Complete loss of power

[JoeGons]

I have a BMW 520i 1995
M50 engine
WBAHB620X0BG94472

I am having some trouble and I might need my DME checked.
It is a European type.
Siemens MS40.1 not a BOSCH.
Good place in the UK?
The problem came on over a period of months and just got worse.
I was driving it and the gears were shifting as normal.
I took it to my man (BMW Trained) and he did the injectors, changed the plugs, plug coils, changed the fuel filter and checked fuel pressure , Mass Air Flow etc.
At this point, he has checked every thing and every sensor.
The problem only got worse because I drove it to his place and now it is stuck there.
The car is starting and does not show any codes that would cause the problem I have.
It did have a Cam Position Sensor Code, 132 I believe, but the sensor has been replaced.
There are no fault codes now.
I did have an “Air Temp” sensor fault code for a long time that never gave any problems but even that has gone away.
It idles just fine but will not accelerate and has no power.
It is not drivable.
If I try to drive it, when I try to move off it just does not want to move.
It will move but very slowly and if you persist, you can get it out of the garage.
One interesting detail; My Indie tells me that sometimes the scanner looses connection with the DME but there is no "Communication" code coming up.
Siemens MS40.1 # 1 12 14 1 429 440
5WK9 003/1

Please tell me that I only need to put in some Gas!!!

Joe banghead

[Tiger]

If you haven't changed the crank position sensor... this is what I would do first. Buy only OE crank position sensor.

[JoeGons]

Thanks,
I'll have that done.

[shogun]

My Indie tells me that sometimes the scanner looses connection with the DME

depends on his scanner. Probably he does not have a original BMW diagnosis system. I just got a GT1 scanner for BMW cars from a chinese seller, also this one sometimes does not communicate with the car, then I try various ways to overcome that, yesterday for example I had the scanner connected to the diagnosis port, no communication, then I left it connected and switched several times the ignition key back to off, acc and on, and suddenly it communicated again with the system.
Still playing with that tool to learn, so I could make a test simulation of the wiper pressure motor, central locking, IHKA testing, engine codes etc.

[JoeGons]

Thanks for that.
I'll pass it on.
Gives me hope for the DME

[genphreak]

x2 for the CPS.

Other things may be:

Bad transmission (if auto). The Transmission computer talks to the ECU and can cause strange results in addition to a bad battery. Verify the battery is not too old, they can become start to intermittently drop voltage which can upset ECUs and cause all kind of codes/ errors.

If so, the car won't start one morning. Replacing it with a known good one can solve all kind of annoyances...

[JoeGons]

Hmmm

It is Auto but the problem remains in "Park".

There are no codes showing up.

[shogun]

Did you already check the bowden cable from the shift stick to the automatic transmission. Maybe it slipped?
Here you can see what I mean, that is an E32 740, but same tech details
E32 Selector Shaft Seal Replacement (http://bmwe32.masscom.net/dutch740/selectorshaft/selectorshaft.htm)
Also clean the switch page_2 (http://www.nmia.com/~dgnrg/page_13.htm)
do you see all the gears in the cluster check control?

For used parts you might ask in the U.K. forum
The 7 Series Register Homepage (http://the7seriesregister.co.uk/)
that is mainly for the 7-series, but some people also have E34.

[JoeGons]

Thanks,
I did not mean the Trans is stuck in park.
I mean the power problem is there when the Trans is in park. The Trans is working just fine.

[JoeGons]

Update:
First a recap.
When the transmission is in neutral, (park) and you apply a rapid increase in throttle, the engine “bogs down” and really misbehaves.
If you apply small and increasing throttle, the engine will accelerate.
If you put it in drive and try to move off, it just “bogs down” and goes nowhere.
It will stall if you persist.
It will restart right away.

My mechanic, Kennard, and I have put our combined heads together (that includes you) and we are moving forward.

We have checked the Air Flow Sensor.
Tried two new ones.
Even tried mine on another car.
We have checked the TPS with meter and scanner. It’s fine.
We have changed the Cam Sensor. Fault Code gone.
The fuel pressure is fine.
The fuel pressure regulator is working.
The backpressure is fine.
The Transmission is fine.
The injectors are working fine and show normal response on the scanner.
The O2 sensor was checked. (Not that this would cause such a big problem.)

There is one thing we are concerned about.
The ignition timing is not responding the way it should when you attempt to accelerate or increase the RPM and is inconsistent. (Kennard’s words)
NO CODES!
The Crankshaft Sensor is next.
Of note is that the tachometer is working as normal with no erratic behavior.
We have a Crankshaft Sensor standing by and will be checking the CRANK sensor with an oscilloscope on Monday.
As a last resort, we have a DME standing by.

Now for something to keep you all interested.
Like so many E34’s, I have a battery drain.
To save the battery, I have installed a relay to disconnect the battery.
I’ve killed several (expensive) batteries.
I use this when I will not be using the car for more than a few days.
You know that there is a “learning” process that the Computer goes through to adapt to your style of driving.
My understanding is that this is more to do with the transmission.
Kennard is a little concerned that the frequent disconnection of the battery and resetting of the computers might be causing a problem.
Any thoughts?

I will update as time permits.
Joe

[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 (http://www.bimmerfest.com/forums/showthread.php?t=536505)
---------------------------------------
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 (http://www.bimmerfest.com/forums/showthread.php?t=586735)

--------------------------
EWS bypass for performance chip (http://forums.bimmerforums.com/forum/showthread.php?1238809-EWS-bypass-for-performance-chip)

or search for: BMW EWS2, EWS3.2 EMULATOR E34, E36, E38, E39, E46
http://news.excheap.com/wp-content/uploads/2011/04/bmw-ews-immo-emulator-user-manual.pdf


Schematic of the EWS-II system:
EWS Deletion Chip - Technical Domain (http://qcwo.com/technicaldomain/ews-deletion-chip)
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-content/uploads/2008/12/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-content/uploads/2008/12/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 (http://www.racingchips.net)) 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-content/uploads/2009/03/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-content/uploads/2008/12/image-35.jpg

Installing a chip in the DME Installing a Chip on the 1993-1995 BMW 325i/525i - Technical Domain (http://qcwo.com/technicaldomain/installing-a-chip-on-the-1993-1995-bmw-325i525i)

[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.

[whiskychaser]

Anyone help with the harness is most welcome.
You may be able to get hold of a loom on ebay UK or DE. Can your mechanic's scanner read live data? Your issue may not be causing a fault code but the data may be helpful in diagnosing the problem. I use GT1/DIS as Shogun mentioned. My interface came from the US in kit form and I have absolutely no problems with stability. I used carsoft type interfaces previously and also suffered with connection problems, particularly if the engine was started during diagnosis.

[JoeGons]

Thanks.
I have my eye on Ebay for a Siemens compatible harness.
I do believe he has live data. In fact, he told me that there were a few odd things going on.
He said that the pulse width of the injectors was not as it should be.
He had previously tried a different fuel rail to see if it was due to bad injectors.
Also, blocking the fuel return at the rail and allowing the fuel pressure to go up to 90 psi did produce a temporary solution.
The problem is with the fuel delivery to the engine that is not enough.
Simulating a very cold condition seems to get the computer to give enough fuel but it is not a fix.

Joe

[whiskychaser]

Not sure doubling the fuel pressure is a great idea :-) As I understand it, the MAF meters the air. It passes on what it finds to the ECU which controls how long the injectors open. The O2 sensor doesn't come into play until the engine is warm. It still needs sorting but you may be able to rule that out for the moment. Maybe have a look at the MAF readings and see if you can find a bench mark for comparison? Does it run better with the MAF disconnected and then die when you plug it back in?

[JoeGons]

LOL Thanks. rotfl

The fuel pressure thing was just to see what would happen.

It does not seem to make a lot of difference if we disconnect the MAF. Not the same but it will run.
Tried a different MAF also. In any event, the readings from the MAF seem to be in the normal range.
It is my understanding that the O2 sensor comes into play when IT is up to temp. I understand that the heater in the O2 sensor is designed to activate the sensor as soon as possible. (Whatever that means)
The puzzle is that there are no fault codes and all the sensors seem to be within normal range, hence no fault codes.
That has led to the belief that there is something that is causing the computer NOT to process the signals from all or some or one of the sensors.
Perhaps there is a ground wire somewhere on the harness that is faulty.

Joe

[whiskychaser]

LOL Thanks. rotfl

The fuel pressure thing was just to see what would happen.

It does not seem to make a lot of difference if we disconnect the MAF. Not the same but it will run.
Tried a different MAF also. In any event, the readings from the MAF seem to be in the normal range.
It is my understanding that the O2 sensor comes into play when IT is up to temp. I understand that the heater in the O2 sensor is designed to activate the sensor as soon as possible. (Whatever that means)
The puzzle is that there are no fault codes and all the sensors seem to be within normal range, hence no fault codes.
That has led to the belief that there is something that is causing the computer NOT to process the signals from all or some or one of the sensors.
Perhaps there is a ground wire somewhere on the harness that is faulty.

Joe
If the coolant temp is not high enough, the ECU will disregard the O2 sensor input. Wiring a fixed resistor into the coolant temp circuit is going to make the ECU think the engine is cold all the time. Having to do that suggests you have unmetered air getting in there. I can only assume you have checked all your hoses but have you tried a smoke test?

[JoeGons]

Thanks.
I do not believe Ken has done a smoke test.
I do know he was checking for leaks.
I have ordered a new MAF and will try that but I really don't have my hopes up.
I have a new O2 sensor.
I think the simulated temperature is extremely low and that keeps the ECU in some sort of default mode.
That still does not cause a fault code.
Whatever it is, I think that the injector pulse width must be affected by that.
Time to go back to the beginning and have another look at what's in front of us.


Joe

[whiskychaser]

You have probably read Mordan's thread about his quest to solve the problem with his 520i and Siemens DME? If not, it is worth a look. IIRC, he says the coolant temp sensor has a resistance of about 7K for 6 deg C going down to 2-300 ohms when the engine is at operating temp. Depending on the resistor value you inserted, you could be telling the DME that the engine is always stone cold. That will lengthen the amount of time the injectors open. Logically, you would only have to do that to balance the mixture if the amount of air coming in were wrong. I don't have the air flow figures for the M50 2.0. The nearest I can get is an M54 2.2 :-) If you can find the spec or use a smoke test you can at least cross this off the list

[JoeGons]

I don't recall the Mordan's thread.

Basically, I think we are telling it the temperature is the lowest value it can sense. (-40 deg C)
I think Ken put a high value resistor in the circuit.
Not much between that and an open circuit except there is no fault code generated.
Next week I will speak to him and talk about the smoke test.

Joe

[whiskychaser]

I thought Mordan's thread was here but it isn't. Link is here:
http://forums.bimmerforums.com/forum/showthread.php?1590946-M50-sensor-problems-need-some-wizardly-help

Hope you get it sorted finally

[JoeGons]

thanks

[JoeGons]

Mordan is lucky.
He got it fixed in three months.
I've been fighting with this SOB for over a year.

[alex 1993 525i auto]

Hi,

I had a similar behaviour with my car last year. It turned out to be the timing was off because of a mess after nuts went off from the stop plate of the intake cam gear. My car was not slipping like yours apparently.

http://www.bimmernut.com/forum/showthread.php/44460-Low-power-at-low-rpm-(below-2200-rpm-or-so)?highlight=alex+1993+525i+auto

Mine was having a hard time starting when cold (less than 0c or 32F or so) and was lacking power below 2500 rpm. Idle was fine.

Also what about your transmission, maybe I missed it?

Good

[JoeGons]

Thanks.
As a reminder, the problem.
The engine starts and idles.
It's when you try to move that there is no power and the engine bogs down.
The car will not move.
If you "floor it", it dies.
It will start up right away but still no power.
Just thinking:
It seems to me that if I have a slight vacuum leak, it might be hard to start and it might idle rough. Hesitation when moving off but should be able to drive.
If I have a large vacuum leak, it should be really hard to start and might not even idle.
We're not talking about a rough idle or a miss or a little hesitation.
We're talking about not being able to move off.
Now:
When we fool the computer that it is really really cold, it is drivable.

What does that tell us?
For one, at that temp, the computer will ignore several sensors.
However it seems to me that the Crank position and possibly the Cam position can be considered functional.
Perhaps, the throttle position also.
It idles just fine so I feel the idle control must be working.
If there was a slight Vacuum leak, the extra fuel might hide that,
A large vacuum leak should still cause a problem at idle.

I will be speaking with Ken today and we'll map out our next step.

Thanks

[JoeGons]

Well folks,
We’re almost there.
Ken pulled the engine harness apart and checked it.
He double-checked all the sensors.
BTW he did check for intake leaks. The vacuum etc is just fine.
With the new DME installed:
He then removed the resistor from the engine temp circuit and fired it up.
Well he tells me that there is some hesitation and misfiring but it is drivable.
He also notes that when the MAF is disconnected, it runs even better.
Even though the readings from the MAF are in the normal range, he suspects that it is not quite right.
I have a MAF on its way and we expect that when that is installed, all will be well.

Later

Joe

[genphreak]

Sounds good.

Note that a common fault with all EFI ECUs is the output transistors that control the injectors and/or the spark. Mostly spark- these are the biggest and change temperature the most. They sink heat to the casing, so are screwed to it and stuck with silicone compound. When they go, they usually go when hot only- this means stumbling above a certain rev range, I've seen 2500-3500 being the common range. Usually it is only one or two transistors, but replacing all is worthwhile. Most change the ECU- but availability is the key here perhaps.

Often (not always) the transistor that is causing the problem is browned a bit or smoked (cracked and burnt)- so easy to see once you pry apart the ECU boards.

Note: All this is based on exp with Bosch ECUs, sorry.

[JoeGons]

Thanks
The problem is that the Siemens is not really made to come apart.
It requires a lot of work and is best done by someone with experience.

[genphreak]

Thanks
The problem is that the Siemens is not really made to come apart.
It requires a lot of work and is best done by someone with experience.

No worries.

BTW: For those unfamiliar with these issues, when the transistors fail intermittently, they usually cause stumbling problems after heating up. That happens on time from startup, revs and will happen more quickly on a hot day or when left in the sun.

[JoeGons]

New MAF and Ken is happy.

The moral of the story?
New DME and all new sensors will fix all your problems.

Problem solved.



Thanks to all.

[632 Regal]

Long project, great success!

[JoeGons]

Thanks again for all the help on the Forum that kept me focused.