Complete loss of power

[genphreak]

1. The Engine ECU learns too, to adjust timing and injector duration
2. Definitely try plugging in a new ECU, they can suffer from blown outputs causing timing/intermittent/poor control of injector and spark. Just make sure t has the same part number (check the online parts catalogue for later production units, any of them listed will work. Not sure if the 520 is common to 525 too, may be... but may just have a different ROM chip. You need one from the same market (EU/Japan/USA etc.) so check by VIN number...

[JoeGons]

Well, there is some improvement.
The Crank sensor was changed and seemed to help for about ten minutes.
Now the real tear down started.
There seems to be a problem with the O2 sensor circuit.
Even though the O2 sensor output readings are looking OK, there still seems to be a problem there.
The Computer might have suffered some damage in the O2 circuit and does not seem to be processing the signal from the O2 sensor.
There is also a problem with the engine temperature sensor.
The sensor resistance seems to be within specs but the computer does not like it.
A resistor was put in the circuit to change the value and that seems to have more or less resolved the complete lack of power.
My guy thinks the computer was sensing a very hot engine and messing up the fuel regulation.
With the O2 sensor disconnected and the resistor in series on the Temp circuit, the car is drivable but is not idling quite right. And of course, the fuel consumption.
He suggests a new DME computer.
Problem is that it is a Siemens and scarce.
Sent for one.
The trouble is that he is having a hard time getting the scanner to stay connected.
Loss of communication happens quite quickly when you do get communication.
He plugged in a borrowed DME and there was no problem with communication but of course, it would not start.
The next problem will be to get the (ISN ?) codes from the EWS in order to program the new DME.
It seems to me that there must be a way to reprogram the system in the event the DME is completely fried.

Will BMW have the original codes?

Or is there a way to get the ISN code directly from the EWS?

And the beat goes on!!!

Joe

[genphreak]

Siemens ECU? I've never seen one. Have you verified it is the correct unit/same one the car was built with? There are usually several part numbers (remanufactured/upgraded and new replacements) that fit each production model. I am sure a Bosch ECU/ECM would work fine.

The engine wiring in all e30, e31, e32, e34 and e36 is pretty much the same- just with additional sensors in the later cars- so long as you don't take an ECU from an engine model across looms you are ok. But even then, you can do this within reason or with small modification.

Only EWS systems on the later cars can cause trouble when you swap the ECU, if you have trouble with this you can simply buy a performance chip from someone like Mark D'Sylva (EAT chip). If you send him your original chip, he can extract the EWS code and burn it into the new chip he sends you back.

The resistor in your temp sensor circuit seems strange- very. Can sometimes be hard to tell if it is factory or not, but easy to see at times. Are you sure it was not on the (12V) power line to one of the sensors?

Your mechanic, if he is having problems communicating with the car diagnostics, is using some form of dodgy communication software/interface- The L line used on e34 is typically only stable with the original BMW hardware and software combination. The problem is that people expect it to work as they find it happens on most cars (eg the universal plug and play they encounter on OBDII equipped vehicles)

[JoeGons]

Thanks gen,

Yep, Siemens not Bosch.
DME ECU Control Unit

RMFD
Programmed DME from 1/95
Suppliment S199A=NO MS40.1
12 14 1 429 440
Old part number: 12 14 1 744 923
That means: Programed without S199A
Programed for Cat.
------
My DME:
DME MS40.1 12 14 1 429 440 12141429440

Siemens MS40.1 5WK9 003/1

Siemens 5WK90031

That means: Programed without S199A
Programed for Cat.

Same as: 1 748 120, 1 744 597


Tried a borrowed DME and no start.

Getting voltage OK.

True. Communication with non BMW OE kit can be difficult.
Communication good with borrowed DME.
We just need the code to put in.
Need to get the code from the EWS.
The mechanic told me he might need to retrieve the code one digit at a time.
He is not equiped to pull it off the chip.
Mark D'Sylva (EAT chip)? Wonder if that will work with a Siemens.


Joe

[shogun]

I googled a bit with 'BMW E34 EWS delete' and a lot of info comes up like this

EWS Delete / Bypass and no-start problem finally solved - VERY LONG read
EWS Delete / Bypass and no-start problem finally solved - VERY LONG read - Bimmerfest - BMW Forums
---------------------------------------
EWS II problem solved for a 1995 525i

Hello everyone! As some of you know, I have been having major issues with my 1995 525i regarding the EWS II imobilizer system. It is now repaired!

Here is my story... My wife got stranded with a sheared ignition steering lock. She could not unlock the steering wheel to start the car. In order for me to get the car home, the only choice I had was to have it towed on a flat bed. Now the dilemma was my driveway, which is very steep. My only choice was to leave it at the curb. My next problem was to get the ignition tumbler out. Thanks to BMR_LVR ( Steve ), I finally got it out and unlocked the steering. I got her started and put her in the garage. Unfortunately the EWS II detected a theft and shot my DME down .... So now my choices were: #1 Get a red label DME like Steve did or #2 Purchase a EWS Delete chip with a stage one upgrade (gain 15 to 20 H.P., add 200 more RPM red line ... oh and remove the controlled top speed shut down.)

I choose the chip. My reasoning was that I knew my silver label DME was good. The following is what I did to make this $65 ebay chip work. First, I checked all my relays and assured they were in good working order. Next, located my EWS II module (it is on the driver side with a big yellow plug under the knee bolster), then I bridged wires 1 & 3 together. This is my ignition switch that sends power to the starter. Each wire is black with yellow. Next, at the engine bay, next to the diagnostic port, is the wiring harness. I clipped the # 7 wire (This wire is the one that sends the signal to pin #66 on the DME side letting it know that the EWSII is active). So by cutting the #7 wire earlier, the EWS II is not sending a signal. I then installed the EWS II delete chip and connected the battery. VIOLA! She is running and purring again and no more faulty EWS II system.

Just want to add that the EWS II delete chip with stage 1 upgrade works really well. I feel the extra power and smoothness of accelaration. I hope this helps someone in the future Noel
Vendor is 2poole4u on ebay ! ( EWS II Delete chip /w stage 1 upgrade $55 + shipping ! excelent service and prompt delivery

EWS II problem solved for a 1995 525i - Bimmerfest - BMW Forums

--------------------------
EWS bypass for performance chip

or search for: BMW EWS2, EWS3.2 EMULATOR E34, E36, E38, E39, E46
http://news.excheap.com/wp-content/u...ser-manual.pdf


Schematic of the EWS-II system:
EWS Deletion Chip - Technical Domain
In the 1995 325i / 525i, it is used the EWS-II. Those cars have module (EWS Control Module), pictured above as “EWS II”, that connects to the ecu (“DME” above). The car key sends an unique code through the key lock cylinder, to the transmitter/receiver module which amplifies the signal and convert it to a digital signal and then send it to the EWS control module. This module will compare the received code with the code stored in the ecu (“DME”) and if the same, all normal functioning is resumed. Otherwise, the starter might work or not, but there will absolutely be no injection.
http://qcwo.com/technicaldomain/wp-c...2/image-32.jpg

In short, your car can only be started with your key (transponder key). The key has a micro chip inside with the unique code stored on its micro circuit. Your car’s ecu will only “listen” to your key. A perfect copy of the key won’t work either, even if it is a similar transponder key, originally made by BMW.
http://qcwo.com/technicaldomain/wp-c...2/image-34.jpg
So an EWS delete chip, has as part of its functions, the disabling of this system. We don’t have one of those chips available, but the one we have (RacingChips : OtherDeal.com, Automotive Electronics Car Computers ECU ECM Racing Chips Diagrams Service Software) can be used if some wiring tampering is done. Our chip is meant for Non-EWS ecus (0 261 200 413 with RED label or sticker, NOT Silver colored). If our chip is used without the tampering on EWS enabled ecus (silver label or sticker), the car won’t crank or will crank but will not start.

You can install the Non-EWS chip and manually disable the EWS system by locating the EWS Control Module (location pictured below) and cut or disconnect the wire #4 (solid green colored). This will allow the chip to give its power and not been interrupted by the EWS system.

Other alternative, is to disconnect the same wire from the ecu instead. On the ecu it connects to pin #66, as shown on the image below. The image is of the harness terminal and NOT of the ecu terminal. That is why numbers are on inverted order. Click on it to see it full size
http://qcwo.com/technicaldomain/wp-c...3/image-43.jpg
The cons of this are of course, that your car will no longer be protected by the EWS system as long as you have this modification.

Reaching the EWS Control Module:
http://qcwo.com/technicaldomain/wp-c...2/image-35.jpg

Installing a chip in the DME Installing a Chip on the 1993-1995 BMW 325i/525i - Technical Domain

[genphreak]

Its an old hack indeed. I have one of these chips for an M50B25, but am yet to hack any of my cars wiring (EWS II @1995) to install one.

A quick word of warning though, anyone following those instructions should verify what each one of the wires described in those instructions actually does against the exact wiring diagram for their car, else they may find a market/model/run wiring variance could see an extraordinary and unexpected outcome and further problems.

[JoeGons]

Update:
Well the problem goes on.
I got a new DME and the problem remains the same.
Sensor readings at the sensor and at the DME end are normal. There are still no fault codes.

I am now looking for a complete engine harness/loom.
The thinking is that there might be a problem with the harness that is causing the problem.
BMW E34 520i Auto Trans using the Siemens system.
Siemens DME. Siemens sensors.
VIN: BG 94472
NOT a Bosch DME.

[632 Regal]

I am now looking for a complete engine harness/loom.
The thinking is that there might be a problem with the harness that is causing the problem.
BMW E34 520i Auto Trans using the Siemens system.
Siemens DME. Siemens sensors.
VIN: BG 94472
NOT a Bosch DME.

Just saw this thread, I think you are on the right course. When it comes to stupid stuff I can't figure out it is staring me in the face.

I had a Huge problem with my 850 until I cut the immobilizer wire. possibly look into the OBC settings, could be by default it's limiting the engine? (valet setting?) Specially you indicating you have a battery cut off relay. My immobilizer had a mind of it's own and had to finally cut the umbilical cord to fix it. Took me 3 months to figure that it was the problem, jumping through hoops to come to that conclusion. Cutting the cord was the last thing I did and then everything was fine.

[JoeGons]

Hi,
Thanks for this.
The one thing we have not tried is by-passing the cutoff relay at the battery.
The suspicion is that there is a problem with a ground somewhere.
My indie thinks it might be one of the grounds that the DME needs that is not directly going to a sensor.
He has checked all the sensors and all is well there.
That is why he is now looking at the harness.
I have read many times that these cars are very fussy when it comes to the battery voltage.
I will pass this on to him and have him check it.
What he is doing now is "fooling" the ECU by simulating a very "cold" condition.
That makes it drivable but he knows it's not a "fix".
We've been working on this for over a year.

I still want to find a harness that is compatible with the Siemens DME.
It will have to be from a Euro car. The US cars use a Bosch DME. (except a few odd 320i)

Joe

[JoeGons]

Anyone help with the harness is most welcome.