1979-1993 & 94 Conv [Subscribe to Daily Digest] |
 | [Main C900 Bulletin Board | BBFAQ |
Prev by Date | Next by Date | Post Followup ]
Member Login / Signup - Members see fewer ads. - Latest Member Gallery Photos
Exception notable Posted by Arabiflora [Email]  (#1129) [Profile/Gallery]
(more from Arabiflora) on Tue, 27 Feb 2007 22:24:44
In Reply to: Re: IT IS DONE, aalto, Mon, 26 Feb 2007 09:54:20 Members do not see ads below this line. - Help Keep This Site Online - Signup |
I agree with your premise that MANY, er, SOME battery shops or alt rebuild outfits will inappropriately jump to the conclusion of worst case scenario: Dead battery or trashed alternator. However, as our c900s age (and we along with them), there arise certain exceptional cases that should be considered. In my case ('88 900S, 355k mi) I had persistent charging problems such that alt light was on at low revs, went out at high-- typical signs of bad ground, right?
Checked and R&R'd all grounds, no cure.
Bad VR? Inspected, plenty of brushes left but suspecting diode failure, replaced. Better (alt light went off at lower rpms), but no cure.
Lacking any other reasonable suspect, I pulled the alt and took it to a rebuild shop. It tested dead on their diagnostics, upon further inspection it was revealed that the slip rings (they provide electrical connection between brushes and commutator) were gone. $75 or so for rebuild, using my new VR, and problem was solved.
My suggestions for triage on charging issues (light goes out at high rpm):
0. (I thought of this one later): Check belt presence/tension to alternator
1. Swap battery for known good.
2. If problem persists after >100 miles under electrical load, it isn't your battery-- you just drained another one. Check the grounding points, R&R as nec (it can't hurt)
3. If symptoms remain as above, add an additional ground wire from alt to block.
4. If symptoms remain as above, inspect brushes on VR. Many posts on the board will suggest minimum length that indicates good or bad condition, and many also suggest cheap ways to refurbish if they are excessively worn.
5. If all else fails, pull the alternator and have it bench-tested by a shop that does that sort of thing.
These are just my rec's, certainly worth what you've paid for reading them, and I'll admit that I may be among the least among Saab diagnosticians generally. Nonetheless, this list comes from personal experience, painfully gained after many prior hours spent dicking around with voltage tests of one sort or another, and has the virtue of working through the troubleshooting process in order of increasing cost.
, Sun, 25 Feb 2007 04:38:31, Sun, 25 Feb 2007 14:38:45
, Sun, 25 Feb 2007 19:44:34, Tue, 27 Feb 2007 22:24:44 <-- Viewing This Message, Sun, 25 Feb 2007 09:57:51, Sun, 25 Feb 2007 04:48:32, Sun, 25 Feb 2007 05:14:11, Sun, 25 Feb 2007 09:53:06
No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.
 |
 |
 |
 |
 |
