Starter fell off now battery drains drastically - PeachParts Mercedes-Benz Forum

renman · #1 09-05-2007, 03:11 PM

So for awhile, my daughters car "PUFF" had been getting harder and harder to start. Finally one day I was turning a corner and I heard a clunk from under the hood. I didn't think anything of it until I got home and attempted to leave in the car a few minutes later. Yes the starter was hanging by the cables. Over the next few days I had the starter tested at AZ confirming the starter was okay to use, cleaned up the cables and installed the starter, only this time without the support bracket which I presume is lying out on the highway somewhere. In last two weeks I have also replaced all of the glow plugs, and the car starts fine... except the battery is draining quickly and has been a serious problem resulting in numerous chargings and some required jumps away from the house. At present this car is not being used for fear she will be stranded somewhere.... again.

Here is what I know and don't know after my trip to the battery/alternator shop, Auto Zone and my screwing around with the car this morning. In chronological order.
1. The battery was showing 12.47 volts when I left to go to AZ. yesterday.and by the time I got there, my DMM was reading 12.01 volts @ the cigar lighter.
2. The AZ guy tested the battery on and off the car and said it was fine. He could not confirm that the alternator was working properly for some reason but by the time I left there my volt meter read 11.85 volts.
3. Went to Sears, turned off car, and bought the venerable $29.95 DMM to replace the junk I was using, (amp side wasn't showing any reading) and then stopped at alternator/battery shop.
4. The guy at the battery shop test battery, alternator under load, and diodes and says except for the battery not fully charged everything is okay.
5. I drive home. Total time in car probably 90 minutes. I did not have any appliances on whatsover. When I got home the voltmeter read 11.31volts and the car wouldn't start after turning it off.
6. Charged the battery for 19 hours with battery cable off. Ordered a digital ammeter based on forum recommendations. Reading this morning using new DMM from Sears across the battery was 13.47 volts.
TODAY:
Using the new DMM set on DC volts the battery read 13.13 volts at 1:00PM. Touching the negative battery post and the negative cable, with the leads produced an initial reading of -0.208ma
A. If I remove the starter cable from the terminal block by the battery the ma reading goes to -0-
B. Attached to the positive battery terminal is the power source for the AC compressor. This wire runs to a relay mounted on the drivers side fender. If I have the starter cable removed above and touch the AC power lead to the battery the DMM reads -0.208ma. The power source to the AC is unfused by the way and doesn't go through the fuse block.
C. Using the DMM and pulling the fuses did not produce any change in loss.

What is going on? Is my starter bad, the starter cables from the terminal bad, and how is the power wire from the positive battery cable running to the relay, related to drain?

As I am typing this I received a digital low current ac/dc clamp meter with probes by Ups. I will go back out later and see if I can get more specific. Am I on the right track?

Really confused.

pj67coll · #2 09-05-2007, 03:46 PM

First off which car is "Puff"? The 84 123? You say the starter actually "fell off" the car? If so is it possible that if there are cables or wires from the starter to the alternator have been damaged. Maybe disconnected inside the plug where they attach to the alternator thus causing the alternator to fail to charge the battery properly? My electrical knowledge is slim to none so so beware before acting on my advice.

- Peter.

renman · #3 09-05-2007, 04:10 PM

Sorry I thought everyone knew what my daughter named her car.

"Puff" is the 1984 300D

As a P.S. the problem with charging was happening to an extent before the starter fell, but I thought that the problem was gone after switching out batteries and having a full charge on system to begin with. It has been more of an issue since the cooling.AC season. I don't remember having a problem until late spring when we started using the AC. The battery is a 850CCA unit.

blindwolf · #4 09-05-2007, 04:11 PM

I would remove the cables (one at a time) and put the ohm meter to them. That way you will know that :
1. There is no internal damage to the cable/wire.
2. Both ends of each cable/wire are tightly connected and clean (when you put them
back on).

renman · #5 09-05-2007, 04:22 PM

Do you mean I should use the ohm settings on my DMM to test the cables from the starter to the relay block?

blindwolf · #6 09-05-2007, 04:53 PM

Yes, diconnect the wires/cables ( if possible) and put a lead on each end and use your ohm function, this will give you some idea of the wires condition in the sheath.

Cervan · #7 09-05-2007, 05:34 PM

start you engine, turn on the radio and headlights (headlights on high beams) and then remove one of the battery terminals, check the voltage on the terminals, check the idiot light on the instrament pannel, or if everything goes dead.

renman · #8 09-05-2007, 06:25 PM

Cervan Said: start you engine, turn on the radio and headlights (headlights on high beams) and then remove one of the battery terminals, check the voltage on the terminals, check the idiot light on the instrament pannel, or if everything goes dead.

I thought I had read on the forum that that this was a sure way to Fry your diodes in the alternator.??
Here it is BY Roy Hunter
Quote:
Originally Posted by BigBenzno
I too thought it was a bad alternator and removed it to have it tested 'round the corner at NAPA and everything tested O.K. on their new computer thats whats confusing me. I can run the car with no (neg.) cable hooked up but there is no electrics on the car... touched the pos. to terminal and the neg. to ground... did I mess that up too?

You burnt the regulator.
"NEVER", disconnect battery cables with engine running, it blows the voltage regulator.
__________________
whunter

According to Brian Carlton:
Anything over 60ma (about 1/3 of full scale) is not acceptable.

I did unplug the alternator and the 0.203ma didn't change.

Cervan · #9 09-05-2007, 07:18 PM

This i did not know, but it haddnt occured to me that this is what would have happened.I am sorry, do as the others state then.

renman · #10 09-05-2007, 08:18 PM

No problem Cervan. I'm learning also.

Chocolate Benz · #11 09-05-2007, 09:05 PM

Renman,

What about the chance that while the starter was dangling from the cables that the terminal on the starter got pulled out of line enough to create a short. One of your test instruments should tell you if the circuit is good.

oldiesel · #12 09-05-2007, 09:09 PM

disconnecting the battery cable to test the alternator is one of those old things that just wont die.That was considered a valid test when cars had GENERATORS,nearly 50 years ago.Alternators are a totally different thing,if you disconnect the battery cable with the engine running you really risk destroying the rectifier diodes,you might get away with it at idle but if you rev the engine up you can count on a dead alternator! Generators did not have diodes or any other electronic components. My $.02 Don

barry123400 · #13 09-05-2007, 10:32 PM

With the engine running read on low volts scale between the valve cover and the negative battery terminal. If you get a voltage the strap between the engine and chassis is offering too much resistance. Also could be poor connection at body from negative terminal. Or perhaps the problem has worsened because of the starter getting loose in the area of the engine ground strap. Regardless of the garages tests you are not charging your battery I think.
Also prove it by reading across batttery terminals with engine running. If voltage is not above 13v you know you are not actually charging at idle. if these things check out okay then start looking for the drain. Basics first unless you have already checked them out yourself.

renman · #14 09-05-2007, 10:47 PM

Thanks Barry. I think I will check the wiring to the starter the grounding strap and finally the Alternator one other way suggested by Deerefanatic in an e-mail conversation. When I parked the car yesterday the volts across the battery where 11.31 if I remember correctly. Ya the wiring could have been abused as the starter was coming loose. What a pain.

deerefanatic · #15 09-05-2007, 11:01 PM

Also, invest in a REALLY GOOD battery charger, one of those digital ones would be best. Take battery completely out of car, put on charger with a slow (less than 6 amps) charge current for 24hrs.... That will make SURE your battery is completely charged. Troubleshooting a charging system with a partially discharged battery is a regular pandora's box in and of itself. don't ask me how I know.....