You might also consider new main cables for the starter, alternator and grounds. Makes a huge difference. Mine always shows just under 14V at start and under operation.

bearone

i forgot, i did the batt cables at the same time, cleaned stuff up and eliminated a lot of problems.

87951
95sl320 dd

ArcticSteve

OK guys. I have been getting many signals from my previous threads about old/faulty wiring. So I yanked the negative battery cable to the bell housing. At the bell housing the cable was pretty green. So I'm gonna get a new one made up and I will get around to the starter/alternator cables after I get the new one in.

Here's a pic of the cable. I did the clutch this past winter, so I obviously distrubed the cable. It's was pretty brittle before I peeled off the plastic coating which was split close to the bell housing end.

Thanks for the replys.

bearone

that's not much, mine looked like a swamp under the cracking insulation.

87951
95sl320 dd

ArcticSteve

Issue finally resolved. Repaired the battery cable and reinstalled. Idling voltage is best yet at 13.8 volts.

Thanks for the replies.