400hp944

I have replaced the alternator / voltage regulator and battery. The car runs fine and AFRs are correct.
Now the issue - when the lights are turned on my AFR drops from 14.6 to around 12.5 at idle. After driving and when coming to a stop, the AFR drops to 10 and stays there. Turn the lights off and all goes back to normal.
Turn on the fan - similar results, just not as extreme. WTF???

Ski

check the little ground, next to the left headlight by the A/C drier.

400hp944

Will check it out tonight. Thanks

Is this a ground for the lights? What about the fan draw causing similar problems?

Thanks!

Chris Prack

Sounds like you need to measure voltage drop across the ground circuit in your car. Start at the battery and work your way out.

numbskull

I had the same issue a while back, my A/C pump ears that go on the bracket started to crack/snap and there was a slight charging issue nevermind weird ground issues. I replaced the A/C unit and Altenator, shored up the block grounds by the oil separator and it was back to normal. These Ole' cars create lots of weird issues. I still have not found a place that has replacement battery cables, what a pain to cut them and add funky connectors that don't quite fit right.

Tom M'Guinn

I had that issue before I swapped motors. I replaced the battery/alt cables with iceshark version, cleaned all grounds, checked wiring -- never found the cause.

95ONE

Having a bit of a wiring issue myself.

Fist wires are from Fan resistors. Ruined all the way to the fuse box. hence the second picture. I'm going to be busy for a while.

400hp944

How many grounding points are there and where?

Anybody???

reno808

search

lleroyb

Here is a diagram from my 1988 wiring diagram book.

Hope it helps.

Lou

Keithr726

Let us know how those resistor wires go!

95ONE

Nightmare. pulled out the Whole thing a little yesterday and mostly today. Those wires didn't hurt any of the wires near them. But.. I'm using less than half of the wires in the car. Im gutting it out tomorrow.. Every wire.
I have a painless wiring kit in the shop. been there for years for another race car. It's mine now.

400hp944

Thanks for the diagram. I really appreciate it.