Jetdriver69

Well my alternator has checked good. So I guess its back to chasing wires. I will follow Dr Bob's suggestions. Hopefully it just a loose blade connector in Z or O bundle that I missed. A in the 14 pin looks ok.

anakilat

I was having a similar problem this week with my 80. I had the battery checked in the car and it was good but the alternator wasn't charging. I removed the alternator and took it to be tested - it was also good. I put it back together last nite and at first start and idle it still didn't charge (11.8v). I decided to take it around the block. When I got back it read 14v. When the electric fan kicked in it dropped to 13.5v. The only "problem" is that the fan in front of the radiator is cycling on and off (with temperature) and it never worked before. The car also now does a very nice high idle when cold - never did that before either. The engine is quieter and smoother at normal idle as well. I assumed a bad connection but I didn't find anything that looked even a little bad when I took it apart. I think I'm going to have to get under it while it's running and wiggle the wires near the alternator to see if voltage drops back to battery voltage again.

Alan

Unfortunately this means very little...

On alternators that have been run for a while (e.g. not spanking new) the rotor often picks up a little residual magnetism - this can then be enough at high RPM to create enough of a field to initiate generation that then sustains itself - however - this is only a fortunate factor - it does not mean the alternator is working properly - though it usually means its capable of working correctly. It usually indicates a faulty exciter circuit in the car, which needs attention. best starting point is to see if the charge light ever come on during the bulb test - and/or evaluate if you even get a bulb test when you first turn the ignition on.

Alan

Alan

Just monitor the voltage on the exciter connections:

It should be ~2-3v with ignition on engine stopped. Should be >12v when running

What do you find ?

Alan

anakilat

Thanks for that tip Alan. Since I currently don't have a gauge pod I can't see a bulb test. Could you tell me where I test the exciter voltage? Is it the rear of the alternator (blue wire) on D connection? Or hopefully somewhere up top?
-- oops -- I just re-read the earlier post by Dr Bob. I'll try that and get back to you

anakilat

WOW! I'm an idiot. It never occurred to me that the exciter circuit would be part of the gauge pod that has been out of the car for a year waiting for a replacement. I used a GPS as a temporary speedo when I took it out for it's weekly run. I always disconnected the battery for theft prevention when I parked it. My son has been using the car as his daily driver for a couple of months while his 944 is torn down. I guess the alternator didn't run long enough to recharge the battery when he started night shift last week and used the headlights every day. I think I'm pretty impressed that it ran it a year like that.

Mrmerlin

adding in tidbits like, I dont have the pod connected, could this cause a problem with my charging system
might be useful info for troubleshooters to know before they give a best guess scenario

Jetdriver69

Ok fixed the charging issue. Thanks for all the inputs. A pin/on the 14 was a little loose, so tighten that up a bit. Z connector was removed, all wires pulled out and tightened up and replaced with new female connectors. A few blades on the Z terminal had split in two when I replaced the multiline connectors after I cleaned up the fuse panel. So perhaps good contact was not being made on the exciter circuit. Lesson learned for anyone doing a fuse panel refresh, make very sure the blades don't split when replacing the bottom multiline connectors. Now I got 13.5 volts and maybe 13.1 with the AC on. Sure it was a pain tracking down an essentially self induced problem, but now I know all circuits are good, no shorts, no broken lines, no more chewed wires and all my grounds are clean. I just got my package from Leatherique, so now on to the interior. On a side note, I had a freon leak through my expansion valve after replacing the compressor and dryer. The compressor was only 3 years old but sat unused the whole time and the seals dried up. Now all that was new and tight, the increased head pressure caused the old expansion valve to leak. Come to find out, the AC "expert" who worked on the car for the PO did not change the O rings in the expansion valve when converting to R134. Now I essentially have a new AC system too. I guess it could be worse, I could be buying Ferrari parts like my neighbor.