New Starter not working! Electrical woes.. - Page 2 - PeachParts Mercedes-Benz Forum

BillGrissom · #16 10-13-2014, 03:49 PM

Some German terms have interesting English translations (British?). "Warning monitor" sounds like a "buzzer". I unplugged the factory alarm box since it enjoyed going off for no reason. "Switch-over" usually means "on-off switch". The "valve" in it sounds wrong since I suspect a totally electric device. It might refer to the "seat belt pre-tensioner", which is behind the B-pillar cover at the bottom and serves to tighten the seat-belt as acceleration sensors indicate an accident.

I vaguely recall a similar current draw on a similar fuse. I no longer have the factory radio installed, in either 300D. Too bad the 1985's prior owner spent >$100 to have a few LED segments in the radio display fixed. Anyway, it would take a long time for a 1.3 A draw to run down your battery. Shouldn't it have ~1000 A-hr capacity? Something else may be going on. Do you know that 3 dash bulbs supply "boot-up field current" to the Motorola-style alternator? (D+ terminal, same on GM cars then) Without that, it won't output current. The "battery" bulb is the main one. Your manual says to immediately drive to the dealer if that bulb doesn't come on with the key. Perhaps dealers charged $100 to change a light bulb. They really drag the rich owners through the trough. Us bottom-feeders who own these cars now are more resourceful.

Greasy83TD · #17 10-13-2014, 04:11 PM

Is it possible the bulb is partially out? It still glows, but maybe it could be the culprit for some of these problems if not seated correctly. I'll switch w/ the bulb from my parts car and see what happens while I scratch my head over this starter motor.

leathermang · #18 10-13-2014, 04:17 PM

Some radios need to be kept connected to retain ' pilot operated' settings in its memory.... so a car can have some tiny drain even with everything off.... but that should not be enough to drain any self respecting battery.

Greasy83TD · #19 10-13-2014, 06:29 PM

Replaced dash batt light with known good bulb. No change.

Back to starter issues...

Batt @ +12.5V
Starter terminal junction +12.2V
I measure +11.3v at solenoid post when an assistant turns key to start, but I don't hear a click. It must be activating partially, because I measured the same 11.3V on the starter post bolt when key in start pos.

I guess the wiring is going bad. Time for a trip to pick up some heavy gauge wiring and make my own harness for the starter.

It seems strange though that +11.3V is too low to even make solenoid fully click... It cant be ONLY the wiring..

Greasy83TD · #20 10-14-2014, 02:04 PM

So here's some resolution. After removing the starter for the 2nd time, I discovered the +12V post on the solenoid was loose on the reman starter. The car now cranks with pliers jumping the terminal block, but not with key anymore. I guess ignition switch went bad while I was working everything else out.

leathermang · #21 10-14-2014, 04:34 PM

Since you are bypassing safety switches..like the neutral start switch..
Be Sure YOUR CAR IS IN NEUTRAL OR ParK....

We have had two old long time farmers killed by their diesel tractors ... run over by them ....they were brothers.....and the two accidents were years apart.... one was a County Commissioner in Travis County for years... a moment of inattention... is all it takes....

Greasy83TD · #22 10-15-2014, 11:29 AM

I'm about ready to have this car run me over.

Jumperd NSS to bypass.
New Ignition switch.
New wiring harness and ground straps.
Battery light still does not come on. Other self checks work fine now.
Plugged in an old, but working alternator and grounded it to batt. Same result, no batt light, no crank.

When I turn the key, I see +12V at the solenoid, and at the starter post, but I dont hear a click.

Ive pulled the starter 3 times now and it works fine outside the car everytime.

I think my car is haunted.

Anything else worth trying before I sink more $$$ into another reman starter and solenoid?

barry12345 · #23 10-15-2014, 01:12 PM

Quote:

Originally Posted by Greasy83TD

I'm about ready to have this car run me over.

Jumperd NSS to bypass.
New Ignition switch.
New wiring harness and ground straps.
Battery light still does not come on. Other self checks work fine now.
Plugged in an old, but working alternator and grounded it to batt. Same result, no batt light, no crank.

When I turn the key, I see +12V at the solenoid, and at the starter post, but I dont hear a click.

Ive pulled the starter 3 times now and it works fine outside the car everytime.

I think my car is haunted.

Anything else worth trying before I sink more $$$ into another reman starter and solenoid?

Since you bridged the two terminals on the starter turned the grounds and positive feed and starter motor and solenoid seem okay. Unless it was a temporary fluke. Still if the voltage on the solenoid terminal is remaining at twelve volts with the key on start the solenoid is not drawing current or very little. In my opinion it should fall off a volt or so below the battery voltage. You want a properly charged up good battery before doing much in this area.

Your voltage may be marginal for the solenoid to pull enough current down the trigger line to operate the solenoid. A lot of German cars seemed to provide marginal wire size for the solenoid loading current over the years. Too much voltage drop if every connection in that circuit is really good.

Things have to be in fairly good shape to trigger them. A battery at twelve volts may not be enough. I consider that a pretty discharged battery. Twelve point five or a little higher is usually fully charged or at least enough. Twelve volts is not.

I also think you have alternator issues and this may have put you down this road. Get the battery voltage up to where it should be and the starter circuit may be easier to deal with. Then some attention to the alternator can be done after that. All the members try to help others out from time to time.

Greasy83TD · #24 10-15-2014, 01:28 PM

Thanks for the response. This feels like a simple problem... but its making me a little crazy.

Ohm reading from solenoid signal to GND key off reads ~6ohm

heavy jumper cable from BATT GND to a variety of engine grounds, including the starter body itself yields no results.

I connected the jumper cables directly from + and - on BATT to the bottom post of solenoid (starter +) and body of starter, respectively. Still nothing but fat sparks at the connections and not a budge from the starter.

Jumping the solenoid posts with a screwdriver with a jumper to BATT GND yields the same results, only fat sparks no action.

Once the rain lets up I'm going to pull the starter again and either try to return it, or pull it apart myself. Last time I pulled the starter, it would work fine out of the car, and it would work in the car only once, then never again, no matter what tricks I attempted to jump it. I like the theory that something is loose in there.

leathermang · #25 10-15-2014, 01:32 PM

I think the starter needs to be checked on something called a ' growler'....

barry12345 · #26 10-15-2014, 02:04 PM

[QUOTE=Greasy83TD;3396888]Thanks for the response. This feels like a simple problem... but its making me a little crazy.

Ohm reading from solenoid signal to GND key off reads ~6ohm

heavy jumper cable from BATT GND to a variety of engine grounds, including the starter body itself yields no results.

I connected the jumper cables directly from + and - on BATT to the bottom post of solenoid (starter +) and body of starter, respectively. Still nothing but fat sparks at the connections and not a budge from the starter.

Jumping the solenoid posts with a screwdriver with a jumper to BATT GND yields the same results, only fat sparks no action.

Intermittent motor short unless the battery is very,very low is indicated. Non closing solenoid contacts would not cause the sparks. Although some form of short in the solenoid when activated might. It is almost certain the starter assembly is bad other than if the battery is way undercharged. I think the booster cables in parallel with the original main feeder wire would eliminate the factor of too much resistance existing in the positive cable. Same with the grounds .

airfoill · #27 10-15-2014, 02:16 PM

I had a similar occurance where the starter switch sometimes worked and sometimes it didn't. It turned out that the plug at the neutral safety switch attached to the transmission wasn't fully plugged in at a couple of slots. somtimes it would make contact and sometimes it wouldn't. Make sure the plug in plugged in.

Another different issue with my electrical system at another time was the voltage regulator was worn out when I noticed faint light on the dash lights...replaced with new voltage regulator and everything came back to normal.

Greasy83TD · #28 10-15-2014, 05:19 PM

Just got back from my local auto electric shop with the starter and alternator.

Starter tester good at the shop, but they seemed unwilling or unable to test it with a growler after it had worked fine there.

Alternator tested bad, they said it was internally shorted and they are exchanging it under warranty.

When I get the chance, I'm going to test the motor grounded and attached to the wiring harness, but not installed to the bell housing and see what comes of that.

leathermang · #29 10-15-2014, 05:23 PM

when they would not test it... that is when you were supposed to growl.

Greasy83TD · #30 10-17-2014, 02:31 PM

Update:

After finally getting the starter apart and growler tested at another elec. shop I found, it comes back fine. I wired the starter up on top of the engine bay to test it. As expected, it spun once, then nothing on the second try. Shorted.

I then disconnected my alternator, and hand spun the starter backwards with my fingers a few turns. Spins every time now.

So whenever I have an alternator connected, the starter only works on the first try. I repeated this a few times with the one alternator I have left. I guess last few times I had the starter in, the alt was still connected, and somehow causing the starter to short.

So I'm just waiting on the warranty replacement for my failed 3 month old alt, to see if that will eliminate that short.