j.kenzie@sbcglobal.net

Hi,
I have found my battery dead twice in the last two weeks. I charge it up and it's good to go. Jump post voltage at idle 13.78V. Jump post voltage engine of 12.7V.
I pull my interior lamp fuse #23 and connect an ammeter in series through my ground strap. With everything off, I get a current of 300 ma. I pull all relays with no change. I pull all fuses, with no change. I pulled all the plus A through Z on the CE panel, all with no change.
I am looking for other ideas. Any suggestions?
Thaanks,
Dave

SeanR

Alarm car or no?

j.kenzie@sbcglobal.net

Alarm unit disconnected at Z-plug. Aftermarket alarm disconnected.
Thanks

Landseer

Try to jumper it in addition to plug disconnect.

dr bob

Dave--

Lift the hot post connections and test again. If the drain is still there, you've narrowed it down to alternator, starter area, or ABS system if you have one, but I'm pretty sure that ABS is not an option to search for.

After that you get to go sleuthing for botched aftermarket stereo and car-phone installs sometime in its past.

j.kenzie@sbcglobal.net

Yep. It won't run if not jumpered. That was done 5-6 years ago, no problem until lately.
Thanks, Chris,
Dave

j.kenzie@sbcglobal.net

Will do.
Thanks,
Dave

j.kenzie@sbcglobal.net

I cleaned and reconnected all the hot post connectors and the drain is down to 240 ma. When I remove all the hot post connectors the drain remains at 190 ma. I have read that alternator diode leakage should be 1-2 ma, so I guess that is probably the problem. 50 ma through the car; clock, radio, ecu's etc., and 190 through the alternator/starter. I am voting alternator.
Does this sound right? Oops, I better disconnect the small wires at the + battery post too. Will get back to you.
Thanks,
Dave

j.kenzie@sbcglobal.net

Hi,
OK I disconnected the smaller wire from the + battery terminal. No change in current. At this time I get 300 ma all connected at jump post and battery. With jump post connections all isolated and + battery smaller wire disconnected I get 250 ma. That still leaves about 50 ma for normal drain and 250 ma from the starter/alternator. Tomorrow I will get under the car and isolate the starter. If no change, I will pull the alternator (again). I think this is a plan?
Thanks,
Dave

Ducman82

have you do the "pulling fuses/relay" method yet? one at a time and checking?

dr bob

Sounds like you are doing the right things. It's a little inconvenient to get to the back of the alternator for testing in the car, but easy from the starter end. With jump post wiring lifted, measure the currect between the batte terminal on the starter and the smaller positive lead that goes to the alternator and jump post. Obviously you'll lift that smaller wire to do this... Anyway, with the jump post terminals off and the only connections at the alternator, you'll get a quick confirmation that the alternator is indeed the culprit.

j.kenzie@sbcglobal.net

Thanks, I pulled all fuses, all relays and all CE connectors A through Z.

j.kenzie@sbcglobal.net

Thanks Dr. Bob, will try that too. I think I will be shipping my alternator off for repair Monday. We'll see.
Dave

j.kenzie@sbcglobal.net

BTW Dr. Bob, I am impressed how clever that method is for isolating alternator connections. You must be able to hold many ideas in your head or you just see this stuff all the time. Either way I am most grateful for your expertise. Any time I think about selling my 928, I think about the level of support that exists on this forum. I go on may other forums, but nothing even comes close.
Thanks,
Dave

dr bob

Dave, glad it helped.

A little-known secret.... I spent years teaching a course called "logical probelm solving" for engineers and technicians for a pretty good-size manufacturing company.

This kind of diagnosis starts out with 'eliminate the fast/easy/most-likely stuff, and narrow it down until there's only one available answer'. So start off with the easy stuff, the loads with fuses. That didn't work, so you disconnected all the CE panel connectors. At that point, lifting the jump post terminals completely eliminates the CE panel internal wiring, so the drain had to be somewhere between the battery and the alternator. That left the starter and the alternator. Alternator is easy to isolate at the starter terminal. Divide and conquer...