Z3 2.8 not starting (doesn’t turn the crank either) EWS? Any assistance gratefully received

[Newtricks]

I did attempt to short them - basically touched them together. All the same dash lights still come on. I’ll take some other measurements in the different ignition positions - whilst I can turn the key to where it should crank, it currently does not crank at all.

I charged it Thursday before commencing this (I let the MXS5.0 cycle through all it’s steps (including the desulphurisation etc)) and disconnected when it completed (not going onto the maintenance options).

 

[Newtricks]

That proved to be interesting, and educational for me (even though I don’t know what it means);
Door Open
key out - 12.9v
key in - 12.9v
pos 1 - 12.82v
pos 2 - 12.66v
crank - 12.59v (it doesn’t attempt to turn the engine over)

Door Closed
key out - 12.72v
key in - 0v
pos 1 - 0v
pos 2 - 12.69v falls quickly to 0v
crank - 0v (it doesn’t attempt to turn the engine over)

 

[Pingu]

That's interesting info and should help the diagnosis. I'll check the wiring diagrams.

 

[Newtricks]

Thanks @Pingu for your help, I’d have no idea where to start. I’ll press on with changing the oil seals in vanos solenoids, and I’ve ordered some contact cleaner to pick up tomorrow so that I can have a look at the lock actuator.

 

[Pingu]

Does the interior light above the mirror work with the door opening and closing?

 

[Newtricks]

Yes it does, probably the only thing that is working properly!

 

[Pingu]

That proved to be interesting, and educational for me (even though I don’t know what it means);
Door Open
key out - 12.9v
key in - 12.9v
pos 1 - 12.82v
pos 2 - 12.66v
crank - 12.59v (it doesn’t attempt to turn the engine over)

Door Closed
key out - 12.72v
key in - 0v
pos 1 - 0v
pos 2 - 12.69v falls quickly to 0v
crank - 0v (it doesn’t attempt to turn the engine over)

Strange that the battery is 0v at any time. I suspect that your clips fell off the terminals.

Anyway, take off the cowling that surrounds the ignition switch.

Using a test lamp, test the large red wire (4mm²) for 12v. It should be 12v all the time.

Test the Black/Yellow 2.5mm² wire for 12v when the key is in position 3 (cranking).

If the Black/Yellow is not 12v - DO NOT BE TEMPTED TO JUMP THE CONNECTORS. You can damage the cat if you crank the engine with the ignition off. More investigation is needed.

 

[Pingu]

Yes it does, probably the only thing that is working properly!

That confirms that the door switch is working properly and that the ZKE module is earthing properly through the switch. One thing ruled out .

Although the door switch controls lots of things, there is only one wire - and it comes from Contact #2 on the ZKE. It is the ZKE Body Control Unit that does all the linking of the functions. In the old days there would have been multiple wires coming from the door switch and going to each of the different things that are controlled.

 

[Newtricks]

I don’t have a test lamp, is it OK to do those tests with a multimeter?

 

[Pingu]

You can do, but a multimeter doesn't draw any current, so will show 12v even if there is only a single strand of wire making the connection (or a dodgy solder joint).

Multimeters are good for testing ECUs (as ECUs use very low currents and have fragile internal connections and components).

A 2W test lamp is better for testing wiring for the reason I gave earlier. A 2W bulb will draw 0.16A from a 12v battery. That should be more than enough to find a dodgy solder joint or single strand wire.

 

[Newtricks]

I can confirm the larger Red wire is 12V (around 12.8v). Being a bit thick I’m afraid - photo attached. Is it the yellow and black wire in the very left slot of the connector with the yellow label?

 

[Pingu]

I've looked at a few Z3 wiring diagrams and they are all the same for the ignition switch...

Feed = Red (4mm²)
Radio = Violet (2.5mm²)
Start only = Black / Yellow (2.5mm²)
Ign only = Green/White (0.5mm²)
Ign & Start = Green (2.5mm²)

It looks like the wire that you need to test is the one that looks brown in the picture and goes to the terminal at 9 o'clock. It's below the thin green one.

At the bottom of the image of the ignition switch is the connector that connects to the toroidal coil around the key. Do you have a spare key? There is a possiblity that your key is not being read by this coil. I'm not sure how to test it. I would probe it with a multimeter to see if there were a reading, but I can't advise you to do that as it might cause damage.

Edit - Having just read the PDF, probing the connector won't tell you much, as the connector is used to power the transponder in the key. That transponder then sends a code down the same wires to the EWS unit. It checks the code and begins the start sequence (crank the engine, activate ignition, activate injection, send new code back to key and more).

 

[Pingu]

I've just read the PDF that NZ003 attached and you will have the EWS III D which is on p.23 (but it's a good idea to read the whole thing). It explains why just bypassing the starter is not a good idea (as the ignition and injection are still disabled if the key is not recognised).

 

[Newtricks]

Thanks @Pingu for all your patience and help - I’ve ordered a circuit tester light. I’ll test the wire you’ve identified just now and post a result. I‘ve 3 keys - one is an original (that looks like a typical ‘older‘ car key, and 2 with folding blades), all will lock/unlock (actuator problem no withstanding), none will start the car.

 

[Pingu]

I suspect your key., but it's best to rule out the easy-to-check stuff

 

[Newtricks]

I’ve measured the wire (I think it might be Red and Green), with 2 keys. It measures c12.6v (fluctuated quite a lot), but in Pos 3 it’s a solid 0v. Hopefully this makes sense.

I certainly don’t want to delete or bypass EWS long term - everything I’ve done is to try and maintain original spec.

 

[NZ00Z3]

Go back to post #6 and do the first black bullet point. That will confirm if the key is being recognised or not.

 

[Newtricks]

Thanks @Pingu for your assistance in getting this far. I’ll check tomorrow whether any of the keys are being recognised and take it from there. I’ll still have a look at the door lock, as that fault seems to have manifested at the same time as this and I’m not a fan of coincidence, and it needs sorting anyway. I’d printed and read the EWS document @NZ00Z3 had provided, and was that that first got me thinking about maybe the actuator and this were linked (freely admit I’m potentially leaping to conclusions). More anon!

 

[NZ00Z3]

Another approach is to get set up with a scanner that has BMW software and see if there are any trouble codes in the EWS.

INPA is a cheap option: https://www.bimmerforums.com/forum/...tions-Experiences-Discussions-Experimentation

 

[Newtricks]

Thanks @NZ00Z3 - I’ll follow the steps you proposed earlier in the thread first, my simple code reader isn’t finding any errors and I’d investigated downloading INPA, but stockists of cables in the UK seem to be out of stock at the moment (I read it’s delays from the manufacturers) so I parked it for the moment as it isn’t going to be any faster.
If I‘ve read and understood the pdf you helpfully posted it seems that the issue is either before EWS, or with EWS as a do not start message is being sent. Whilst I have the steering cowling off I had a look at the ignition lock aerial - visually it looks OK, all connections seem solid, and for the measurements I took with guidance from @Pingu there is a small voltage draw with a key inserted.
The faulty door lock actuator manifested pretty much at the same time as this problem, and EWS document indicates a feed from the lock to EWS (and subsequent start/no start message).
Whatever the problem turns out to be, all 3 keys (that were all useable) are impacted.
I’ll post the results of the steps you suggested.