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Premium Member
2000 E46 323i, 3.0L, 2.8L and 2.0L Z3's
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2,114 Posts
Man, your post has got me excited. Thank you for posting the photo of the Measurement Block 1 data. It's just the information I've been looking for. More on that later.

Yes, your engine is running cold. Do you have an automatic transmission? If so, the thermostat that is faulty could be the Automatic transmission thermostat in the bottom of the expansion tank. If the main engine thermostat has been replaced and it has not fixed the problem, then the automatic thermostat would be your next point of call.

Back to that Measuring Block 1 photo.
I've been working on a number of "Unexplained Rich Running" cases on E46's with the MS45 DME. I think the barometric sensor on the DME PC board is faulty (reading low) and causing the problem.

Your photo of Measurement Block 1 shows:
  • That INPA reports the Baro sensor value "umgebungsdruck" in the MS45 DME. I haven't been able to test this.
  • That your Baro value is likely low at 862.2 hPa. That's a really super low winter value and you're in summer and taking about driving in hot weather. Your Baro should be above 1010 hPa.
Could you please do a bit of testing for me?
Please provide:
  • The ambient air pressure in your area (weather forecast, airport data, Met Service etc) and the Baro pressure in your DME on that same day.
  • With a hot engine at idle, the 4 fuel trims (integrator and Multipilcative for each bank).
 

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Premium Member
2000 E46 323i, 3.0L, 2.8L and 2.0L Z3's
Joined
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2,114 Posts
Thank you for the data.

Well that is very interesting. Total fuel trims running in -2.5% to -2.8% rich at hot idle, engine up to temp and a Baro difference of 187.7 kPa = 1,6500m (4,800 ft) in higher altitude.

If you are running E10 fuel, your normal total fuel trim operating range is 0.5% to 8.5%. The engine is running rich at idle, but not running too rich, but is following the trends I'm, expecting.

Here is my thread on the topic: Barometric Pressure?
 

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Premium Member
2000 E46 323i, 3.0L, 2.8L and 2.0L Z3's
Joined
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2,114 Posts
If the rich fuel trims at idle are not giving you any problems, then don't worry about it. The other E46 DME MS45's I'm working with have -10% to -15% rich total fuel trims and are getting misfires and performance problems. Just be aware of it.

What would be interesting, is to get a set of the 3 standard OBD Fusion logs and a Rev-Rise log to see how they compare to the logs of the other E46's. You may already have a OBD2 dongle/adapter. The cost of OBD Fusion is cheap.

If you are really super keen to do TestO, then I can give you a list of PID's to log. You could increase the Baro pressure to see if it improves the total fuel trims. Or, you could reduce the Baro pressure to see what happens. I agree, don't worry about the rate of change part.
 

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Premium Member
2000 E46 323i, 3.0L, 2.8L and 2.0L Z3's
Joined
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2,114 Posts
Had a thought in the middle of the night. The MS45 DMe has 4? measurement blocks. Could you please post a screenshot of all the measurement blocks with the engine at hot idle. This will give me a record of the data that is available plus I'm interested in your MAF values, both in kg/hour and volts.
 
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