Starter earth

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spike1
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Good evening all, I'm having starter motor trouble, it's intermittent, sometimes all I get is a loud click and no crank, it can take up to 10 - 12 turns before the starter cranks the engine, this is a fairly new starter around 5 years old, I had it changed before I brought the truck as there was a starter problem then, I still have the old one so thought I would get it refurbished instead of buying a new one,however the guy from Bedford Battery phoned me and after testing today and could find nothing at all wrong with the old starter motor, after telling him the symptoms he seemed to think it might be a bad earth, does anyone have any idea how to check it? Incidentally the truck has a new Varta battery fitted, the big very expensive square one. Thanks Paul

Pistonhead
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Re: Starter earth

Earth strap if loose could give an intermittent fault but I feel you have a starter solenoid issue more than anything else.

engine cranks, you definitely have an earthling issue.

Alternatively at the next non crank, use a long pole or wooden stick and thump the starter or solenoid body. An immediate start up after a thump is indicating a solenoid issue. You can also get a dead point on the starter armature where if the armature happens to stop at the dead point, starter will not turn. To test this the starter has to be stripped.

spike1
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Re: Starter earth

Evening all, had the truck in the garage for some minor bits and thought I'd get the starter changed to the original one, same problem still there an intermittent clunk coming from the starter, after a few try's the engine cranks fine, this is the same intermittent problem I'm having from two starters, seems too much of a coincidence to me, an auto electrician has mentioned a possible flywheel problem, has anyone come across this before? Thanks 

 

Noblebenn
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Re: Starter earth

Interested in following this, sorry if it is hijacking the thread a little. 

My G300 had a new starter motor when I purchased the car, not sure why, but it is struggling to start when the vehicle is hot. Has always been fine starting first thing from cold.

Sometimes it turns over a lot before starting and sometimes the starter motor spins out with a high pitched screech.

Took a video and showed to a very competent mechanic who said it was definitely the starter motor. It was fitted by a good garage that know Mercedes well and fully receipted, would a bad earth be the first place to start looking?

Thanks

 

 

Pistonhead
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Re: Starter earth

I am sorry to learn your starter problem has not been solved.

Now there is intermittent and another intermittent with more of a pattern.

If we are talking intermittent, that is random and occasional then it is very likely to be a starter solenoid problem but you have had a new starter motor with which would be a new solenoid. Talking of the latter intermittent, the one with some pattern then it is probable that the starter ring gear could be the culprit here. With this type of fault the starter pinion throws out but have no cranking.

This happens at one of three spots or three spots on the starter ring. When the engine stops it stops at certain points frequently which has to do with pressure above the piston when the engine is switched off. Excessive wear or ring gear damage can cause a dead cranking spot(s) very much like a starter motor dead spot except here the starter will turn and throw the starter pinion out.

There are two points for 'earthing' to check; first is the earth strap from the battery negative terminal to body chassis. This is a short piece, remove the chassis connection, clean and smear some petroleum jelly (Vaseline)  on the cleaned surface and refit. Do the same on the second earth strap and this is located on the gear box to chassis frame.

Note upon last replacement of starter motor, the mechanic should or may have noticed condition of starter pinion, if damaged he should have been alerted to possible starter ring state. Checking of starter ring gear can now be checked removing the starter motor visually inspecting starter ring all the way around, turning the engine in a clockwise direction only (looking from front of vehicle, backwards). Engine has to be turned bit by bit by a flat blade screw driver levered against the starter motor housing and the ring gear teeth. To turn clockwise the screw driver has to be inserted in the lower ring teeth (handle being top most) and levered downward.

I would dismiss a starter ignition switch issue as the starter does click therefore it is getting the signal from the ignition switch.

gav.helme
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Re: Starter earth

Sounds earth related...

You could run a "large" wire / cable from the battery earth direct to the starter earth connection and see if that helps... i have seen many vehicle earth leads break down internally

Gav

spike1
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Re: Starter earth

Problems solved!! Bare with me here I might be getting the explanation wrong, apparently there was a bad or loose live connection from the ignition, the electrician has bypassed this and put a direct feed via a relay to the starter, (if that makes sense) or I could have had a push button start fitted, I have put the original starter back on and it has not missed once, in fact it jumps into live a the first turn of the key, the rear wiper was a broken relay wire (black and green) that runs through the back door in the black sleeve and the front wiper was a loose relay wire on the indicator stalk (small black one) I also had the rear springs changed, the old ones were so compressed that you couldn't get your fingers between the coils, what a different ride now! Almost smooth lol! Thanks for all your input 

jdring
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Re: Starter earth

Good thread.  I learnt never to take a good earth for granted!

My 230GE Auto just failed to start last week. Ignition lights but no starter.  It was in park so I wiggled the gear lever but no change.  Battery strength seemed good - all lights etc strong.  I confess to calling the AA because I was in a paying car park and might have needed a removal!

We located the starter and gave it a tap and talked about the auto inhibitor switch - it was dark and I hadn't seen that the switch is all the way back on the lowest position.  Moved gear selector all the way back and back into parked and bingo - starter motor fine again.

So when this happened the very next time I got in the car, I suspected that switch again but no amount of jiggling it made any difference.  I got the avometer out and started checking for power to it but tbh that was hit and miss.

Then I read this and decided to at least trace and wiggle the earth straps and tap the solenoid.  One of those things worked. I think it was the strap connection to the solenoid, though that looked nice and oily not dry and corroded.  I cleaned and checked the battery earth end and connection to the battery housing earth point anyway.  No problems since.

Not ruled out the strap connection to the solenoid but that will be what I wiggle if it happens again.

As you suggest - unlikely to be the ignition switch.