Time for an overhaul of my 1.9 '98 BMW Z3 Individual

[Matt Barnes]

well .. Another day off wasted... sorry... "invested" in trying to trace my Terminal 30 Not Ok fault

After convincing myself it was the ignition switch I purchased a new one........there was new hope new faith

Upon removing all the driver footwell trim I was greeted with this.... it looked old, it looked crusty and I hoped it was broken

So this all looks straightforward, two screws and a connector..... what could POSSIBLY go wrong....... oh... stay tuned !!!

oh by the way, this is the EWS immobiliser under the steering column

and this is how it plugs into the ignition, the black plastic cowl is the immobiliser "aerial" which picks up the chip in your key to release the immobiliser and allow the engine to crank

and here my problems started... the two screws that hold the switch in are grub screws. First one came out like a champ, second one slotted head split open and I had to drill it out. half of it broke off in the bracket ,I had to "fashion" a drill bit to get to it

And here's the old ignition switch, looks refreshingly old and hopefully burnt out

New ignition switch in

connected up my scanner full of glee and hope an got....

Key in ignition - Terminal 30 Ok Terminal R Off
Position 1 - Terminal 30 Not Ok Terminal R On
Position 2 - Terminal 30 Not Ok Terminal R On

so, exactly the same as I had before..... select option 1 to enter Depressed mode....

Key in Ignition Key in Position 1 and Position 2

Released means the EWS Immobiliser has recognised the key and allowed the Starter Motor to crank
Terminal 30 Not Ok means a vital 12v line is missing or grounded.

I took the ECU out .... again.. and pins 26 and 27 checked out for 12v and I cleaned up the ECU ground wires

The next stage was to pull every single fuse... I re inserted the ones that drove the onboard computer (so I could read it!)... and the immobiliser...

interestingly when I pulled the immobiliser fuse... Terminal 30 went to "Ok"... when I put it back it went to "Not Ok"... so I'm now thinking it's something in the immobiliser circuit... one of those is the clock. I did also notice that Fuse 31 that serves a lot of circuits made a little spark when I plugged it in... so something is not right.

 

[Matt Barnes]

ok so another four hours hunting down the issues.

decided to pull down the EWS module that sits behind the steering wheel under the footwell panels

and I have the worrying feeling someone has been in there before !

The EWS 3D has different pinouts than the EWS2 as it does away with the Transmit Module

So I started back probing every pin in every key position, but when I googled it, it suggested my pinouts weren't standard and the reason the car won't start is because my Terminal voltages are too low. Think my battery must have been suffering as earlier it was 12.1v on Pin 7.

Pin 1 is the thick Green/Black wire which goes to the starter circuit and Pin 15 is the small Violet/white which permanent 12v

anyway this is what I got, evidently both Pins 7 and 15 should both be 12.5v, pin 8 should be Ground but I was using a seat runner bolt as an earth so not ideal. BUT google suggests my Immobiliser is working but the voltages on Pins 7 and 9 are too low

Had enough of chasing voltages for one weekend.... Garden Parasol winder mechanism repair tomorrow !!

 

[Matt Barnes]

well that's another weekend of getting no further with the no start issues......I followed as much advice on line as I could and did find a couple of current draggers.... more of that in a bit...... right.. where to start

Put my freshly charged battery (13.7v) back in so there would no red herrings from a weak battery. Did a parasitic draw test and was a bit shocked by....

What the ???????....... then realised the modules were still awake from turning the key...... waited 30 seconds for everything to calm down with the key out.

and got..

78mA is still waaaay too much for..... oh... hang on... still got my scanner connected !!.. ooops

19mA... that's more like it !..... right... we're off diagnosing.... let's go !

I measured all the voltages again from yesterday and it was all the same... apart from the two 12.6v now reading a healthier 13.05 v on Pins 7 and 15 of the EWS connector.

the strange thing is, when I remove Fuse 45, my scanner reads Terminal 30 Ok in ALL key positions which is great but of course the EWS Release has now been disabled... BUT.. it's reading the correct voltage now for all key positions... so this is positive stuff

Google suggested one of the things which might drag Fuse 45 down is a short in the Instrument Cluster.... so I removed it

now then, this DID give me 12v on Pin 10 of the EWS, so there IS something wrong with the cluster that needs investigating

so.. I now have all the correct voltages at rest. Critically 12v on Pin 10 (yesterday was around 7v).

However, when I turn the key to Position 1, this drops to 6v. Not good. Google then tried to tell me this is a catastrophic failure of the EWS module as the relay is shorting inside the box. When I turn the key back off. when the relay de energises, Pin 10 goes back to 12v

So I'm losing 6 volts somewhere when I turn the key. This is my now infamous EWS 3D Immobiliser

I can't find an EWS 3D wiring diagram that matches my car, as evidently not all EWS 3Ds are the same !

oh the joys

So I decided to leave my bench like this..........

and go a drink a Hawkstones cider....