DME Repair Needed

cwhite · 28th February 2006, 23:35

Hi, Got a 2nd (dead) DME for my e28 M5 and want to investigate getting it working. I am going to spend some time looking for obvious solder cracks etc.

Any ideas on a place that can repair the unit. Found one place on-line but they wanted $500 which a little spendy for the piece of mind that comes with having spare parts.

Has anyone ever tried a 055 DME in a USA car instead of the 079? Since I put on the EURO headers I thought the EURO DME would be a nice next step

Thanks

CW

Izzyzx · 1st March 2006, 02:35

Cwhite,
I'm not a mechanic or a computer geek, but it would seem to me that
Bosch didn't not design a computer for every model car in their product line.
It would also seem more reasonable that many DME are interchangeable with the exception of the EPOM (The Chip)... which is programmed to control the fuel injector and ignition timing to a specific engine design... If you know a computer geek or electrical engineer he/she might be able to confirm this... In fact someone has a 0261200027 (528e) on ebay for $5.

M5 DME Part Number
OEM Number: 0261200079
Manufacturer: Bosch

This BMW part works for the following BMW models and year ranges:
1984 1985 1986 1987 1988 1989 BMW M5 4DR ( E28 ) BMW M6 2DR ( E24 )
BMW M635CSI 2DR ( E24 ) EURO w/cat

Izzyzx

MarkD · 12th March 2006, 20:03

Quote:

Originally Posted by cwhite

Hi, Got a 2nd (dead) DME for my e28 M5 and want to investigate getting it working. I am going to spend some time looking for obvious solder cracks etc.

Any ideas on a place that can repair the unit. Found one place on-line but they wanted $500 which a little spendy for the piece of mind that comes with having spare parts.

Has anyone ever tried a 055 DME in a USA car instead of the 079? Since I put on the EURO headers I thought the EURO DME would be a nice next step

Thanks

CW

What is wrong with your DME? Is it a no spark problem? If so, I I can fix it for $250 USD (I am in Canada) or I can probably have it fixed at my chip shipping center in Ohio. (I will instruct them how to repair it)

Mark D'Sylva

MarkD · 12th March 2006, 20:11

Quote:

Originally Posted by Izzyzx

Cwhite,
I'm not a mechanic or a computer geek, but it would seem to me that
Bosch didn't not design a computer for every model car in their product line.
It would also seem more reasonable that many DME are interchangeable with the exception of the EPOM (The Chip)... which is programmed to control the fuel injector and ignition timing to a specific engine design... If you know a computer geek or electrical engineer he/she might be able to confirm this... In fact someone has a 0261200027 (528e) on ebay for $5.

M5 DME Part Number
OEM Number: 0261200079
Manufacturer: Bosch

This BMW part works for the following BMW models and year ranges:
1984 1985 1986 1987 1988 1989 BMW M5 4DR ( E28 ) BMW M6 2DR ( E24 )
BMW M635CSI 2DR ( E24 ) EURO w/cat

Izzyzx

They are not as interchangeable as you may think. That 0 261 200 079 DME is for the early S38, not the M88 or any other motor. The 0 261 200 027 from the eta motor WILL NOT work in an S38 or M88 even if you changed the EPROM. It's a different generation of DME with an RCA 1802 cpu. The 079 has an Intel 8051 compatible cpu.

Mark

Izzyzx · 13th March 2006, 03:49

Mark,
Very good information. You seem like a expert in these matters... As you might have guessed I was not aware of any differences (CPU, MB, connectors, and/or mounting...). The fact that I used the ETA DME as an example, was only to stimulate thinking and conversation. With that said:

Is the Intel 8051 CPU and main board (MB) configuration unquie to BMW M5 E28? And do any other auto manufacturer us this Bosch DME CPU and MB?

MarkD · 13th March 2006, 04:05

Quote:

Originally Posted by Izzyzx

Mark,
Very good information. You seem like a expert in these matters... As you might have guessed I was not aware of a CPU difference. Is the Intel 8051 CPU only used on the E28 M5? Is this CPU and main board configuration unquie to BMW M5? Does any other manufacture us this CPU and MB?

A cpu from the 8051 family was used on all BMW's sold in NA from 1985 till the M50 motor was introduced, when they switched to an Intel 8096.

Some of the DME's using the 8051 are compatible, but you can not switch EPROMS between them as they are not hardware compatible. For example, the 153 DME was in an E30 and you can upgrade to the newer 173, but the hardware is quite different.

But in the case of the 079 DME from the S38, it is very similar to the 071 from the S14, and also the 059 from the M30. Yes you can even take the EPROM from one of those and swap into the other, but I wouldn't do it as even though the car will start and run, each has slightly different hardware and some functions won't be available. (you could do it temporarily if in a pinch). Those DME's are also very similar to the ones from the Porsche 944 DME.

I hope that answers your question.

Mark

Izzyzx · 13th March 2006, 21:30

Mark,
I guess what I’m trying to understand in my limited knowledge of car electronics. Why Bosch wouldn’t manufacture a baseline DME and made a firmware changes for the different geographies and engine characteristics, especially for the same auto manufacturers.

Last questions: What do you mean by hardware differences? Are you talking about components and function or mounting/connector?

If I had a 1988/89 535i/735i DME it would not work if I used the M5 EPORM?

Finally ... Which after market performance chip manufacture has the best design to increase low end torque?

I owe you a beer... Thanks