Yeah, that's helpful. Should probably attempt the disassemble first to see what/if breaks, and then purchase parts.

Now the starter has stopped engaging the flywheel. E.g. it starts off the first couple of revolutions engaged, but then starts to spin freely. I find this peculiar, because I thought the actual engagement purely is a mechanical function achieved through inertia and spring-load (independent of the faulty solenoid)?

Is the solenoid a sealed unit or does the assembly come apart?

Ok , on turning to start the engine , there was no noise, so the solenoid not even moving, the mechanical part was not throwing to engage the motor, this was the dirty bit and completely able to be dismantled ,as long as you can get the bolts out of the starter body( which was my problem and warranted my purchase of another starter) then a good clean up is all you need once off .

So I got the thing off and took it apart today. Apparently it's a re-manufactured unit (had a tag), and surprisingly little crud/dirt inside. I cleaned up what I could, the solenoid is a sealed unit and only the plunger/cylinder and spring is available upon disassembly. I was not able to engage the solenoid - apart from a couple of random jerks - in all the configurations I tried connecting the battery straight to the terminals (out of the two small, I take one is ground and the other is the 12V signal)?

Is there any reason I can't use a starter from an M57 outfitted BMW (730, 530, X5, etc.) - I see they are readily available locally and starting at 19 Euros at the German eBay. I'm a little confounded by the fact they seem to vary a lot in brand (have seen Valeo, Bosch, Denso, among others) and visual layout (I assume they are identical as far as power output and bolt pattern)?

https://www.ebay.de/sch/i.html?_from=R40&a...p;_sacat=0

TRy Gentlemen of salvage , not sure of the BMW one as postage is massive.Take time to secure replacement.

So, I got my hands on a 2nd hand starter from a M57 engined BMW X3. Surprisingly the starter motor/chassis is substantially smaller (and correspondingly I'd assume the kW output), but the solenoid is identical.

Story goes:

I hook the starter up with the cables on the car (using a ground clamp instead of bolting it on the bellhousing), and I get zero action from the ignition key. Unhooking it a testing the solenoid on the bench it seems to respond like it should. Bolting it back on the car (this time all the way), and still no reaction from the key (nor click from relay). WTF?

And here comes the funny part. Upon putting shorting the hot 12V from the battery to the small signal input on the solenoid, the starter will engage the flywheel for a couple of revolutions until it's relased somehow and the starter motor spins freely. WTF again?

From RAVE: "When the immobilisation ECU (C0059) receives an ignition crank feed from the ignition switch (and all other starting parameters have been met) it provides a feed to the starter motor solenoid (C0179) on a B then BY wire (...)"

What is meant by "B then BY", "then" as in some sort of progression? I assumed that the B is ground (it's thicker) and the BY (in my case it's black + green) is the positive starting signal?

Any suggestions that does not involve torching this pile to the ground?

This is the wiring diagram

Like we said right back in the beginning, it could be immobilized and it could be the wiring going to the starter from the ignition switch which is the fault i was involved with recently, the fact yours started and you don't have any fault codes in the security section would make me think it is just wiring.

The way we tested the other TD6 was to check there was 12.5 + volts going to fuse 53 i think it was in the glove box fuse box and then you would need to check the same voltage is on other fuses fed by the ignition barrel to start with including the cranking signal

Two things , make sure your battery voltage and current is up to values, and be sure that the solenoid is cleaned of all contaminated residues, it doesn’t sound as if your far off getting connections , they just need to be improved .

Thanks for the input!

I have tried to study the wiring schematics more than once, but I have an unfortuante tendency to get lost (especially when they mix TD6 with V - so bear with me.

I did indeed measure 12V+ on the top (ingoing) terminal of fuse 53. It looks like the current is looped through fuse 53 via the ignition switch (is this the actual key barrel?) back to fuse 6 (and then the alternator)?

Looking at diagram #2 it seems like fuse 25 only is relevant for V8 model? Also, what version of RAVE are these from? I have version LRL 0612NAS(2) and I'm not able to find the same diagram as #1, but a similar one for the V8 model (pg. 76)?

There is a reference to a jump start post between the hot lead and starter? Not sure if I have this?

Your jump start post is the black box that you flip down on the plastic bulkhead in front of the battery compartment unless somebody has removed it and you have a gaping hole.

That may be the V8 i posted already, i just searched the numbers from your post in the diagram, try this one for download

There is a whole bunch of wires going through the ignition switch, it is in two parts, the bottom part that can be changed houses all the contacts.

http://www.super7thheaven.co.uk/wp-content...k-2001.pdf

This is from the diagrams and is TD6, i'm afraid the quality is poor, i'll try and get a better pic but you can find it in the download

I am hoping i am not confusing the crap out of you... I think somebody has already mentioned checking the battery terminals are tight....

I’m not saying you haven’t bought a duff starter motor but I would try and verify if all your power supply is ok before changing too many components

It is a case of using the electrical library in conjunction with the wiring diagram and taking your time.

Try and follow the numbers first on the even more complicated diagram below and then the Letters to see the fuses you mention. When using the electrical library make sure you are in the TD6 section

Many thanks for the going through the trouble of drawing that up! At the risk of asking more silly questions, I don't see a reference to the letters you mention in electrical library? Will check voltage in/out to fuse #5 as well.

I took your lead on the ignition switch and tore into the centre console, disassembling the bottom unit from the ignition switch, opening it up and cleaning up the points and tips with Q-tips, air pressure and some 800 grit sandpaper topped off with electro cleaner. I found that one of the tips in particular had a good amount of dust/gunk built up and believed (somewhat excited) for a minute it was the culprit.

But alas, still zero action with the key in the 3rd position. Only difference now is a couple of electronic 'beeps' upon trying to crank (don't think I have heard these before).

I see fuse 53 feeds the main circuit into the switch, how do I find which actual cable comes from this fuse in order to confirm that 12V is present to the switch?

I also realize now that the BG wire to the starter solenoid is just a 'signal out' cable, which probably explains why the solenoid "pulls out" when I short across this and the main power to the solenoid?

The letters on the drawing I put up are what i added to try and show you how it flows through. i used numbers for one and letters for the other, is that what you mean by letters ?

Good effort on taking the centre console out but we only did that once we had verified it was the culprit by testing the voltages either side of it.

I would say you need to test what is actually going to the starter and if that is ok then it is still your starter, if it isn't ok then you need to work your way back using the wiring diagrams.

Regarding fuse 53, we tested it at the fuse to confirm that was ok and then if you follow the diagram it shows it feeds fuse 5 so if fuse 5 has the same voltage on it then that part of the switch is ok but you have multiple feeds coming out of the ignition switch going to other fuses so you can check them as well but you would have seen the ignition has multiple wires in and out and multiple contacts inside. Fuse 53 feeds fuse 5 which in turn feeds the alternator which then goes onto the starter motor and also the engine ECU.

Engine earth is another potential problem, you can test that by connecting a good jump lead to the earth point by the nearside turret and the engine, it is worth ruling it out.

Also you mention the black / green signal wire, this is connected directly o the engine ECU so i would be very careful about shorting across wires, i would much rather test for positive voltage than short anything out. As can be seen below from the description and operation part of the electronic library it is just a notification to tell the ECU to stop cranking as you have lazy starting that will continue cranking without you touching the key until the engine starts as you probably know.




We have already confirmed you have the park position symbol showing in the dash although i think it wont even let the key turn if it isn't in park or neutral

I interpreted that the letters were reference to the electrical library, but didn't see the connection when I looked? The numbers I understand to be the flow of the current, and at which points I should check there to be voltage?

I can in fact start the car by putting a screwdriver across BY and R on the solenoid in the diagram. So it's confirmed that the fault does not lie here somehow.

I did not get any voltage reading at fuse #5. I am measuring both posts and getting ground from the door hinge bolt (this seemed to work with fuse #53, although the number was bouncing around in the beginning I was able to get 12V). Could there be a short circuit in the (apparently very short run) between the fuses?

Also, forgot to mention that when I had the ignition switch apart I measured for continuity across all three internal terminals, and found that only the two inner prongs (furthest away from the barrel) actually made contact upon turning around the plastic cylinder. Aren't they supposed to, or could the tolerances really be so finite?

I agree that shorting the BG was a bad idea, as this is mostly a 'signal out' to the ECU as I understand. I did indeed verify that both this and the BY does not get any voltage when turning the key (or not).

On that last note, I do believe they key will turn in the ignition with the tranny in N (I'll verify this). Does this tranny have a mechanical neutral safety switch on the transmission itself? Would I be able to start it bypass the ignition (start on the solenoid) if NSS was indeed faulty?

If you tested fuse 53 and have 12.5 ish volts and then both sides of fuse 5( as in the fuse in place you can test the fuses with a pointed multi meter) with the ignition on and you have no voltage then i would say you need to change the lower part of your ignition switch.
This is taken from a conversation with the other guy that had a similar although worse problem.
Check your fuses for power with the ignition switch in the relevant positions.


Have a read of this BMW forum, you may have to register as if you read too many of their threads without registering they block you but really good forum so worth doing.
This thread had very similar problem to yours, only light on dash is airbag, problem starting with cranking ok but not starting and getting worse quite quickly which yours did and that was ignition switch but also same problem twice was a loose battery connection, i had to get some coarse emery cloth on the inside of the battery connector on that TD6 I had as that was showing signs of flat battery, might be worth doing next time you charge your battery as I know you like taking that battery in and out but your terminals looked good to me..

Also mentions fuel relay but i don't think that is relevant but can't be sure.
When yours was cranking and then started to do that half crank thing and then nothing points towards a connection getting worse.

https://www.bimmerforums.co.uk/forum/f18/2...art-t3083/

These are mainly notes for me as it is easy to read these off my phone if i come over.

I have had a read through the electrical manual and looked at the circuit diagrams - i may now be permanently cross eyed

As I checked the voltage of fuse 5 and that was only 2 volts or less I have looked at what other fuses are powered from the ignition switch to test although it may not be completely conclusive as there are a lot of red wires coming from the bottom of the switch so one could be good and another bad.

To test my theory of a faulty ignition switch and knowing that fuse 53 that supplies the ignition is ok and at 12 volts i will check during my next visit ....
Fuse 5 again to confirm only 2 volts.
Fuse 34 and fuse 2 should be live with the ignition

The transmission circuit
Fuse 53 and fuse 54 should be permanent live
auxiliary position on ignition fuse 37 (transfer box) should be live
when ignition on fuse 5 , 33 and 35(HDC) should be live.

Instruments panel
Fuse 27 (BCU), 46(Instrument panel) and 53 should be permanent live
auxiliary position on key - fuse 45 should be be live
ignition on, fuse 1 should be live and provides two feeds to the instrument panel.
The clock illumination lights should come on with key in auxiliary position and ignition on when the sidelights are on.

if this is an ignition switch problem then following link is somebody who took theirs apart and cleaned it.

https://www.aulro.com/afvb/l322-range-rove...witch.html

Hopefully this isn't a load of crap mate but i'm happy to check next time as it's easy for me to test voltages on fuses and if it the case i don't mind giving you a hand taking out the ignition switch as i know how these cars take over your head, I just treat them as a really annoying puzzle !!

This could still be something completely different mate as everything is linked together but it is a process of elimination