M70 motronic 1.7 MOSFET reference needed

[pchotard]

Hi

I got an issue on one of the DME motronic 1.7 of my 1991 E31 M70.
Smoke was going out from one of the DME and also the corresponding coil was smoking.....

I have open the DME, found a burned MOSFET, but i was not able to find the reference of this components on the web.
I suppose it was a internal BOSCH reference. Does someone know a compatible MOSFET reference i can use ?

Attachment 681135Attachment 681136Attachment 681137

Thanks

[rjjablo]

https://www.ebay.fr/itm/BMW-E32-750i...8/131673528017

[TxGR8White]

Bad coils will do that.

[pchotard]

https://www.ebay.fr/itm/BMW-E32-750i...8/131673528017

@rjjablo Thanks for the link, but i am looking for the MOSFET reference only

- - - Updated - - -

Bad coils will do that.

Yes i confirm,, the coil is dead.

[cartoonz]

for the replacement for that driver,
Ask EEDegreeToDrive

[Timm]

There's oodles of equivalents - but TIP 162 worked for me:

https://uk.farnell.com/multicomp/tip...295?ost=tip162

...or on Amazon:

https://amzn.to/3f3FGtM

Same as used on the V8's: https://www.meeknet.co.uk/E32/ECU/Index.htm

[pchotard]

Ok thanks for the MOSFET reference Timm.

[pchotard]

Hi

I received the new MOSFET, but its form factor need to be "tuned" to put it back in place inside the DME.

Attachment 681706Attachment 681707

The M70 is now running on 12 cylinders !
Thanks

[Timm]

Well done! Yes, I had to do the same on my M60 - nothing a file won't sort out!

[m6bigdog]

Not that it matters much for you as you have resolved the problem.

But for those that are electronics professionals.
The correct device type is everything in identifying the appropriate substitute device.
See attached document.
The device is not a MOSFET it is a NPN Darlington Power Transistor - SOT-93 package with the heatsink tab removed.

My only suggestion in selecting a substitute is to make sure the back of the device looks the same as many devices have changed the package configuration over the years and the power dissipation ratings can be lower.
I anticipate the original DME device has bare metal exposed on the back side for best heat dissipation to the heat sink.
Some of the newer devices will be completely enclosed in plastic and hence the power rating is compromised.
Also, make sure a heatsink compound is applied to the back of the device in contact with the heatsink.
The heatsink compound substantially increases the heat transfer and thermal dissipation keeping the transistor cooler.

[E31 850i]

hese are special BOSCH transistors.
...buy a cheap DME (E30, E36...) and put that transistor to your DME.

[shogun]

Thread copied from E31 forum for reference in E32 forum for M70 owners, time has come that DME's and EML are at the end of their lifetime. If someone has to add info from his repairs or other sites, please do so, the more info the better.

EML:
'd look at his EML I finally got around to it. He reported the throttle plates were acting funny and one bank wasn't running. There was no obvious damage, but one of the aluminum electrolytic caps didn't look great. We decided to proceed and replace the capacitors.

There were a few general purpose caps in there, but there were also a few 'special' ones, including a Tantalum capacitor, a Philips aluminum can, a Fraco 100uF 10V, and some Roederstein EK sealed/baked capacitors commonly used in the Audio industry.
(There is also about 50 ceramic capacitors and about 100 early surface mount resistors in there too!). I replaced 8 capacitors altogether, cleaned and coated the board, and dropped it in my 1991 850i. It started right up and I took it out for a spin. Everything seems to work fine, cruise, idle, etc. I didn't do any kind of programming or throttle calibration, just took it for a spin. Upon return, I measured the resistance of the old capacitors, (the meter in front of me doesn't measure capacitance) and most floated up to 6M-ohm, except the Fraco, which measured a short circuit, 0.1ohm, perhaps it was the problem?
I replaced most with Panasonic FC series, which were 105C operating temp and low impedance. Interestingly, capacitors have changed enough in 25 years that many were actually smaller that the originals, though no heroic measures needed to be made.

Capacitors Used:
2x Generic 220uF 63V 105C (Replaced with Panasonic FC Series, Newark #49W7101, $0.585/ea)
2x Generic 100uF 25V 105C (Replaced with Panasonic FC Series, Newark #96K9155 $0.147/ea)

ROE 220uF 40V (Popular on Audio forums, Replaced with Panasonic FC Series,220uF 50V, Newark #49W7044 $1.03/ea)
Fraco 1000uF 10V (Replaced with Panasonic FC Series, Newark #25M9148 $0.73/ea)
(EDIT/NOTE: In my diagram lower-right, I labeled the Fraco one 100uF when it's actually a 1000uF; Thanks for noticing Albert850i!)

Philips 220uF 10V Low ESR 105C (Replaced with Panasonic 220uF 16V, OS-CON Series, Low ESR, 0.013ohm, Newark #98W0174 $1.23/ea)
Unknown 200uF 10V Tantalum (Replaced with Vishay 100uF 10V, 150D Series, Axial, Newark #65F2330 $4.57/ea, I also had ordered a KEMET Tantalum #70K8848 @$4.00/ea)

Disclosure: I don't know what's so special about the ROE or Fraco capacitors, but I used pretty decent Panasonic caps that I hope are suitable quality. I also used them in place of the generic caps which is probably overkill.
Also, The Tantalum cap I used is rated 2000hrs@85C and derated to 1000Hrs@125C. The higher temp mil-spec ones were $5-6/ea, out of stock, and had 20pc minimum. Regardless, Assuming 60MPH, that's 120K miles if the capacitor is operating near boiling temperatures. In short, some of these capacitors might not last another 25 years, but should last at least 10!

ALSO NOTE: This was a 0 205 000 004 EML presumably from an Early model 850i. I swapped out my 0 205 000 015 EML with it and it worked fine, but other EMLs may have different parts!
----------------
Originally Posted by Albert850i
Managed to open it, by releasing the locks at both ends and opening the two wide black tabs which keep the sub-connector in position.
I have soldered in 8 new caps, but do not have a tool to check the old ones. Ohm meter shows climbing resistance, probably as the caps are being charged; possibly they were all still OK. Note that your sketch shows a 100 uF - 10V cap on the right hand board, which should be 1000 uF - 10 V.
-------------------------
Thanks for noticing that. Ohm meter climbing is correct for a capacitor.. the time it takes to go open-circuit is proportional to the capacitance, but without a capacitance meter, tough to get an exact figure. If they don't end up open-circuit (or at least in the meg-ohm range), it might indicate a problem. In my case, one of the capacitors was simply shorted after removal. There's tons of other things that could have failed in the EML. look for discoloration or any evidence of excessive heat. Might have a bad transistor or two. If it had a specific problem, like an input or output not working as expected, one could reverse engineer the pinout, trace back to the components, but ultimately that's a shit-job without a schematic and a test mode. If it's simply Dead, your option is to run down the input power sections, but any kind of board-level troubleshooting approaches diminished returns quickly.
https://www.bimmerforums.com/forum/s...+module+repair

[RobertRO]

[...] for M70 owners, time has come that DME's and EML are at the end of their lifetime.

That actually is a major concern for the future of M70 powered E32 750i and E31 850i cars.
Indeed, one useful approach is to collect information and ideas about how to repair and extend the service life of the original DMEs and EMLs. However, these electronic units are about 3 decades old (give or take a few years), and it is expectable that they will become increasingly troublesome, as more years pass by.

Therefore, as an alternative, I think that the community should also consider a joint effort to develop a plug-and-play aftermarket ECU (e.g. based on Megasquirt, or similar), along with a proper tune. And I believe that modern replacements for the DKs (and possibly MAFs, depending on the algorithm implemented in the ECU) should also be included in the project.

Not long time ago I spent some time playing with a custom-built Megasquirt ECU, but for the M30 engine.
It was never meant to go beyond experimental/hobby phase, but it clearly showed that, investing the right amount of time and effort, it has the potential to lead to a suitable and reliable replacement for the original Motronic. It doesn't mean that it may be just as good, but for sure it can go beyond the "good-enough" threshold.

[paulmer]

Very interesting response RobertRO. Definitely agreed, sitting here at full attention.

Would also be great if someone in the community could manufacture new, high-grade wiring harnesses... I know a lot of issues with M70 reliability are due to wiring harness failures due to aging of plastic, etc.

Maybe we could have a GoFundMe for this? I'm sure many from the E31 community would pitch in, too.

[zapass]

There are some Plug&Play ECUs for M30:
https://k-data.org/en/kdfi/pnp-bmw/2....4-pnp-bmw-m30
https://www.condorspeedshop.com/prod...quirtpnp-gen-2

Do not know about M70, did not search for it

[RobertRO]

There are some Plug&Play ECUs for M30

No, those are not Plug&Play ECUs!
Allow me to explain this.

Regarding the first link in your post above:
In 2015 I have purchased a Kdfi v1.4 PNP M30 ECU, manufactured by K-Data in Germany. At that time, I was happy that I found an European supplier of an aftermarket ECU for M30. But it soon proved to be a very bad decision.
First, I did not search enough before buying. If I had searched, I would have found out that Kdfi is nothing but an illegal rip-off of Megasquirt. Further, the unit I bought arrived with a hardware failure. I've sent it back to be fixed. I've got it back, but it never worked properly. It randomly kept on losing the VR signal from the cranckshaft sensor. (note: the exactly same VR sensor works fine with both Motronic and Megasquirt). Customer support from K-Data on this issue: zero.
So I simply scrapped it, assuming a lost of 500+ Euro and a lot of time. I paid for my ignorance.

Regarding the second link in your post above:
That seems be a legit Megasquirt unit. However, it is not Plug&Play, not even close. At most, you can say it is a direct "Plug" into the Motronic 1.3 connector, and that's the end of it. Just to name the major things to do: you still have to deal with the MAP, the lambda probe and its controller, the TPS.
And, most important, it is delivered with a tune that's simply not good for the M30 engine. You will have to tune from scratch, which is a major endeavor by itsself.
Obviously, not Plug&Play at all.

As far as BMW M70 engine is concerned, I am not aware of any aftermarket ECU that could at least be considered "Plug".
That's why I suggested, in my post above, that the community should consider a joint effort to develop a Plug&Play ​solution. And I believe that this is quite unlikely to ever happen. I will be glad to be proven wrong.

[zapass]

Thanks for clarification, I was not aware of that.