Replacing DME in EWS 525I

[Joestancampiano]

This may be of interest to those of you who do this work for a living. After having an intermittent tach problem for the last 6 months, and making myself nuts tracking the cause, I found that the problem was in the DME. Late model 95s have the EWSII security system which needs a coded key to match the EWSII box, which checks matching code in DME before car will start. The solution to replacing the DME was to go to the dealer and pay about $1000 for a new DME which was then coded to the cars EWS circuit. I was told a used DME could not be coded and wouldn't work.
After doing lots of thinking, I bought a used DME ($200) took the eprom form the original DME and put it in the used one. After everyone told me this wouldn't work my car evidently ignored them all and started up just fine....Tach problem is GONE !!!!!!! I think this will also work if you put in an aftermarket chip (Conforti) as the chip somehow defeats the EWS coding of the DME. (if your ....413 DME has a silver label, you have EWSII). I don't think this will work on 530/540 only on 325/525 in 1995
Hope this helps someone avoid all the reasearch I had to do on this problem

Joe

[MarkD]

This may be of interest to those of you who do this work for a living. After having an intermittent tach problem for the last 6 months, and making myself nuts tracking the cause, I found that the problem was in the DME. Late model 95s have the EWSII security system which needs a coded key to match the EWSII box, which checks matching code in DME before car will start. The solution to replacing the DME was to go to the dealer and pay about $1000 for a new DME which was then coded to the cars EWS circuit. I was told a used DME could not be coded and wouldn't work.
After doing lots of thinking, I bought a used DME ($200) took the eprom form the original DME and put it in the used one. After everyone told me this wouldn't work my car evidently ignored them all and started up just fine....Tach problem is GONE !!!!!!! I think this will also work if you put in an aftermarket chip (Conforti) as the chip somehow defeats the EWS coding of the DME. (if your ....413 DME has a silver label, you have EWSII). I don't think this will work on 530/540 only on 325/525 in 1995
Hope this helps someone avoid all the reasearch I had to do on this problem

Joe

Hi Joe,
was your new (used) DME an EWS-II DME? I am quite sure that if you take your EWS EPROM and install in another DME or either type, it will work.

What does not work (at least for me) is:

1) installing NON-EWS chip in an EWS DME
2) installing complete non-EWS DME and chip into EWS car

Some people have said that you can defeat the EWS with the cases above but it didn't work for me.

I am making an EWS chip for the m50tu with EWS, but have encountered a technical problem and the lack of a test car isn't helping. Next week someone is coming over with a test car.
(the problem has to do with calculating a checksum on the CODE I modified to make a generic EWS chip, as there are multiple checksums in that chip)

The same problem exists in the M60 EWS chip also. Right now I need the stock chip to make an EWS chip for these cars.

I did have success making a generic EWS-II chip for the 3.8l E34 M5 and it runs really well.

Mark

[Joestancampiano]

Used DME was from an EWS car so I put an EWS epron into an EWS DME. Didn't try useing a non EWS DME with an EWS eprom mainly because the EWS DME was much cheaper than the non EWS and I thought that this way had the best chance of working. I had a Conforti chip in my old DME but I haven't tried installing it in the used one at this time. I'm so happy it's fixed I don't want to risk problems if the preformance chip caused the original problem (do miss the power though)

[MarkD]

Used DME was from an EWS car so I put an EWS epron into an EWS DME. Didn't try useing a non EWS DME with an EWS eprom mainly because the EWS DME was much cheaper than the non EWS and I thought that this way had the best chance of working. I had a Conforti chip in my old DME but I haven't tried installing it in the used one at this time. I'm so happy it's fixed I don't want to risk problems if the preformance chip caused the original problem (do miss the power though)

What you did is guaranteed to work as the EWS code is in the EPROM. You should be able to install the performance chip now also.

Mark

[Joestancampiano]

Thanks Mark, let me know when you get your chip sorted out

Joe