Another crank, no start.

[Steve C]

Spent the last 2 weekends in the garage and starting to run out of steam.
Tried re-alignment again with Rheingold.
Studied wiring diagrams to trace input/outputs.
I think if I knew what the DME was expecting from the seperate modules I would have a better chance.
Will probably leave alone until some inspiration or boredom leads me down the garden path.

Mrscalex.. If you are ever down this way, you would be most welcome to pop in.

 

[Andyboy]

I had an Audi recently with a weird starting problem - occasionally it wouldn't start. Then you'd release the key and try again - bingo.

Was the crank sensor. It all checked out OK, but it wasn't. For the sake of a few quid and 20 minutes work I'd replace it with a used one. Fault codes often mean nothing - for example, a failed MAF won't show a fault code at all.

EWS1 used the high/low signal from the door locks to the body control module and then to the starter relay and the engine ECU via the OBC if fitted. That was 9/1993 to 12/94 though.

EWS2 arrived on all BMW's in 1/95 and was the chipped key talking to the EWS module via the plastic ring.

Have you checked that the car hasn't got an alarm immobiliser? A lot of these and other BMW's of this era had a dealer fit alarm (2T, 3G etc) and the more sophisticated versions had a connection to the ECU (DME). This was generally BMW's that didn't have remote locking on the key but not always as I had 8 Series etc with the three button key and a BMW alarm.

EWS3D was fitted from late 1998 (1999 model year) - that's when BMW started adding E46 style electronics. The rolling code was EWS3 and variants, 3.2, 3.3 and 3D. EWS3 arrived in 1997 for the E38 and E39 and the didn't have a separate EWS module but had everything done by the ECU itself.

So - I'd be replacing the crank sensor first as well as looking around for signs of an alarm/immobiliser.

 

[Steve C]

Afternoon Andy
Car does have the dealer fitted alarm with the separate 2 button key fob.
Seems to work fine with locking and unlocking and siren sounds when activated.
From the gumph I've read, high signal = bad, Low signal = good.
Would a low signal be 0 volts?

Crank sensor has been changed so this can be ruled out.

 

[t-tony]

Where did you source the crank sensor and how much was it? It is not uncommon for very cheap items to sometimes be faulty from new.

Tony.

 

[Andyboy]

I've never bought one for a BMW but I'd only use Bosch. From memory they're 100 quid from BMW.

 

[Andyboy]

Afternoon Andy
Car does have the dealer fitted alarm with the separate 2 button key fob.
Seems to work fine with locking and unlocking and siren sounds when activated.
From the gumph I've read, high signal = bad, Low signal = good.
Would a low signal be 0 volts?

Crank sensor has been changed so this can be ruled out.

OK. Reading the BMW alarm fitting manuals, cars with EWSII don't have any immobiliser wires connected. If you can find the control unit (probably behind glovebox) would disconnecting it do anything? Try disconnecting the body control module as well. Be aware that there is both a DME relay in the fuse box AND an unloader relay which on the E36 is under the dash. This powers (from the green wire on the ignition switch along with green wire terminal 56 on the ECU) the coils (green wire from relay), the fuel pump relay (red 30 on fuel pump relay).

The unloader relay is one of the pale green ones with four wires, green, red, green and brown.

The ECU's driveaway signal is at terminal 10 (green or black/purple).

EWS has three fuses in the front box, 28, 31 and 45.

Do you have an EWSII diagram? If not I'll dig one out.

 

[Andyboy]

Unloader relay under the bonnet on the Z3 apparently:

BMW Z3 Fuel Injection DME Relay Testing | 1996-2002 | Pelican Parts DIY Maintenance Article

A faulty DME (Digital Motor Electronics) relay can cause poor engine performance and hard starting problems. Test it and replace it as necessary to restore your engine's performance.

www.pelicanparts.com

 

[Steve C]

OK. So still having trouble getting this running.
Been having to walk to work for the past 5 months and with the weather turning, really want to get this on the road.
I can't believe that a problem like this is so elusive that it won't show on INPA
The only thing that can't be read by INPA is the dash but don't think a fault here could cause the non-start.
This may be due to using USB and not serial ADS
Does anyone have a Foxwell 530 they can loan? I believe this is a true ADS and may pick up something thats being missed.

 

[mrscalex]

I know you're getting desperate but I think that's unlikely to be a consideration.

Have you pulled the DME to check that none of the pins are corroded. Don't underestimate the impact this could have. I've personally experienced a car where the engine had a hole punched in the sump caused by a corroded cylinder firing pin. In other words the rest of the setup could be fine but if the electrical signals aren't getting in and out of the DME you are stuffed.

I'm not sure you said whether you replaced the crack sensor with a decent make? A crappy make has a significant chance of not working even from new.

 

[Steve C]

Morning.

The crank sensor was not cheap but possibly not a Bosch or OEM

I think the fault is showing before any cranking occurs as the fuel does not prime at ignition on.
Everything has been checked on this and can even be operated with INPA
Fuel pump was a bit dodgy before but has now been replaced.

DME has been in and out several times and all looks clean.
Would a switch/contact cleaner be advised here?

Looks likely that I may need to spend next weekend locked in the garage testing all input/output wires to the DME.

 

[mrscalex]

In may case the pins were obviously corroded. But unless you've examined each pin individually as opposed to having a quick look I'd be tempted to do it again. If they look okay I would say they probably are okay.

I have a second-hand known good crank sensor if you did want to swap it out in case. Also a coil pack if you haven't done that.

This whole area is one I've known and researched pretty well in the past but a) not done anything with it for a year or so now b) it's always been on M54s.

The best advice I can give is to leave the car alone. And google, google and google again. Filling your head with as much theory as possible about the sequence of events, how to confirm each is happening and to discover the experience of others. With all due respect to the good folk of this forum there are usually other forums that are better for this sort of electrical detail.

In other words I would suggest a bottom to top approach based on this theory. Rather than just working through a checklist of common issues.

I once spent about 40 hours across 2 weeks understanding how the EWS (immobiliser) works as I had a very strange issue with no cranking. It turned out the immobiliser logic was working perfectly but the onboard relay had seized. There's no way I'd have worked that out or known how to flash up a replacement unless I'd done all that theory.

 

[mrscalex]

And if your fuel isn't priming before cranking I would use that as your biggest clue. I think it's likely to be very significant.

But don't assume it's a fuel system fault. The DME could be determining something downstream is faulty and preventing the priming for safety reasons.

 

[Steve C]

Thanks mrscalex

Your help is very much appreciated.
I would have given up ages ago if it wasn't for these forums and spent loads more if my bank balance could've coped.

I have spent quite a lot of time searching the web. Just need to filter out all the crap that sometimes gets written.

 

[mrscalex]

I have spent quite a lot of time searching the web. Just need to filter out all the crap that sometimes gets written.

That I agree very much with. Discussions on areas with scant knowledge are usually filled up to a signifcant degree wih speculation, misunderstanding and plan bullsh*t. I'm afraid you have to develop a 6th sense - eg learn which forum members are knowledgeable and reliable, once you have a workable theory try and validate it with a second source. I'd say 95% of material on this type of discussion is not useable. You're looking for the 5% which is and it's hard work to find it. Rest assured the anwer will be out there. You just need to find it. You are surely not the first person to have this issue. And these cars are relatively simple at the end of the day - there will most likely be a relatively simple fix. I'll put my house on that belief.

Try and think laterally too how you may find it. Instead of searching for 1.9/M44 search for the BMW internal designation of the DME, MSE 43 or whatever it is for your engine.

 

[NZ00Z3]

Maybe its time to seek advice from over seas. I do it all the time.

Register on the Bimmerforums Z3 page http://www.bimmerforums.com/forum/forumdisplay.php?137-Z3-(E36-7-E36-8)

Start a private message with user "328 Power 04". Abe is the local guru for all things INPA and DME/EWS related on that site. He can help sort out your serial/ADS INPA if needed.

 

[Steve C]

Just a little update if anyone is following.

The output from the DME to earth the fuel relay shows 5.6v when ignition is turned on.
Surely this cannot be correct?
Should it not be just earth the relay?
When activated with INPA it works fine.

 

[NZ00Z3]

Hi Steve

Its a rainy spring Sunday morning here with very little to do, so I'm doing a deep dive into the research for your problem.

Key question. What is the build date for your car?

You say in post #1 that it is an early 98 car. Is that the build date or date of first registration. The reason why I ask it that I have several sets of wiring diagrams that cover 1997 to 1998 period and I want to make sure that I'm using the right ones.

 

[Steve C]

Hello Murray

RealOem states November 97 so registered 98
Any help would be most welcome.
Thanks

 

[NZ00Z3]

Hi Steve

I was using the 2008 (doh) 1998 Great Britain wiring diagrams from here https://zroadster.org/resources/1998-z3-z3m-electrical-troubleshooting-manual-for-great-britain.41/

Just had to check my thinking with the North American 9/97 to 9/98 drawings as you car is a 11/97 build date from here https://zroadster.org/resources/1998-z3-z3m-electrical-troubleshooting-manual.5/

Both sets of drawings show the same thing. I will be referencing the North American drawings from here on in.

EWS2
I worked through the drawings from the EWS. I also have the EWS document, which has been helpful. If you look at the first page of the EWS 2 section (page 7), there is a picture of the things that connect to the EWS. BMW uses a standard convention in its drawings. The items on the left side are inputs to the EWS and the things on the right side are outputs from the EWS. Through the drawings, I have established that the Z3 EWS2 does not have a connection to the Board Computer (BC) or the GR1 (what ever that is?). The document states that if the key transponder is correct, that the EWS releases both the crank relay and the ISN to the DME at the same time. Your car cranks, so that step has been achieved.

The only twist that could come via the EWS is the "Double Lock" signal coming in on pin 8 in the EWS from the ZKE4. If this signal is high (12 V DC) when the EWS determines that the Crank relay can be enabled, the EWS should send an unlock signal to the ZKE4 to unlock the double lock. It is not documented if the double lock input signal impacts on the release of the ISN to the DME. Looking here for any reason for the EWS to not enable the ISN signal. I suggest that you test this out. With the key in position two (run), test to see if there is 12 V DC on the EWS pins 8 and 14. Pin 8 should be the double lock input and pin 14 should be the unlock output. I say should be as its really difficult to differentiate between the two in the drawings and connector pin outs. The above is my best guess of the allocation after changing my mind many times. Both pin 8 and pin 14 should be 0 V DC. If pin 8 is 12 V DC and stays there, then you may have found your problem, as it is labeled as coming from ZKE4, output, Vehicle immobilisation, connector X10182 pin 15.

I looked into the ZKE4 on my 2000 Z3 with my Foxwell NT530. Under "Central Locking" there was a "Central Lock ZS" indicator. Mine was "No". Have a look to see if your is "Yes". This may tie in with the Double Lock line of thought.

There is a scanning program called "BMW Scanner 1.4". I don't have it nor have I used it. But I know that it has a page that looks to see if the EWS inputs are enabled and if the outputs are enabled. I may be a good solution to see if the ISN has been enabled.


I don't have an EWS2 to play with. I have looked into the EWS3D on my car with my Foxwell NT530. In the "Internal" section there where several lines of relevant information:
- Key is sending = Yes. I take it that the key has been seen and recongised by the EWS
- DME line switched free = Yes. I take it that the ISN has been sent and the DME has been enabled.
- Starter switched off because of:
* Reached Resolutions limit = no
* PN/ US clutch switch = no
* Central locking closed = no.
* BC = no

Are there similar indications in your EWS2?

I looked at the "Central locking closed = no" and went and got my spare key. With the ignition in position 2 so that the scanner would work, I could not remotely lock the car. I concluded that the ZKE4 and EWS was working correctly.

DME 5.2
I then went to the DME and worked back towards the EWS. I suspect that the Main DME Relay (engine control relay) K6300 is not being called to operate. This relay controls lots of key engine components like the injectors, ignition (spark) and the full pump. See drawing 1210.20-00. This drawing shows the relay. In the bottom right corner of the drawing there is an arrow head with the letter "D" in it. Click on the number in the green square below it to jump to drawing 1210.20-02. You will see that the "D" in the arrow head provides 12 V DC to fuse 13, which feeds the fuel pump relay. So an easy way to test that the Main DME Relay has operated is to see if there is power to fuse 13. You have said that the fuel pump can be run by turning it on with INPA. This requires two outputs from the DME to close, Pin 27 for the Maine DME Relay and pin 63 for the fuel pump. So, the Main DME Relay and fuel pump works when it it told to by the DME through INPA. So, why are they not being called to operate for a normal start???

If you have power at Fuse 13, then the DME is seeing a enabled ISN line on X6000 pin 10. The question becomes, why is the DME not enabling the fuel pump on X6000 pin 63?

If you do not have power at fuse 13, it looks like the DME is not seeing an enabled ISN line.

I don't have a DME 5.2 to play with. I have looked into the MS42 on my car with my scanner. There were no digital inputs or anything else that showed that the ISN or Main DME Relay had been enabled. Have a look in your DME, there may be something different as yours is made by Bosh and mine is made by Siemens.

Have you checked the ISN enable wire from EWS connector X1659 pin 4 to the DME connector X6000 pin 10, both for continuity and for a lack of a connection to earth?

If that all checks out, then it gets difficult for the home DIY. I would grab an oscilloscope and back probe the pin 4 on the EWS to see the ISN signal being sent to the DME. Then back probe pin 10 on the DME to check that the signal is being received. Then would come the continuing question of "Is the EWS and DME aligned with the same ISN?"

INPA
Your car has a 11/97 build date. The full change over to OBD2 occurred on 3/98 for non M Z3's. Before then, there was a mix of OBD2 and ADS modules in the Z3. I'm really surprised that you have got as far into the EWS as you have. Hopefully you can read the ZKE4 as well. All Z3 DME's are OBD2.

The output from the DME to earth the fuel relay shows 5.6v when ignition is turned on.

I take it that this is 5.6V DC from X6000 pin 63 to earth? Does Fuse 13 have 12 V?

In a good old relay logic world, with 12 V at Fuse 13, you would see 12 V to earth at pin 63 when the relay contacts inside pin 63 where open. You would see 0 V to earth when the relay contact inside pin 63 closed and energised the fuel pump relay. This is because the full 12 V is being used to power the fuel pump relay.

But, pin 63 this is an electronic output in the DME. If you have 12 V at Fuse 13, then I would suggest that the DME pin 63 electronics are providing a resistive connection to earth. There would be say 7 V volts drop across the fuel pump relay and 5.6 V volt drop across the resistive connection of pin 63. Total volt drop of 12.6 V. Most relays have a pick-up voltage of around 80% of rated voltage, which is around 10 V for the fuel pump relay.

Well, that's my day cut. It's 4:40 pm here, the sun has come out and its time for a beer in the garden. Good luck with your investigations, testing and repairs. Hope this has been of help.

Regards

Murray

 

[mrscalex]

You're a lucky man @Steve C . This is fantastic advice from @Murray Wall and would have taken I expect many hours to put together. This is the sort of deep dive I would do for a problem so appreciate what he's gone into here. Well done Murray.