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DISCUSSION => General Topics => Topic started by: maximan on November 06, 2012, 06:43:30 AM

Title: M42 start issues. Starter not always turning
Post by: maximan on November 06, 2012, 06:43:30 AM
Hey guys (and/or girls!).
I am new to this forum and about to start to bother you with my problems ;)

I have some problems with my M42 engine lately.

I live in Europe and this is a E36 with a M43 to M42 conversion.

So to the problem:
Starter will not turn. It kicks in but will not turn, and the lights in the car is dimmed, just like with low battery. I have changed the battery and the starter to a used one but no change.
Sometimes the starter is spinning without entering the clutch house.

This problem is sporadicly turning up but it is worst when it is cold.

When it occurs it will eventualy start after a cople of dozens tries.

This is very annoing and i would really appritiate your help!

I have a couple of videos of the problem and will upload this as soon as i get home from school.

Please excuse and note that english is not my main language, but i will try my best!

Thanks in advance!
Title: M42 start issues. Starter not always turning
Post by: romkasponka on November 06, 2012, 07:05:48 AM
Check ground cable engine-chassis, battery cables and ground studs for condition. Sometimes ground cables, studs are corroded and oxidized and have big resistance so with big load (A) traveling through you loose some voltage and power.
Title: M42 start issues. Starter not always turning
Post by: maximan on November 06, 2012, 07:35:56 AM
Good idea!
I did the engine switch myself before the summer and i connected the engine to chassis lead good.
I used different studs when i changed the starter.

Do you know what kind of A that should be going through the starter when cracking engine?
Title: M42 start issues. Starter not always turning
Post by: romkasponka on November 06, 2012, 10:00:32 AM
I think it is 100-200A

P.S. http://www.aa1car.com/library/1999/cm119948.htm
Title: M42 start issues. Starter not always turning
Post by: maximan on November 06, 2012, 01:42:48 PM
Ok. Will check.

I have forgot to mention that the engine worked for months without the starter hesitating until one night it just wouldnt start.

I jumpstartet it and it smelled a little burned. It is possible that i have burned som of the wiring?
Title: M42 start issues. Starter not always turning
Post by: romkasponka on November 06, 2012, 06:19:29 PM
Everything is possible but lets hope you have not burned any wiring.
Title: M42 start issues. Starter not always turning
Post by: DesktopDave on November 06, 2012, 07:34:44 PM
I'd check the 'bendix' drive...also called a starter solenoid.  It engages the starter motor into the flywheel gear.  They can be removed & swapped between starter motors.  Also check the flywheel for damage like a 'flat spot' that the starter gear cannot engage.
Title: M42 start issues. Starter not always turning
Post by: maximan on November 08, 2012, 08:40:43 AM
Quote from: DesktopDave;117459
I'd check the 'bendix' drive...also called a starter solenoid.  It engages the starter motor into the flywheel gear.  They can be removed & swapped between starter motors.  Also check the flywheel for damage like a 'flat spot' that the starter gear cannot engage.


To do this i will have to remove the starter?
I hoped for some easy check points to begin with since i am currently living in a student home and dont have any tools and its below zero outside.

Anywa, thanks for the tip:D
Title: M42 start issues. Starter not always turning
Post by: Geoff on November 08, 2012, 11:54:18 AM
I suppose (but accept no respnsibility)  that one seat of the pants test is just put 12 volts from a known good battery (I use a jumper cable) to the pos terminal of the starter with the car in nuetral and the key off.   If the starter is alive and well,  it will turn the engine, (but of course not start) and so now you know that the starter works, and the problem is a lack of power to the starter.        Having said that,  it kinda sounds like the starter may be fokked, altho they are fairly reliable as starters go
                                                                        Geoff
Title: M42 start issues. Starter not always turning
Post by: maximan on November 09, 2012, 05:54:55 AM
Quote from: Geoff;117493
I suppose (but accept no respnsibility)  that one seat of the pants test is just put 12 volts from a known good battery (I use a jumper cable) to the pos terminal of the starter with the car in nuetral and the key off.   If the starter is alive and well,  it will turn the engine, (but of course not start) and so now you know that the starter works, and the problem is a lack of power to the starter.        Having said that,  it kinda sounds like the starter may be fokked, altho they are fairly reliable as starters go
                                                                        Geoff
I would think so too. Specially since i have already changed the starter once just months ago.
I am thinking about stretching a ground cable from the starter motor chassis and straight to the battery. Will that work or will i short circuit?

There is a short thick cable that goes from the plastic on the bendix drive and to the chassis of the starter. I am thinking about connecting it to that?
Title: M42 start issues. Starter not always turning
Post by: Geoff on November 09, 2012, 06:23:04 AM
the starter is grounded by virtue of being bolted on.  this can be a problem if the chassis ground  is questionable.  you should only have to apply positive to the positive lug on the solenoid (usually a red rather heavy wire)  and you can touch the body of the statrer with the negative side of the battery you are using and it should ground it.   Get someone to give you a hand if you are not sure where to attach the wires because you could short things out if you mistakenly connect power to a ground point.
                                                              Geoff
Title: M42 start issues. Starter not always turning
Post by: maximan on November 09, 2012, 08:17:32 AM
I will ask some of my buddies to help me:) Better with 2 thinking heads.
This is how i think about grounding the starter.
Hope it is understandable.
(http://www.m42club.com/forums/attachment.php?attachmentid=2326&stc=1&d=1352470543)
Title: M42 start issues. Starter not always turning
Post by: Geoff on November 09, 2012, 10:02:13 AM
I think you've got it.   if it does not work right away,  you may haveto put 12v  pos  to the small terminal  also.  you can usually (carefully) use the jumper cable to make both connections by rocking the connector over to the side to touch the smaller terminal...space is a little tight also which does not help
             starters can be tested this way off the car too, but hold it to the floor with your foot or use a vice as it will jump if it works
                                                                           Geoff
Title: M42 start issues. Starter not always turning
Post by: romkasponka on November 09, 2012, 11:12:40 AM
I think it is wrong!

http://www.wolfsburgwest.com/wired/wired_03_01/wired_03_01.htm

Should be like this:

(http://img855.imageshack.us/img855/664/inv00053302.jpg)
Title: M42 start issues. Starter not always turning
Post by: maximan on November 09, 2012, 05:12:50 PM
Will not grounding the lower nut be the same as grounding the starter chassis as it is all metal?
hmm interesting. Do you mean that the starter relay is in the bendix drive?
How does the M42 starter terminals actually work?
I mean, what do the do?

Hope you guys dont think i am to much of a pain. I find it interesting finding different solutions;)
Title: M42 start issues. Starter not always turning
Post by: Geoff on November 09, 2012, 06:32:41 PM
It really looks like the same thing to me..what up,  Romkasponka?  I mean not the same but will have the same effect.
                                                                        Geoff
Title: M42 start issues. Starter not always turning
Post by: romkasponka on November 10, 2012, 04:33:05 AM
(http://img407.imageshack.us/img407/8117/starter2k.jpg)


Bendix
(http://img255.imageshack.us/img255/958/solenoid.gif)

Quote
Will not grounding the lower nut be the same as grounding the starter chassis as it is all metal?
Correct.

Quote
hmm interesting. Do you mean that the starter relay is in the bendix drive?
Yes and no. Lets say it is contactor for high A and it engages starter motor with flywheel.

Quote
How does the M42 starter terminals actually work?
I mean, what do the do?

I drooped you a link there is good explanation. Big terminals inside bendix are shorted then you crank engine. Small terminals are to energize contactor and engage starter with flywheel.
Title: M42 start issues. Starter not always turning
Post by: romkasponka on November 10, 2012, 04:46:12 AM
Quote from: Geoff;117530
It really looks like the same thing to me..what up,  Romkasponka?  I mean not the same but will have the same effect.
                                                                        Geoff

It wil not have the same effect. You will weld something because will make Short circuit when you energize bendix if you will try to do it like in maximan picture ;)
Title: M42 start issues. Starter not always turning
Post by: maximan on November 10, 2012, 06:34:01 AM
Very nice explenation!
I begin to think that the bendix drive is the sinner here.

But i there was one thing i didnt understand.
You mean the current passes through the leader in the bendix drive and then through the unisolated cable into the stator and then to ground?

It seems it is no easy solution here other than replacing the starter motor again:(
Title: M42 start issues. Starter not always turning
Post by: romkasponka on November 10, 2012, 07:04:27 AM
Quote from: maximan;117537

But i there was one thing i didnt understand.
You mean the current passes through the leader in the bendix drive and then through the unisolated cable into the stator and then to ground?


Yes.
Title: M42 start issues. Starter not always turning
Post by: Geoff on November 10, 2012, 07:17:53 AM
thats a good explanation.  now I even understand it:rolleyes:
Title: M42 start issues. Starter not always turning
Post by: maximan on November 10, 2012, 08:12:51 AM
OK :D Glad we have it all sorted out!
It seems that i will have to replace the starter/bendix. Not what i hoped for but thats it.
It seems the problem is found, but the thread will be open in case i need more help or other have similar problems.

Thanks a bunch you guys!