[AlexMason]

Hello guys,
I have e92 320d (N47) automatic 2010 with 93k miles.

I've got some strange problem with a starter.
Around 6 months ago I have replaced my starter with a "refurbished" unit. The reason was because my old one was "sticking" - i.e. not disengaging. When I was starting my car the engine was starting perfectly fine, but the starter would keep cranking and making a horrible and very loud noise. It got so bad that in it's later days it was taking more than a minute for it to disengage whilst I was driving with horrible noise and all the embarrassment.

Now this "new" starter is starting to develop the same issue - happened twice already in the past week and the time period is getting longer each time.

I'm now thinking - could this be something else? Because it's a very strange coincidence that a second starter would fail in the same exact way - and I think "not disengaging" is not very typical fail for them (correct me if I'm wrong)?

Any ideas guys before I chuck money on a new unit - could it be some relay or crankshaft position sensor etc? I don't have any fault codes though.

I also took apart the old starter today - and solenoid can move freely back and forth and the main starter's shaft was moving freely as well.

[Chapperss]

I`d go with the new unit fella. Don`t think it`s a conicience that it stopped when you put the referbished one in and now the refeurbished one seems to be failing to causing the same problem.

i`m not an expert on this engine and its foibles though... Have you searched the forums/internet for N47 starter motor issues to see if this is a common way for them to fail?

[Andystobbs]

Fords used to suffer this when the DMF was dying. Never seen it in a BMW but the Nx7 does have the starter right at the bottom. Check it's not covered in fine metallic dust on the pinion.

Ignore all that DMF bit. Just seen yours is an Auto. Still check it.

[AlexMason]

Originally Posted by Chapperss

I`d go with the new unit fella. Don`t think it`s a conicience that it stopped when you put the referbished one in and now the refeurbished one seems to be failing to causing the same problem.

i`m not an expert on this engine and its foibles though... Have you searched the forums/internet for N47 starter motor issues to see if this is a common way for them to fail?

Yes I have done some research and a starter not disengaging is a very rare one, at least there isn't much on Google or forum searches.
The very common way for them to go is - no crank at all.

[AlexMason]

Originally Posted by Andystobbs

Fords used to suffer this when the DMF was dying. Never seen it in a BMW but the Nx7 does have the starter right at the bottom. Check it's not covered in fine metallic dust on the pinion.

Ignore all that DMF bit. Just seen yours is an Auto. Still check it.

This is interesting actually as one lad on Facebook also suggested that it's a flywheel on its way out. But how would it make a starter shaft to not go back, I don't quite understand?

When I was looking at my older starter today I checked those signs - but honestly there was very little of metal dust mixed with some kind of grease. I'll see if I can post a picture tomorrow.
Also when changing the starter teeth on both flywheel and starter looked like they had no wear at all and were perfectly fine.

[AlexMason]

Also on a second thought taking in account it might be a flywheel. Why does it then keep cranking the engine if I shut the ignition off? So the engine is not firing (obviously because there is no fuel supply) but starter keeps turning it over , surely flywheel has nothing to do with it?

[Chapperss]

Originally Posted by AlexMason

Also on a second thought taking in account it might be a flywheel. Why does it then keep cranking the engine if I shut the ignition off? So the engine is not firing (obviously because there is no fuel supply) but starter keeps turning it over , surely flywheel has nothing to do with it?

If I understand a flywheels job correctly, it is a heavy rotational mass. So it may take a bit to stop spinning even with the starter connected to it.

[therealdb1]

Sounds to me like you may have an electronical problem rather than mechanical.

There could be a problem with the CAS where it is not signalling the solenoid to let go or there could be a communication issue between the DME and CAS so it doesn't know that the engine has started.

Alternatively it could be the solenoid is physically sticking in the on position.

My plan would be to temporarily attach a wire to the low current supply wire to the solenoid (not the big heavy one on the starter!) so that I could measure the solenoid volts during the starting process and once the engine is running.

This will tell you if it is the electrical drive circuit malfunctioning or the solenoid is sticking.

If the former then more investigation is required but I doubt that any of these scenarios will produce a fault code.

[AlexMason]

Originally Posted by therealdb1

Sounds to me like you may have an electronical problem rather than mechanical.

There could be a problem with the CAS where it is not signalling the solenoid to let go or there could be a communication issue between the DME and CAS so it doesn't know that the engine has started.

Alternatively it could be the solenoid is physically sticking in the on position.

My plan would be to temporarily attach a wire to the low current supply wire to the solenoid (not the big heavy one on the starter!) so that I could measure the solenoid volts during the starting process and once the engine is running.

This will tell you if it is the electrical drive circuit malfunctioning or the solenoid is sticking.

If the former then more investigation is required but I doubt that any of these scenarios will produce a fault code.

I'm leaning more towards electrical problem myself now. Could it be that the crankshaft position sensor is not detecting that the engine is running?
Also strange how after replacing the starter it all worked fine for 6 months and now it's going back again.

[therealdb1]

I suspect if it were a sensor there would be plausability codes showing up.

I'm not saying "no" but I would expect a fault code from a sensor.

What are you using to check for codes? Do you have a BMW specific reader rather than a generic one that only gives "P" codes?

Apart from the fact that the starter motor is in an awkward position, hence my suggestion of a temporary extension on the wire, why not check the electrical connection to the solenoid so that you can confirm what it is being asked to do?

The energise signal should be there during cranking obviously but that should disappear once the engine starts. If it doesn't you then have the problem of why but at least you know it is not the starter motor/solenoid.

If the drive signal to the solenoid is correct then you know the problem is most likely with your recon starter.

Refurbished units fail. I am on my third roof pump motor and the car has only 37,000 miles on the clock so the roof hasn't been opened millions of times!

[AlexMason]

Originally Posted by therealdb1

I suspect if it were a sensor there would be plausability codes showing up.

I'm not saying "no" but I would expect a fault code from a sensor.

What are you using to check for codes? Do you have a BMW specific reader rather than a generic one that only gives "P" codes?

Apart from the fact that the starter motor is in an awkward position, hence my suggestion of a temporary extension on the wire, why not check the electrical connection to the solenoid so that you can confirm what it is being asked to do?

The energise signal should be there during cranking obviously but that should disappear once the engine starts. If it doesn't you then have the problem of why but at least you know it is not the starter motor/solenoid.

If the drive signal to the solenoid is correct then you know the problem is most likely with your recon starter.

Refurbished units fail. I am on my third roof pump motor and the car has only 37,000 miles on the clock so the roof hasn't been opened millions of times!

I am using ISTA to read fault codes. Now, when I said "there is no codes" it's not entirely true, there are some - only they don't relate to a problem imho. There is a fault on gearbox switch position sensor and climate AUC sensor which don't bother me too much at the moment.

Thank you for your idea with a remote wire. I'll try to do it next weekend and see if I can "catch" a problem, it doesn't happen every time - primarily in the morning when all neighbours are still sleeping

[therealdb1]

Originally Posted by AlexMason

I am using ISTA to read fault codes. Now, when I said "there is no codes" it's not entirely true, there are some - only they don't relate to a problem imho. There is a fault on gearbox switch position sensor and climate AUC sensor which don't bother me too much at the moment.

Thank you for your idea with a remote wire. I'll try to do it next weekend and see if I can "catch" a problem, it doesn't happen every time - primarily in the morning when all neighbours are still sleeping

You have the right diagnostic tool which is good.
Let us know how you get on checking the solenoid.
Funny how cars always know the most inopportune times to throw a wobbly. I once had a VW Passat whose security system would occasionally lock me out of the car. It would be fine for months but would invariably fail when it was tipping it down with rain!
I had a secret bonnet opener attached and carried a 10mm spanner around with me so I could disconnect and reconnect the battery and then it would be fine again for a few more months. I never did find the cause.

[AlexMason]

Ok guys I have just chucked in another refurbed starter - this time bought from a different company and they give a testing diagram with it.
I just though if I'm gonna be jacking the car up and going under, I might as well swap it - 79£ is not that big of a deal.
So if this one fails soon I'm gonna take the car to a garage because it will be clear that it's something electrical related.
When changing the starter paid attention to a flywheel - teeth are perfectly fine and everything is bone dry, starter is fine as well.
I also done a bit of testing with my spare battery and tested my previous (first) starter - just hooked some jumper clamps on it directly from the battery and it worked perfectly fine (engaged and disengaged), however it was definitely terrible on the car. So I don't know if it's indeed something electrical or if starter behaves differently under load.