Starter troubleshooting - Page 3 - PeachParts Mercedes-Benz Forum

HuskyMan · #31 12-22-2016, 03:45 PM

I found the new Bosch starter on peach parts.

w123suv · #32 12-22-2016, 05:26 PM

Quote:

Originally Posted by HuskyMan

I found the new Bosch starter on peach parts.

It looks like they are all rebuilt but still high quality.

I did a little more work. Added a ground directly to the starter and tested voltage. Voltage to trigger wire with key was 9.2. Directly from battery with remote start cables 10.1. Both work and both fail to work. I also tried hitting it while holding down remote start trigger and it had no effect. I must have pressed the remote start button a dozen times with just a clunk. Left for two minutes to get a hammer and before I tried the hammer I hit the remote start button and it cranked over perfectly normal. Absolutely nothing changed in those two minutes. WTF! I think I am going to have to get a new starter because I don't know what is left?

Dan Stokes · #33 12-22-2016, 05:45 PM

I've seen similar before though I can't say that it's normal or abnormal. As others have stated, that's a LOT of amps being transferred right there. I'd for sure replace it - no reason not to other than cost.

Dan

funola · #34 12-22-2016, 06:10 PM

You already asked yourself: What is the chance that 2 starters behaved exactly the same way?. What's your answer?

I'll ask this: What is the chance a third starter will behave the same way?

I'd suggest taking MXFrank's offer and borrow the starter tester. If it works as advertised, will take the guesswork out of your measurements.

I'll take a voltage and current readings of my starter solenoid tomorrow so we can compare.

funola · #35 12-22-2016, 06:15 PM

Quote:

Originally Posted by w123suv

Here is what the old starter solenoid contacts looked like. Do not know if this is normal or not. The plastic broke on the way out so I could get a look at them. It looks like copper transferred from the lug to the plate over time.

How did you get it apart? The solenoid is a sealed unit and cannot be taken apart easily.

What do you mean "plastic broke on the way out" If the plastic was already cracked, It was likely caused by over torque of the solenoid nuts, as I mentioned previously..

w123suv · #36 12-22-2016, 09:11 PM

Quote:

Originally Posted by Dan Stokes

I think I answered that for you, or at least gave you a reasonable possibility. When you wack it, BTW, you can jar the commutator just a tad so that the dead segment is no longer contacting the brush and then it works until the next time it lines up - completely random. I understand that you don't want to pull the starter back out but think about your symptoms and who's suggestions make the most sense.

Dan

Somehow I missed your post. I am almost certain the problem is in the solenoid. If I jump the lugs on the solenoid the starter spins no problem. I also hooked voltmeter hooked up for continuity on the lugs and when I have the clunk symptom there is no connection between them.

Dan Stokes · #37 12-22-2016, 09:42 PM

That's a weird one but such things CAN and do happen. Best of luck - I'm holding on for the ultimate answer.

Dan

w123suv · #38 12-22-2016, 09:53 PM

Quote:

Originally Posted by Mxfrank

I have one of these gadgets, if you want to borrow:

Model 8540 | Associated Equipment Corp.

It will tell you whether the battery is holding up under starting loads and simultaneously tests the grounds, starter power connection, and the solenoid lead. It works by measuring the voltage drop at each connection. Someone gave this to me as a gift, I've never had reason to use it.

FWIW, I think Dan's nailed it. A fouled commutator or one open winding would behave like this.

Somehow missed your post yesterday. I really appreciate the offer. I found I great deal on the this and got it shipped new for $10.80! Otherwise I would have borrowed it but this is cheaper than shipping yours twice. I do not know if it will tell me anything new because I have done a lot of test with a voltmeter but... it seems handy to have.

w123suv · #39 12-22-2016, 09:55 PM

Quote:

Originally Posted by funola

How did you get it apart? The solenoid is a sealed unit and cannot be taken apart easily.

What do you mean "plastic broke on the way out" If the plastic was already cracked, It was likely caused by over torque of the solenoid nuts, as I mentioned previously..

When I was removing it the plastic broke because I was not careful with it. I thought I could get it out without taking the steering linkage loose.

barry12345 · #40 12-23-2016, 01:12 PM

I leant the hard way. When buying a German car starter as a rebuilt. If the solenoid does not appear new pass it by. I had various troubles with the rebuilts if the solenoid appeared old but just cleaned up.

It may have been a case of just bad luck on my part. . On the other hand it is an expensive part for a rebuilder to put in new.

I think the problem might be the solenoid may act very well on a test with twelve volts applied. The problem being the activation of the solenoid in the real world is getting much less than twelve volts.

Personally I want no cheaply reconditioned alternator or starter out of Mexico. Any rebuilder has a choice of very cheap parts or fairly expensive replacement parts.

The cheap replacement parts are so bad reputable rebuilders do not use them. I have used some of the cheap parts myself and they are seriously hit and miss at best.

There are one or two rebuilders in California that have a great reputation and are very reasonable in price. For most members even including the shipping you may land up with a quality rebuilt. Cheaper than the junk rebuilts some chain operations sell.

funola · #41 12-23-2016, 02:07 PM

Quote:

Originally Posted by w123suv

When I was removing it the plastic broke because I was not careful with it. I thought I could get it out without taking the steering linkage loose.

Did you pry it out? The starter should come out without having to remove any suspension components. It's a bit tricky but the procedure is well documented in what you need to do.

I measured the solenoid voltage and current while it was cranking: 9.5V @ 7 amps.

This is how it was measured:

Voltage at battery terminal = 12.7 V

Connected the small screw on the terminal block to + lead of digital volt meter, negative lead of meter to battery - terminal.

With another digital meter set on 20 amp scale, use meter leads to jumper the small screw on terminal block to the big screw. It starts cranking and the voltage and current values are displayed on the meters. Engine did not start (just keeps cranking as long as the terminals are jumped) since there was no glow and no fuel because the key was in the off position, shutting off fuel to the IP.

I did not measure with the starter not cranking. That's a lot more work, requiring disconnecting the big cable at the starter.

funola · #42 12-23-2016, 02:11 PM

Quote:

Originally Posted by w123suv

Somehow I missed your post. I am almost certain the problem is in the solenoid. If I jump the lugs on the solenoid the starter spins no problem. I also hooked voltmeter hooked up for continuity on the lugs and when I have the clunk symptom there is no connection between them.

You cannot use an ohm meter to measure ohms on the starter lugs with voltages on it, you will get an incorrect reading.

yuke · #43 12-23-2016, 04:21 PM

Quote:

Originally Posted by w123suv

Definitely not the NSW. That was my first thought because that has always been the problem before. I replaced it with a new Mercedes switch and thought I had it fixed for a week or two. That is how random this problem is.

I just disconnected all the wires. Everything looked fine. Old but no obvious issues. There is just the smallest amount of corrosion on the starter end of the small wire that activates the solenoid. See attached photo. I think I will replace this wire with new.

I am skeptical of this being the problem though. The solenoid never fails to make a strong clunk sound. Could lowered voltage due to resistance through this wire be enough to keep it from engaging the contacts firmly enough. Should I increase the wire gauge? Does this wire get power directly from ignition switch. I could add a relay on the fender in order to feed more amperage to the solenoid?

Pretty sure the problem is not before the connections on the fender because it happens no matter wether I use the key or remote starter straight from the battery.

123 look very closely and test that wire you have in the picture for continuity that wire is where my intermittent starting problem was. The wire looked good but it was not making a good solid connection all the time when I would tap on the starter it would start fooling me to believe problem was in starter. I think I finally found the problem when it did not start to trace each wire to see if it was delivering voltage or not. I have since have no problem starting ounce I replaced the end connection of that small wire. These cars are 32 yrs. old and the wires become very brittle and can break inside which you cannot see on the outside. Hope you figureit out.

w123suv · #44 12-24-2016, 03:48 PM

Quote:

Originally Posted by yuke

123 look very closely and test that wire you have in the picture for continuity that wire is where my intermittent starting problem was. The wire looked good but it was not making a good solid connection all the time when I would tap on the starter it would start fooling me to believe problem was in starter. I think I finally found the problem when it did not start to trace each wire to see if it was delivering voltage or not. I have since have no problem starting ounce I replaced the end connection of that small wire. These cars are 32 yrs. old and the wires become very brittle and can break inside which you cannot see on the outside. Hope you figureit out.

Replaced that wire completly. Unfortunately did not make a difference. It always showed voltage before and after but I replaced it just for heck of it. A waste of time I guess.

I really appreciate everyone's help so far. Even though I do not know excactly what is going on I have elimated what seems like every possibility outside of the starter solenoid. I am probably going to order a new Bosch unit and hope for the best.

leathermang · #45 12-24-2016, 05:38 PM

Find the closest Agricultural Town near you... find their Alternator/Starter repair shop.
These kinds of places fix starters for tractors and stuff you can not get new or rebuilt ones for....and you would not want to if they can be rebuilt anyway....
I did this when I was having Exactly the symptoms you describe....
They took it apart while I was standing there.... it turned out to be the three small screws in the end which hold the ' cage ' which hold the brushes....
It took a big vise and a lot of muscle to open it up... probably the first time since new... it was about 25 years old at that time...
So at some point you might need to just take it off and take it to a professional...