starter motor keeps burning out

[autopian]

This is all above my head a little. Doesn't the alternator only run when the engine is running? I'm confused

its not the alternator at fault. forget that as a option.
cheers
Chris

 

[Frankie]

That's fine,I was curious as to why it was suggested though.

 

[Danny DeVito]

Some good points by autoplan, but I would also add

You say the starter is burning out - what is the evidence for this? Have the old starters been tested/stripped and analysed? - this would give some clue to the problem.

Test/stripdown of one or more of the 'failed' starters is the next thing imho. Plus as has been said, put it onto a star machine.

A good question, I wonder if the battery was disconnected for a few minutes then reconnect and give it a try before it goes back, because once the dash freezes up then most likely its not going to try and start until the ecu is reset. They may be just seeing it dead assuming it's faulty again , remove , replace and off it starts again. Whereas maybe a disconnect will reset the car and what may be more of an ign problem. Even unbolt the starter and crank the engine will show if it will turn under no load. I suppose too a mechanic with a spanner will be able to decide if the engine is very hard to turn over. Anyway reset is easy and only a few mins to do

 

[autopian]

That's fine,I was curious as to why it was suggested though.

the car won't start if you have a flat battery, as the alternator charges the battery this could lead to a non start and i think this is where some of the confusion lies but as the garage have already changed the starter twice this can be discounted, they would have picked the alternator as the initial fault and not changed the starter in the first place.
we can only offer an opinion based on the information provided. another possible fault which i have not mentioned is a poor connection but this would be picked up when checking the feeds and earth as mentioned in my earlier post.


cheers
Chris

 

[johnsco]

Can you smell burning from the starter motor ?
If it is electrically burned out, you should have a smell from the burned-out electrical windings.

 

[mafya]

I have dropped the car off at Europa this morning, the mechanic who removed the last starter said he tested the starter on the bench and the starter and the solenoid were gone.
I have put in the title that the starter keeps burning out but to be honest i don't know if it is actually burning out.
I asked Europa if they could tell me exactly what is happening to the failing starters and they said they just take them off and send them back to be refurbished so not much help there.
I asked if the car has been put on the star machine on previous visit and they said it had and just showed starter motor had gone.
They have said they will give the car a good going over to see what the problem is and think it may be an electrical issue. I have told them to keep the car for a week if need be to get to the bottom of this.
They have said it is a technical issue that Mercedes would like to get to the bottom of and will be asking other workshops if they have had similar problems on any other cars.
I will keep you all informed of any developements, just have to wait and see what happens.

Billy

 

[mafya]

A good question, I wonder if the battery was disconnected for a few minutes then reconnect and give it a try before it goes back, because once the dash freezes up then most likely its not going to try and start until the ecu is reset. They may be just seeing it dead assuming it's faulty again , remove , replace and off it starts again. Whereas maybe a disconnect will reset the car and what may be more of an ign problem. Even unbolt the starter and crank the engine will show if it will turn under no load. I suppose too a mechanic with a spanner will be able to decide if the engine is very hard to turn over. Anyway reset is easy and only a few mins to do

I tried the battery reset and it was still the same, they did say they would be looking at the ignition switch and also the starter circuit itself.

 

[autopian]

thanks billy, keep us informed. it would be intresting to see what they find.

chris

 

[mafya]

Can you smell burning from the starter motor ?
If it is electrically burned out, you should have a smell from the burned-out electrical windings.

My mistake, i have used the term burning out when failing would have been a better way to describe it. There is no burning smell and i couldn't tell you if it is electrically burned out as i wasn't shown any of the failed starters.

Billy

 

[Rory]

...the starter and the solenoid were gone.

Hmmm....both of them?

Sounds like the solenoid may be being held engaged as someone suggested earlier. Poss faulty ignition switch, or some other problem with the starting sequence that the car goes through?

 

[mafya]

Progress update

Just had a call from Europa and they said that the starter motor is burnt out. They have checked the ring gear and spline of the starter and no damage so they don't think it is staying engaged mechanicly.
The Europa mechanic asked me if when the starter is working it has problems or any delay in starting up and i told him no.
The car has been on the star machine and is not showing anything or any fault codes. They are going to contact Mercedes and are also considering if it may be the front sam unit.

Billy

 

[mafya]

Progress update

Just had a call from Europa, the starter motor has been removed and inspected and is definetly burnt out.
They say that the ring gear is not damaged and don't think it is staying engaged and asked if it ever gives problems starting when the starter is working which it doesn't.
The car has been on the star machine and nothing comes up. They say they are looking into the possibility it may be the front sam unit and are going to seek advice from Mercedes.

Billy

 

[mafya]

Hmmm....both of them?

Sounds like the solenoid may be being held engaged as someone suggested earlier. Poss faulty ignition switch, or some other problem with the starting sequence that the car goes through?

Just had a call from Europa, the starter motor has been removed and inspected and is definetly burnt out.
They say that the ring gear is not damaged and don't think it is staying engaged and asked if it ever gives problems starting when the starter is working which it doesn't.
The car has been on the star machine and nothing comes up. They say they are looking into the possibility it may be the front sam unit and are going to seek advice from Mercedes.

Billy

 

[autopian]

Just had a call from Europa, the starter motor has been removed and inspected and is definetly burnt out.
They say that the ring gear is not damaged and don't think it is staying engaged and asked if it ever gives problems starting when the starter is working which it doesn't.
The car has been on the star machine and nothing comes up. They say they are looking into the possibility it may be the front sam unit and are going to seek advice from Mercedes.

Billy

if the sam unit was faulty it could only signal to engage the starter motor, but they are saying the starter is not staying engaged? also the sam would not engage the starter unless signalled to do so via the ignition switch. if memory serves these were a problem.

cheers
chris

 

[mafya]

if the sam unit was faulty it could only signal to engage the starter motor, but they are saying the starter is not staying engaged? also the sam would not engage the starter unless signalled to do so via the ignition switch. if memory serves these were a problem.

cheers
chris

When i say starter is not staying engaged i mean that Europa believe the starter is not burning out due to keeping engaged after the car is started.
To be honest i think Europa themselves are puzzled.

Billy

 

[mafya]

if the sam unit was faulty it could only signal to engage the starter motor, but they are saying the starter is not staying engaged? also the sam would not engage the starter unless signalled to do so via the ignition switch. if memory serves these were a problem.

cheers
chris

When i say starter is not staying engaged i mean that Europa believe the starter is not burning out due to keeping engaged after the car is started.
To be honest i think Europa themselves are puzzled.

Billy

 

[grober]

I am slightly concerned that I have heard nothing on any electrical measurements made on the starting system. First thing to check with a DVM is whether you are getting the full voltage drop across the starter motor and nowhere else. Have they measured the current draw with a clamp meter during a normal start to see if any abnormal loads are being imposed on the starting system--- these are basic measurements which should have been done routinely after the failure of the first replacement? Europa are an MB official workshop I believe?? they should have access to test figures for this.

 

[autopian]

the problem is with some of these replacement units is where they are manufactured. i used to own an auto electrical workshop where we used to re-manufacture starters and alternators which when done would retail for around 50% of a new unit from the dealers, slowly we started to see imports coming in from India and the east where a new one could be purchased much cheaper than we could re-manufacture using OE quality parts, imports were never built to the same standard and had a higher failure rate. I'm not saying that this is the case but...............

chris

 

[autopian]

sorry message duplicated
chris

 

[BlackC55]

Have they checked the earth from the engine to the chassis?