weird charging problem....solved

Was about to boost son's car..engine not running (on both cars...naturally) I had the booster cables connected to my transport battery (neg on engine block, positive on binding post near power brake) then accidentaly , before connecting to the other car, I accidentally touched both ends..for a fraction of a second, resulting with some sparks of course.
ONce properly connected to son's car, transfer when starting his car was a bit shy of what was needed so I started my engine to charge his battery for a few minutes before a new try...and I saw that my voltage needle stayed in a "no charging" position. Stopped engine as it gave no advantage and well, anyway, the other car eventually started, I disconnected all wires and , before key ON, inched the parking brake pedal down just enough to avoid lighting up the DRL, started TS engine and drove back to son's house, (15 minutes) charging needle staying all the way in the no charge zone..., never stopped the engine then turned towards home...and all of a sudden, the needle went up...normal charging voltage....and no recurrence of the weird problem....till now.
.......no fuse, no thermal relay, no nothing....I have no explanation for that.
www.avigex.ca/xport/chargingstarting.jpg

It may be coincidence. Maybe your alternator is dying. I may have misread your post but the "good car battery" gets connected directly, not running through eng frame. The "bad car battery" does go through the frame. And to prevent that in the future. Always connect both reds/positive first.

Found...unrelated to spark or boosting..ignition key failed contacts...occasional then.
I have been able to duplicate the event by jiggling with the key. Run contact and other accessories contacts are fed separately by the ignition switch (3 contacts).
www.avigex.ca/xport/ignitionkey.jpg
and by the way, as with all cars. negative IS connected to engine block..otherwise the starter would not ..start. Yes there are separate ground wires fed to several other components, but the engine block is always negative....the starter ..and several other components..have NO other ground feed.
www.avigex.ca/xport/ground.jpg

and by the way, as with all cars. negative IS connected to engine block..otherwise the starter would not ..start. Yes there are separate ground wires fed to several other components, but the engine block is always negative....the starter ..and several other components..have NO other ground feed.
www.avigex.ca/xport/ground.jpg

Eng block/frame connected only on the dead car side, not the boost car side.

Your post made it sound that on the boost car you connected negative to the frame.

LMP, did you ever sort the problem out, did you change out the ignition switch? Been chasing a no charge situation on my TS for a week now, alternator bench tests fine, but will not work in van. Finally installed a self exciting regulator to bypass wiring in van, works great. Wish I had done that in first place! Everything else connected to ignition switch works fine, just wouldn't charge.
Jeff

LMP, did you ever sort the problem out, did you change out the ignition switch? .....
Jeff

It turns out the alternator itself is the culprit. I'm just taking it out from the car. I had tested the feed to the regulator and it was OK. It kept working ..or stopping working from time to time but eventually completely quit. I think the regulator is shot. I will report on progress.
I'm still keeping it alive but signs of its age do surface regularly. At this time, I have a rear wheel hub shot, very high fuel burn possibly due to either the O2 sensor itself or its wiring near the computer plug, lots of body cracking due to underbody corrosion.....rear shocks, exhaust manifold donut.....and all fluid lines more or less suspect to blowing out ....I do not dare to drive it very far from home now....so sorry....
My preferred option is an Equinox.....

You might want to look at reliability issues before you go with an Equinox.

You might want to look at reliability issues before you go with an Equinox.
I take notice. Thanks....
About alternator: really solved now. Problem was occasional and the charge would simply come back after I had changed something, leading to false interpretation.

The voltage regulator was shot. I bought it locally. I could have it at RockAUto at a saving of 15C$ ...well in fact, with shipping, it would have been the same, but the handling/shipping would have covered a few more small items I had in mind for almost the same shipping fee. ANyway, I have it NOW, instead of waiting a week or 10 days..RockAUto is generally fast....This is the second time I replace it (last time about 12 years ago).

THis 105Amps alternator is said as "unserviceable" in the GM book...contrary to the 140A version. THis is because the stator wires are soldered to the diode pack, while the 140A version uses 3 little screws for the same purpose and can be separated from the diode pack easily. But if you are handy with a soldering gun, no problem at all once the stator wires are separated from the diode pack. By the way, the diode pack is not original: the original had failed about 15 years ago, a real POS but the Bosch replacement I have is a real sturdy unit.

Here are a few pîctures of the dismantled unit and partly reconstructed.

http://www.avigex.ca/xport/alt1.JPG
http://www.avigex.ca/xport/alt2.JPG
http://www.avigex.ca/xport/alt3.JPG

That's a heck of a helpful post LMP!! Great job with the images and breakdown. That will surely help future troubleshooters!! :thumbsup: :thumbsup:

In my casI was wondering if the e the symptoms were of an alternator failure-gauge down, turn signals slow etc, and was putting out just over 13V no load, dropping even more loaded. Everything internally checked out, leaving just the voltage regulator as the prime suspect. New one fitted, would not charge. Took alt back off, bench tested not working. New Regulator fitted under warranty, bench tested ok., but still would not function in van. Followed logic tree in manual, says supposed to have B+ at L terminal once engine starts, only had 10.5 V. Wiring in circuit 225 checked out, even did the wiggle test on it, opened up connector 110, all looking good, yet alternator would not function. Got to stage in troubleshooting where it says change PCM (yikes!) still no change. Took alt to another test facility in town, where he was able to get alternator to function by placing a 194 indicator bulb in series from alternator output (12V) to L terminal in voltage regulator. Clearly the PCM is not turning on the alternator. I was wondering if problem with ignition feed( switch) could have caused the problem, altho no other switched circuit appears to be affected. LMP, have you had any other issues with your ignition switch?After a week, and a lot of money thrown at this, gave up, and put self exciting regulator on, bypassing the whole PCM circuit, and all works fine now

In my casI was wondering if the e the symptoms were of an alternator failure-gauge down, turn signals slow etc, and was putting out just over 13V no load, ....

Yeah..turn signal slow = low voltage.
Remember I had a diode failure years ago. IT was still delivering voltage at no load, but would not deliver a lot of amperes.
In my case, there is no feed to the alternator through the ECM, only straight wiring. NOt sure where your 10.5 volt comes from, but the very small wire gauge in my car causes system voltage drop too even with only the blower fan lower speed....
ALso..I have bypassed the ignition switch ..with an accessory switch driving a relay that feeds all the engine utilities usually fed by the ignition switch...; the ignition switch is so hard to reach (low on the steering column) that I just forgot about it. So I have to turn my accessory switch ON then start normally with the ignition key. TUrning the ignition key OFF will not kill the engine...the new switch must be turned OFF too.....weird, but....I can live with it.