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

[Newtricks]

Z3 2.8 build month June 1999, registered March 2000. I believe EWS3D

This started a couple of weeks ago when I returned from taking it in for a pre-MOT check - parked up, moved a couple of cars to be able to get the Z3 by the garage, got back in the Z3 and the key just clicked - absolutely nothing, no crank. The car had been faultless going to and coming back from the garage (c 35 mile round trip). I had other work to do in preparation for the MOT, so I’ve been pressing on with that including refurbed starter motor and various vacuum hoses. I managed to lead myself to believe that the starter motor could be culprit (no such luck).

Still got a non-starting Z3. I’ve read a number of threads @mrscalex proving very detailed and in depth - I’m way out of mine….

I don’t know how to start diagnosing this current problem. The battery has plenty of charge.

Is there a quick way to determine where the problem is? Is bypassing EWS a possibility to see if that is the cause (I don’t want to delete it, I’d rather fix It).

Any assistance/advice gratefully received.

 

[IanA]

I had similar on my 2.0 just after I bought it!!!
If the battery has a good voltage- find out where those volts are going.
Remove and refit the battery terminal connections.
Check the starter cable voltage at the jump points under the bonnet- that will prove the state of your fused 300A cable from the battery.
Check the voltage at the fuse box busbar, not so easy as you'll need to remove the glove box to get at it. That is supplied by a fused 200A cable.
Whilst you're accessing either of those, check that you are getting volts on both sides of any of the large fuses- by the battery, and on the busbar.
If all of those check out you're into OBD scanner territory. I use a C110 with "pacman" adaptor into the socket under the bonnet.
Good luck.

 

[Newtricks]

Thanks @IanA - I have the same code reader as you and it shows no error codes. I did read a thread (was it yours?), where the clock kept resetting - I’ll check mine and the pointers you raise. I’m OK with a spanner and instructions, but I’m in uncharted territory for me…….

 

[jaguartvr]

As Ian said, battery terminal

 

[IanA]

Before I sorted some current leakage problems (turned out to be a seat motor switch) I fitted a battery isolator in order to retain charge. Problem was, it didn't always reconnect cleanly and would isolate at inconvenient moments. I removed it and those issues went away.

 

[NZ00Z3]

There are many parts to the EWS system. Here are a few checks:

• Take the cover off the DME enclosure under the bonnet/hood. There you will find a fuse cube with 5 fuse spots. With the key in position 2, do you have 12V to earth on all fuses? You should have. This confirms:
  • That the key has been recognised by the EWS.
  • That the drive away protection has been disabled.
  • If you do not have 12V, then diagnose the inputs to the EWS as the EWS thinks someone is trying to steal your car and has not disabled the drive away protection, or enabled crank.
• When you try to start the car, do you hear a click from the engine bay? You should. This is the starter solenoid operating as expected.
  • If it clicks but does not crank, then your problem is with the starter motor or the heavy electrical cables going to the starter motor. There should be 12V on the starter motor big cable all the time. Just the same as the jump start terminal.
  • If there is no click, them move to diagnose the EWS.
• Unplug the EWS. Jump the 2 big wires in the connector. Pins 7 and 8, wires GN/SW and SW/GE. Sometimes a 50A fuse is all you need. Try to start the engine.
  • If it cranks (it will not start), you have confirmed the starter motor and the ignition switch. The problem is the EWS starter relay. This is predicated on having 12V at the fuse cube in the DME enclosure. This EWS starter relay is in the EWS and can be replaced if you have the soldering skills.
  • If it does not crank, test for 12V on pin 8, GN/SW when you move the key to position 3 (crank). No volts, then it's your ignition switch or the 50A fuse F106.
• If you have to diagnose the EWS inputs:
  • Get your wiring diagrams from the Resources section of this forum (see blue ribbon at the top of your screen).
  • If your car is an automatic, then the range selectors switch is a common problem.
  • Read the attached document.

 

[IanA]

There are many parts to the EWS system. Here are a few checks:...

Super useful, NZ. many thanks.

 

[Newtricks]

Thanks @IanA , @NZ00Z3 , @jaguartvr - it’ll be the weekend (and hopefully dry weather) before I can work through all these.

I can fill in a bit more detail - I get lights on the dash, if I lock/unlock the car I get a click from the starter solenoid (ditto if the battery is disconnected) , if I try to start it again without locking/unlocking, I get no click at all

 

[t-tony]

That's sounds to me like the battery is dead.

Tony.

 

[Newtricks]

I had thought the same, but what was odd was that I had just driven home and all was fine. I have checked the charge in the battery (it’s fine). I’ve a number of pointers to follow up on - I’ll post an update after I’ve done them. Is there a way of getting EWS to reset (I don’t mean sync with DME)?

 

[Pingu]

That's sounds to me like the battery is dead.

Tony.

I was going to say similar when I read the first post.

Lots of people are fooled into thinking that a battery is ok when it has around 12v with no load. You really need to know what voltage the battery is when there is a load applied. If the battery drops below (10.5v I think), the car won't start. If it drops below (9.5v I think) it is totally toast and even a recharge won't sort it - even though a recharge may bring it back to 12v.

TL: DR - what voltage is your battery whilst you are trying to start?

 

[Newtricks]

I’ll measure it at the weekend with the headlights on and post what it’s measuring - it’s a few days back, but I ‘thought’ I’d measured at 13.5 (but it could have been wishful thinking/seeing what I wanted!) - we’ll see

 

[Pingu]

13.5v is a charging voltage. If is was that with your engine off, disconnect the battery immediately - you have a major problem

 

[Newtricks]

I had a free half hour; I’ve measured the battery voltage at the battery terminals, and on the battery cables in the boot (to check if the clamps weren’t on securely enough), with the headlights on, and with the ignition on, readings are;
13.16V (apologies for previous misleading post),
12.96V and
12.86V respectively.

In doing so I’ve realised the drivers’ door isn’t unlocking/locking from the key buttons and needs the key turning in the lock to action it. Possibly a daft question/complete red herring, but could a faulty/failing actuator be making EWS believe the door hasn’t been unlocked and is immobilising the car?

 

[Pingu]

If the engine is off, those voltages are too high. I've never seen a voltage that high on a battery that wasn't on charge. You may have overcharged the battery and caused some internal damage. I can't think what that damage could be, as all the types of damage that I am aware of reduce the voltage, not increase it.

Do you have another battery that you can try?

Have you tried disconnecting the battery and measuring the battery voltage? If it is less than the voltage you have with the battery connected, there is a rogue voltage somewhere on the car. Try measuring the voltage across the car's two battery leads, but with the battery disconnected.

If you have a voltage on the car you will need to eliminate this voltage. The best way is to and short the positive and negative wires? This may lead to a spark, so it is best to do this using some sort of resistor. You may also be able to eliminate the voltage by using your voltmeter, but it could take a very long time (as the internal resistance of a voltmeter is very high).

 

[Newtricks]

Cheers, yes the engine is off. I don’t have another battery to connect up unfortunately. I’ll do as you suggest - disconnect and measure across the cables.

I don’t keep the battery connected to a charger, when I‘ve needed to charge it I use an MXS5.0. Having said that it is a fairly new battery (I replaced the original (20-odd years old) earlier on in the process of trying to get this one road-worthy).

 

[Pingu]

What was wrong with the old battery? Did you just replace it because it's old? BMW batteries seem to last 20+ years with no problems. It's a shame that you disposed of it, as it may have been ok. I keep my old batteries unless they are completely knackered.

 

[Newtricks]

It was completely dead when I got the car, wouldn’t take any charge. I took it with me to get it checked before purchasing a new one.

 

[Newtricks]

I’ve followed @Pingu instructions above, and @IanA (although I stopped short of removing the glovebox to get at the back of the fuse box).
After disconnecting the battery cable and measuring them I could see some residual voltage in them (although very small 0.03v), reconnected the battery cables and the voltage in the battery now reads 12.99v. Jump lead points under the bonnet read 12.98v. I’ve downloaded @NZ00Z3 EWS documentation - it was that that has me wondering about the drivers’ door lock actuator (which is an issue that seems to have appeared with the non-starting issue). I’m probably deluding myself, but I’m going to strip the door and have a good look at the actuator and micro switches with some switch cleaner - in the vain hope that the non-starting turns out to be linked and simple to fix….

 

[Pingu]

The 0.03v is about what I would expect.

Did you short the two leads? Use a 1.5v torch bulb as a resistor. This will discharge any capacitors in the ECUs without harming them.

Your battery voltage seems a bit too high. How long since it was last charged? It should have dropped to between 12.2v and 12.7v after 24 hours.

Have you tried cranking the engine? What is the voltage when the key is in each of the different positions...?

0 - key out
0 - key in
1 - radio
2 - ignition on
3 - cranking

You may be able to see the multimeter whilst you do the test if you use the underbonnet terminals. Do all the tests with the door closed and the interior light off, and again with the door open with the interior light off.