does my 1987 560sl have a seat sensor for an airbag? - Page 2 - PeachParts Mercedes-Benz Forum

kimmy · #1 03-08-2004, 09:56 AM

Quote:

Originally posted by MikeTangas
OK, you'll want to put the red lead in the hole marked + and the black lead in the -. Set the dial to DCV to a number higher than 12, probably should be a setting for 20+/- DCV, that is the one you'll want. Before starting the car put the + lead on the + battery post and the - lead on the _ battery post, what is your reading? Should be 12.5vDC or so. Next start the car and repeat the test, what is the reading now? You should be seeing 13.8vDC or so.

Report back with your findings.

Here are your results, the first read was 10.23 (FYI the car had not been started in over a month)and after the jump to start it, the read was 13.97. I'll be waiting for my next instructions.
thanks again so much for seeing me through this.
kimm

kimmy · #2 03-08-2004, 10:14 AM

Quote:

Originally posted by blackmercedes
I can find some old posts where a mechanic tested the alternator and it turned out to be bad.

I think we have some misdiagnosis here. It's the clock? Try pulling the fuse for the instrument cluster and seeing if that stops the key-off drain. That's a pretty simple thing to check and your mechanic's wish to just start replaing parts willy-nilly sets off alarms with me.

Getting back to the problem. The obvious needs to be checked: The alternator and voltage regulator. Too much voltage could be frying the battery. Many MB owners have been stumped by an alternator with a lower output that is still charging to some degree. Mechanic puts meter on posts, finds output, and declares charging system okay.

Once the charging problem is sorted, you may have to replace the battery as depp discharging can wreck even a farily new battery...

I returned to the battery store and had them check the battery and they told me it was good.

blackmercedes · #3 03-08-2004, 10:39 AM

You need to stop starting the car only once a month. We have no way to tell what's going on if the car has sat for that long.

Take the car for a drive. A fairly long drive. Let it sit overnight and see if the dead battery problem persists. If so, then you may have a key-off drain. This takes some patience to track down. You'll have to begin pulling fuses to locate the culprit circuit. Also, while the car is parked, pop the hood and listen for the ABS pump or other devices that might be running.

Also, once this is sorted out, start driving the car. 60,000 miles for that age of car is not good. Mercedes' thrive on being driven and you're not doing the car any favours by letting it sit.

kimmy · #4 03-09-2004, 12:06 PM

Quote:

Originally posted by blackmercedes
You need to stop starting the car only once a month. We have no way to tell what's going on if the car has sat for that long.

Take the car for a drive. A fairly long drive. Let it sit overnight and see if the dead battery problem persists. If so, then you may have a key-off drain. This takes some patience to track down. You'll have to begin pulling fuses to locate the culprit circuit. Also, while the car is parked, pop the hood and listen for the ABS pump or other devices that might be running.

Also, once this is sorted out, start driving the car. 60,000 miles for that age of car is not good. Mercedes' thrive on being driven and you're not doing the car any favours by letting it sit.

Golly gosh, I feel sooo bad. I feel like I need to go tell her how sorry I am. I have taken her for a very long drive and come home and park her and 15min later she's DEAD DEAD DEAD. I will try what you said and listen under the hood. I would drive her more but everytime I try to put my kids in the trunk they get away. I would promise to do better with putting miles on her, it would help if I know that when I got to where I was going I knew that I could come back. Anything I can try to figure this out?
Kimmy

MikeTangas · #5 03-09-2004, 12:27 PM

Something is wrong here, if your alternator is putting out 13.9vDC at idle, after a long drive the battery should be charged enough to not be dead, dead, dead 15 minutes after returning.

I would try getting it started up again and rechecking the output, see what you are getting at idle and then watch the meter and see what happens as you raise the RPMs, to maybe 2K. Output should remain basically static, it might go up a very little but should hold about the same. Another way a regulator can go bad is by overcharging. Let us know if the output increases and what it increases to as the revs come up

blackmercedes · #6 03-09-2004, 12:41 PM

Quote:

Originally posted by MikeTangas
Something is wrong here, if your alternator is putting out 13.9vDC at idle, after a long drive the battery should be charged enough to not be dead, dead, dead 15 minutes after returning.

This is not a key-off drain. However, if the alternator is shot, the car won't keep running either. Eventually the reserve power of the battery will be gone and the car will die.

There is a charging system fault somewhere. What parts are there? Alternator, regulator and battery. Anyone think of anything else in the "circuit" that could be failing?

Is the voltage regulator integrated into the alternator on this one? I'd be tempted to replace both, but I'm loathe to throw parts at a problem without having the proper diagnosis.

And to the mileage and driving the car, I meant once this problem is sorted out, you should drive the car more...

kimmy · #7 03-09-2004, 12:50 PM

Quote:

Originally posted by blackmercedes
This is not a key-off drain. However, if the alternator is shot, the car won't keep running either. Eventually the reserve power of the battery will be gone and the car will die.

There is a charging system fault somewhere. What parts are there? Alternator, regulator and battery. Anyone think of anything else in the "circuit" that could be failing?

Is the voltage regulator integrated into the alternator on this one? I'd be tempted to replace both, but I'm loathe to throw parts at a problem without having the proper diagnosis.

And to the mileage and driving the car, I meant once this problem is sorted out, you should drive the car more...

Ok, here is the deal, I was going from memory when I said that I drove her a good long drive then parked and 15 min. she was dead. I will go take her out now and report back exactly how long it takes for her to go dead. I should have been more specific. And ounce it is started I'll do the test that again and see what the read out is at a higher rpm. I'll get back to ya. And thanks soooo much for stickin this one out with me. I thank you guys enough. Don't give up on me.!!! I'm goin for the drive now.

dmorrison · #8 03-09-2004, 12:51 PM

Quote:

Originally posted by kimmy
I try to put my kids in the trunk they get away.
Kimmy

??????????????

This sounds strainge

Dave

The "kids get away"??

#9 03-09-2004, 12:53 PM

I'm thinking battery. Start the car and take it for a long drive. Then turn the car off and disconnect the positive terminal from the battery and let the car sit over night. Without reconnecting the battery in the morning - check the voltage on the battery - if it is below 12 volts - you have a bad cell - if it is still below 11 volts - you have 2 bad cells. If it is about 12.56 volts or higher - then you have something draining the battery. Let us know
Morris

MikeTangas · #10 03-09-2004, 01:30 PM

It could be a double whammy, a bad battery and a bad voltage regulator.

If the regulator was bad and overcharging the battery it could cook the battery and now you've got a bad battery to boot.

John, the voltage regulator (or brush pack) is attached to the back side of the alternator with two screws. Easy to replace, but a tight fit in the V-8 bay.

Dave, doesn't everyone keep their children in the trunk??? Harder to keep them in there now since the newer vehicles have those "escape" pulls on the inside. Must be her SL has been retrofitted.

MikeTangas · #11 03-09-2004, 01:36 PM

Also, double check the water level on each cell.

kimmy · #12 03-09-2004, 06:14 PM

Quote:

Originally posted by MikeTangas
Also, double check the water level on each cell.

OK Here are the results. drum roll please....I went to the car and tested the battery before I started it and it read, 10.96, I started it (with a jump) and tested again and it read, 13.91. Then I brought it up to 2000 rpm and at 2k rpm it read 13.92. I drove it for two hours. However I left the house and drove 7 miles to the shop becauce I noticed that it had spilled some oil on my floor, and wanted them to look at it real quick. They shut it off before I could stop them. It was off for 15 min. and it started up again YEA!! (They said that I have a leak at the oil sensor, going back Thursday so they can spray some new kinda thing on it that will keep it from leaking. Only about 60.00, but has to sit 8 hours to set. Has anyone heard about this ?) Any way I continued to drive drive drive. ( I love the thumbs up I get on such a cold winter like day) I made a few stops, but not longer than a few minutes each. Got home tested again once I shut it off and it read12.33. Now one of you says to park and wait till morning and see what the read is in the morning and the other says to disconnect the + pole and wait till morning, test before I hook back up and again after. What one should I do.? And by the way the battery is closed cell so not sure how to check water, and on another note, when I pulled into the driveway today I honked at my dog and the horn sounded a little sickly, could this be related??? Just thought I should throw everything out there, ya never know. Or I should say I DON"T HAVE A CLUE.
Kimm
Kimm

blackmercedes · #13 03-09-2004, 06:45 PM

You need a helper. With the car running and the headlights on, sit at idle and check the intensity of the lights. Rev the engine to 2500 or so and see if the lights brighten at all. If not, then you have a charging problem as the increased current from the alternator once the threshold rpm is met should juice up the lights a bit.

Static voltage on the battery won't tell us much, not the way load testing will. But, there is a quick way to tell if you have a key-off drain, and that is to disconnect the battery and leave the car overnight and recheck the voltage. If you undo the positive lead, please be VERY careful not to allow your wrench to touch ground while working on the positive terminal.

I still think it's a charging problem. Why?

We had the same problem with our 1990 190E and the idiot dealer kept chasing a key-off drain. After three full months of mucking about, the alternator finally gave out. It was slowly fading away and charging intermittently. The dealer would test it and it would read 13.7 evey time, but we had dead battery problems. Now, to the credit of the dealer, the alternator tested okay when they had it. However (I had sold the car to Dad at this point) they insisted that it was the power antenna draining and charged him $500 for a new unit. Cripes. Anyway, one day the alternator finally calved. I put in a new brush set and it's been fine since. $60...

kimmy · #14 03-09-2004, 06:50 PM

Quote:

Originally posted by blackmercedes
You need a helper. With the car running and the headlights on, sit at idle and check the intensity of the lights. Rev the engine to 2500 or so and see if the lights brighten at all. If not, then you have a charging problem as the increased current from the alternator once the threshold rpm is met should juice up the lights a bit.

Static voltage on the battery won't tell us much, not the way load testing will. But, there is a quick way to tell if you have a key-off drain, and that is to disconnect the battery and leave the car overnight and recheck the voltage. If you undo the positive lead, please be VERY careful not to allow your wrench to touch ground while working on the positive terminal.

I still think it's a charging problem. Why?

We had the same problem with our 1990 190E and the idiot dealer kept chasing a key-off drain. After three full months of mucking about, the alternator finally gave out. It was slowly fading away and charging intermittently. The dealer would test it and it would read 13.7 evey time, but we had dead battery problems. Now, to the credit of the dealer, the alternator tested okay when they had it. However (I had sold the car to Dad at this point) they insisted that it was the power antenna draining and charged him $500 for a new unit. Cripes. Anyway, one day the alternator finally calved. I put in a new brush set and it's been fine since. $60...

I'll be back in a few, I'll go do your test.

kimmy · #15 03-09-2004, 07:00 PM

Quote:

Originally posted by kimmy
I'll be back in a few, I'll go do your test.

Well I didn't have a helper but it's dark and I put the lights on the garage door, did as you asked and nothing, BUT, it did start all on its own though, doesn't that count for something? I shut it off at 5:45 and it is now 6:59. What should I do now?
Kimm