Modifying a BMW E34 M5 dash (NMC9346EN chip)

European GM ECUs and PCMs
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Re: Modifying a BMW E34 M5 dash (NMC9346EN chip)

Postby juliohernandez85 » Tue Mar 30, 2021 2:09 pm

Thanks, Antus. I managed to attach the pictures in the original post.

I am by no means an expert in programming. I do get the basics and I will get the car to a guy who specializes in car eeproms. The problem is that BMW arrived in Mexico in 1994, and since the E39 was being released in 96 they did not bring the E34, just the E36, E38 and E31. The few E34 that were brought to the country were special deliveries for a handle of wealthy businessmen.

This particular car was purchased by the owner of one of the largest banks in Mexico. He got it armored and paid over 237k USD for it :o

That means that the knowledge of BMW EEPROMS is almost non existent... :thumbdown:

Let´s hope someone here has information.

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Re: Modifying a BMW E34 M5 dash (NMC9346EN chip)

Postby mikrovega » Thu Apr 08, 2021 11:40 pm

Hi,

Is the F.G. number indicated correctly and according to your car's VIN last 7 digits?

Unfortunately this is no so easy as it might be to exachange the part of coding as if you will do so, you will make the speedo to show a "dot" by the mileage at least or reject the plug.
The best proposal is to use other's car coding but in such a case F.G Number (VIN) will reflect other car (donor).

Which speedo type do You have? The one with blue rear plastic cover (with the bigger EEPROM)?

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Re: Modifying a BMW E34 M5 dash (NMC9346EN chip)

Postby juliohernandez85 » Fri Apr 09, 2021 2:10 pm

Hi, microvega

The VIN number showed in the Cluster test is 0000000 (same as the sticker on the coding plug). I have found other cases on the web for late models (1995)

The cluster has a blue back.

I don´t mind if I cannot input the VIN in the chip, but the most important thing is to change miles to km (changing D3 to D2 in the second row) and code the tachometer for an 8 cylinder engine, since the rpm goes way up.

Thanks for your response.

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Re: Modifying a BMW E34 M5 dash (NMC9346EN chip)

Postby mikrovega » Fri Apr 09, 2021 4:13 pm

Could be that the coding plug was replaced but it does not matter...

I would need to look for V8 E32/E34 speedo as I should have it somewhere. AFAIK it has blue back / blue coding plug and ECE (km). Typically all V8 have had automatic transmission as well.

Have you tried to modify the content on your own?

Kai and Gasplanet, mentioned in the previous messages seems to have some experience.

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Re: Modifying a BMW E34 M5 dash (NMC9346EN chip)

Postby j_ds_au » Fri Apr 09, 2021 11:07 pm

antus wrote:The next part of the problem was that we wanted to move the configuration from the brown to the blue IC as that was the one we could write. Being twice the size I stacked 2 copies of the data from the brown code plug. Verification succeeds but the car rejects the code plug, and dash the dash is not correctly configured. The gauges are all wrong for example idle rpm reads at 200 rpm. Does anyone know why stacking a working brown code plug and dropping it on a blue does not work? We dont have a sample bin of the larger IC, the chip we had was a BMW spare that contained all FF and had never been programmed.

In parallel ROM devices, stacking is simply a means of placing the desired data (from a smaller part) at the top of a larger part. The fact that it is the upper part of the larger device that is used, is a quirk of the way that pins are re-allocated to accommodate more address lines for larger parts.

None of that applies for a serial ROM device (since the additional address bits are sent serially over a single data pin). So in this case, the desired data is normally located at the bottom of the device, and the top of the device is unused (and might even be expected to be filled with 00 or FF).

However, the serial protocol for a larger part might have more bits than the smaller part, so the firmware that is trying to communicate with the larger-than-expected part, may not clock out sufficient bits to correctly address it (complete the serial transaction).

Joe.

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Re: Modifying a BMW E34 M5 dash (NMC9346EN chip)

Postby juliohernandez85 » Tue Apr 13, 2021 12:28 am

mikrovega wrote:
I would need to look for V8 E32/E34 speedo as I should have it somewhere. AFAIK it has blue back / blue coding plug and ECE (km). Typically all V8 have had automatic transmission as well.


It would be very helpful if you could share the V8 model BIN file, that way it would reduce to hit and miss modifying the Hex code.

Cheers.

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