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

[Matt Barnes]

So after being convinced the battery wasn't up to it, I spent over 100 quid on a brand new 640A cold crank 095 battery and................

....nothing... exactly the same. Starter spins, no firing... "Terminal 30 Not ok" on Key position 1

Google and AI now say... for a brand new 640 A battery not maintaining the 11v needed for the ECU, there is only one thing left. Your starter motor is pulling all the voltage down... recommend replacing the starter motor and this will solve your starting issues........

 

[Mazza]

Hi Matt,
I have a spare starter motor ( came off the donor car I had)

I looked on RealOem and it appears all Z3’s use the same starter motor.

This one was off a 2001 M43 facelift car

If any use, even just to test the problem out, then let me know

 

[ChrisD]

So after being convinced the battery wasn't up to it, I spent over 100 quid on a brand new 640A cold crank 095 battery and................

....nothing... exactly the same. Starter spins, no firing... "Terminal 30 Not ok" on Key position 1

Google and AI now say... for a brand new 640 A battery not maintaining the 11v needed for the ECU, there is only one thing left. Your starter motor is pulling all the voltage down... recommend replacing the starter motor and this will solve your starting issues........

Google/AI is a terrible tool to use for trouble shooting. It’ll only regurgitate commonly answered responses with no real ‘intelligence’ on whether this is accurate or even relevant to your particular issue.
From what you’ve posted, your starter motor is operating ok. Your engine ECU will operate below 9V, minimally down to 6V.
It is difficult to ignore your diagnostic tool complaining about KL30 suggesting that there remains an electrical problem with the permanent 12V/GND supply to the engine control system. If you have completed a systematic check of all the 12V/GND points on an engine schematic then it’ll come down to the basic checks of fuel, spark and air. And with the latter, you wouldn’t be the first to have forgotten to remove a shop rag used to block and protect the intake during strip-down.
Be patient, logical and systematic and you’ll get it resolved. Good luck!

 

[Matt Barnes]

Hi Matt,
I have a spare starter motor ( came off the donor car I had)
View attachment 368030

View attachment 368031

I looked on RealOem and it appears all Z3’s use the same starter motor.

This one was off a 2001 M43 facelift car

If any use, even just to test the problem out, then let me know

Thank you Malc... If I end up down that avenue I'll take you up on that....

 

[Matt Barnes]

Google/AI is a terrible tool to use for trouble shooting. It’ll only regurgitate commonly answered responses with no real ‘intelligence’ on whether this is accurate or even relevant to your particular issue.
From what you’ve posted, your starter motor is operating ok. Your engine ECU will operate below 9V, minimally down to 6V.
It is difficult to ignore your diagnostic tool complaining about KL30 suggesting that there remains an electrical problem with the permanent 12V/GND supply to the engine control system. If you have completed a systematic check of all the 12V/GND points on an engine schematic then it’ll come down to the basic checks of fuel, spark and air. And with the latter, you wouldn’t be the first to have forgotten to remove a shop rag used to block and protect the intake during strip-down.
Be patient, logical and systematic and you’ll get it resolved. Good luck!

thank you for your reassurance @ChrisD .. this is REALLY starting to bug me now...... yeah "Terminal 30 Not Ok" in key position 1 implies it's not receiving anything..... guess it's endless probing and continuity testing

 

[Matt Barnes]

Well I'm pretty certain now I have a parasitic drain... brand new fully charged battery I bought and fitted on Tuesday, is now reading only 1.2 v... in a way that's a good thing as something is definitely pulling it down.... now for the fuse pulling !

 

[Mint]

Check that your seat switches are operating correctly Matt. A seat motor takes quite a bit of current. If the seat is stuck, may be your problem..

 

[Matt Barnes]

Afternoon all ... well.... I think I've found it.... but no spoilers......

Today I dug out my Kewtech meter that can go up to 10A.... hooked it up in series with the Battery negative lead. Set to 10A.. and rested it on the rear quarter so I could see from the engine bay.

As you can see.... current draw was 3A !!!... with nothing on and no key in the ignition...

What the hell !!!???... that's something biiiiiig !

Anyway I pulled every fuse and relay individually, including the 40A one behind the glove box....

and my readings were between 2.78A and 2.9A.. so nothing of any real significance. so it's got to be big, right ?

Tested the resistance of the earth strap and I got between 0 Ohms and 0.1 Ohms, so it's not that.

Let's try the alternator yes ?... connections on the back are easy to get to .... Positive is 13mm and negative is 10mm

and would you Adam and Eve it !!..... 216 mA !!!

still didn't want to fire, I put it in limp mode (by disconnecting the ICV and TPS) and it fired up for about 3 seconds.

So what's next is to fully charge my brand new battery which is a 640 Cold Crank Amp battery and see where we go from there.

 

[Matt Barnes]

Check that your seat switches are operating correctly Matt. A seat motor takes quite a bit of current. If the seat is stuck, may be your problem..

Thanks @Mint ... I've had that one before !... gave the switches a good old wiggle this time around and they're all good.

 

[Duncodin]

Last time I had an issue with battery drain it was the passenger seat switch.

I'd been in the passenger seat, missus driving, and slid the seat as far back as it would go. When we got home we got out, locked up. Next morning battery was deader than a dead thing. I assumed the battery was duff so bought a new one. Connecting the new battery I knew something was wrong by the size of the spark as I connected the battery. Checked the seat switches. The passenger seat was still trying to back itself into the boot. Once it starts rolling the motor keeps going even with the ignition off.

You'd think there'd be a limit switch that kills the motor when it reaches the end of the rail but if the seat is reclined just a little then that prevents the seat reaching the limit. In my case the switch was just jammed in the <Back direction. I guess it hadn't been used for years and just cruddy so didn't reset when I let go of it.

 

[Matt Barnes]

Last time I had an issue with battery drain it was the passenger seat switch.

I'd been in the passenger seat, missus driving, and slid the seat as far back as it would go. When we got home we got out, locked up. Next morning battery was deader than a dead thing. I assumed the battery was duff so bought a new one. Connecting the new battery I knew something was wrong by the size of the spark as I connected the battery. Checked the seat switches. The passenger seat was still trying to back itself into the boot. Once it starts rolling the motor keeps going even with the ignition off.

You'd think there'd be a limit switch that kills the motor when it reaches the end of the rail but if the seat is reclined just a little then that prevents the seat reaching the limit. In my case the switch was just jammed in the <Back direction. I guess it hadn't been used for years and just cruddy so didn't reset when I let go of it.

totally agree @Duncodin .. I had that several years ago with a permanent flat battery and that was the seat switch... this time it look like I need a shiny new alternator

 

[Mazza]

M44 or M43 engine ???
I have an alternator for an M43

Edit ……should have looked at your details on the left where it says M44 …..

 

[Matt Barnes]

M44 or M43 engine ???
I have an alternator for an M43

Edit ……should have looked at your details on the left where it says M44 …..

thank you mate..as always !... I'm going to try starting it today with a fully charged battery..if I still get "Terminal 30 Not Ok" at key position 2 again... I will genuinely break down and cry...

 

[Matt Barnes]

well.... here we go again.....

After more parasitic drain testing, I found the radio and driver's electric seat were indeed also pulling it down. So with those fuses removed, this got my final draw to 20mA.. absolutely bang on.

Tested the new Inlet Control Valve again, all good... had to get a bit creative and rest it on the intake manifold with a torch shining on the flap so I could see it move while cranking .... ..that's as far as it opens... about 3mm... which apparently is correct

Took the ECU out about 4 times to check voltages on the connector at rest and on cranking... all by the book in terms of voltages.

The M44 engine uses the Motronic 5.2 DME and out of 88 pins, only 19 are actually used !... for reference Pjn 1 is top right

Pin 27 (permanent live) and Terminal 30 both sat at 12.9v. on cranking they dropped to 11.0v which is evidently completely normal.

Thought it might be the Crankshaft Position sensor as if you look at my scanner, the demand was different from what the sensor was reporting

Again google suggested that the CPS was working as designed.....

However, you don't have to be Poirot to work out someone's been at the ECU before !

I tested the DME relay... again... and all good

With the TPS and ICV disconnected, the car enacts a pre programmed limp mode which means it ignores all the sensors for about 3 seconds, hence it runs for 3 seconds. Google now suggests with everything tying up I must have a massive air leak.... but I don't ...

Time for some more drinking... I mean thinking....

 

[Duncodin]

well.... here we go again.....

After more parasitic drain testing, I found the radio and driver's electric seat were indeed also pulling it down. So with those fuses removed, this got my final draw to 20mA.. absolutely bang on.

View attachment 368158

Tested the new Inlet Control Valve again, all good... had to get a bit creative and rest it on the intake manifold with a torch shining on the flap so I could see it move while cranking .... ..that's as far as it opens... about 3mm... which apparently is correct

View attachment 368155

Took the ECU out about 4 times to check voltages on the connector at rest and on cranking... all by the book in terms of voltages.

View attachment 368160

The M44 engine uses the Motronic 5.2 DME and out of 88 pins, only 19 are actually used !... for reference Pjn 1 is top right

View attachment 368156

Pin 27 (permanent live) and Terminal 30 both sat at 12.9v. on cranking they dropped to 11.0v which is evidently completely normal.

View attachment 368157

Thought it might be the Crankshaft Position sensor as if you look at my scanner, the demand was different from what the sensor was reporting

View attachment 368159

Again google suggested that the CPS was working as designed.....

However, you don't have to be Poirot to work out someone's been at the ECU before !

View attachment 368161

I tested the DME relay... again... and all good

View attachment 368162

With the TPS and ICV disconnected, the car enacts a pre programmed limp mode which means it ignores all the sensors for about 3 seconds, hence it runs for 3 seconds. Google now suggests with everything tying up I must have a massive air leak.... but I don't ...

Time for some more drinking... I mean thinking....

I'm an old guy. Even though I'm a software engineer all this TPS, ECU, STD m'larky is over my head. If this was an old 'analog' car I'd be saying it sounds like a fuel pressure issue where switching on the ignition key builds up pressure in the fuel rail just enough to start the engine but once its running the fuel pressure drops and kills the engine after around 3 seconds.

But I guess with more computers than you can shake a stick at it has to be a computer issue rather than a simple pump/return valve issue.

Did you observe the fuel pressure constantly during the 3 second running

 

[Matt Barnes]

I'm an old guy. Even though I'm a software engineer all this TPS, ECU, STD m'larky is over my head. If this was an old 'analog' car I'd be saying it sounds like a fuel pressure issue where switching on the ignition key builds up pressure in the fuel rail just enough to start the engine but once its running the fuel pressure drops and kills the engine after around 3 seconds.

But I guess with more computers than you can shake a stick at it has to be a computer issue rather than a simple pump/return valve issue.

Did you observe the fuel pressure constantly during the 3 second running

To be fair I haven't had the scanner running while in limp mode....that could be interesting!

 

[Matt Barnes]

well... I've run out of ideas for now... Scanner is reading the Crankshaft position sensor at 240RPM on cranking, it's reading the throttle body position in percentage (which means the Throttle Position Sensor is working), the ICV opens on cranking. I took the inlet manifold hose off and there was a little tear by the jubilee clip which I repaired. Every value I'm recording is evidently correct... well.... according to Google !

I still get "Terminal 30 Not Ok" at Key position 2 regardless of what I do, which evidently is preventing it firing (still fires in limp mode)

On the plus side... I did manage to repair the driver's door handle and refit the door card..... which was nice !

 

[Matt Barnes]

well this is interesting, I looked at my Scanner at differing key positions and this is what I got, in terms of voltages and what google diagnosed it as

it can't be the jump posts in the engine bay as they read the same as the battery in the boot.... one alternative is....

2. Burnt Internal Contacts in the Ignition Switch
The mechanical contacts inside the BMW Z3 Ignition Switch Electrical Base can pit, burn, or wear out.

• The Fault: When the switch physically rotates to bridge Terminal 30 to Terminal R, carbon build-up or a weak internal spring prevents solid contact, creating massive electrical resistance.
• The Fix: Unplug the switch harness and perform a continuity/resistance test across the pins, or bypass it temporarily to see if Terminal 30 stabilizes.

Perform a Loaded Voltage Test at the Ignition Switch:

• Access the back of your ignition switch.
• Locate the thick Red wire (Terminal 30 incoming permanent power).
• Measure the voltage on this Red wire with Key Off (should be ~12.6V).
• Keep your voltmeter leads attached and turn the key to Position 1.
• If the voltage on the Red wire crashes below 10V, your problem is before the ignition switch (battery cables, firewall post, or fusible link).
• If the voltage on the Red wire stays at 12.6V but the output wires drop, your ignition switch base is faulty.

Well that's next weekend's job !

 

[Mazza]

sent you a link on wattsup
I came across it

 

[Matt Barnes]

sent you a link on wattsup
I came across it

thanks Malc... got it !