Cocktail of 3.0i Trouble Codes - Where to Begin?

[richardb]

4.16 g/s at idle (new MAF) vs. 5 g/s at idle (old MAF) with the same conditions, engine warmed up and daytime running lights on.

If my math is correct that represents a 16.8% change. Not insignificant, but perhaps other factors such as temperature and barometric pressure can explain that?

Does anyone know if Bentley or BMW offers operating specs or range for a MAF?

[upallnight]

Originally Posted by richardb

4.16 g/s at idle (new MAF) vs. 5 g/s at idle (old MAF) with the same conditions, engine warmed up and daytime running lights on.

If my math is correct that represents a 16.8% change. Not insignificant, but perhaps other factors such as temperature and barometric pressure can explain that?

Does anyone know if Bentley or BMW offers operating specs or range for a MAF?

Your math is incorrect. To go from 4.16 g/s to 5 g/s is a difference of 20.19%

[crystalworks]

I also get 16.8%?

5 - 4.16 = 0.84, 0.84 ÷ 5 = 0.168 × 100 = 16.8%

[richardb]

Been a while since I had to do this math, but I think using the initial value 0.84 / 4.16 gives you a 20.19% increase from 4.16 to 5.

Regardless, how that is interpreted is more important. Bentley manual offers nothing with respect to proper MAF flow readings or operating parameters.

Does anyone have something from BMW or VDO/Siemens to reference?

[upallnight]

Originally Posted by crystalworks

I also get 16.8%?

5 - 4.16 = 0.84, 0.84 ÷ 5 = 0.168 × 100 = 16.8%

That would be correct if you are talking about going from 5 g/s to 4.16 g/s, but if the correct reading is going from 4.16 g/s to 5 g/s you will divide by 4.16 not 5.

We know that 4.16 g/s is closer to what the Value should be so we are looking at going from good to bad.

[upallnight]

Here's a video showing what the MAF should be at idle as well as the 02 sensors. As you can see the MAF is below 5.0 g/s. This is a known good reading.

https://www.youtube.com/watch?v=zyh_4SktmFM

[crystalworks]

Originally Posted by upallnight

That would be correct if you are talking about going from 5 g/s to 4.16 g/s, but if the correct reading is going from 4.16 g/s to 5 g/s you will divide by 4.16 not 5.

We know that 4.16 g/s is closer to what the Value should be so we are looking at going from good to bad.

Gotcha.

[80stech]

You are chasing your tail with the MAF readings. There is no way to pin down a known good reading within a range that small because there are too many variables which is also why you won't find it in the service manual.

[upallnight]

My "Known Good" is when I had my X and decided to make a video of what these parameters should be based on no Check Engine light and No pending code or active code in the DME.

[80stech]

Even differences in volumetric efficiency due to camshaft timing will throw a wrench into that.