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Discussion Starter #1
So, I'm messing around a bit with some datalogging software and noticed that for several (3 of 4) of my VANOS readings, the actual value is a bit off from the expected value.

3169 RPM, 20% Throttle, 3rd gear, 37 MPH

Bank 1
Intake Expected: 150
Intake Actual: 147.3
Exhaust Expected: 131.5
Exhaust Actual: 130.3

Bank 2
Intake Expected: 150
Intake Actual: 146.6
Exhaust Expected: 131.5
Exhaust Actual: 127.6

Does anyone have any idea what an expected delta should be between expected and actual?
 

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That is very interesting, is the expected value coming from the ecu, as a function of what it would expect at that point? If so, then potentially the VANOS is seeing something sometimes that makes it shift the cams in a different amount than normal. Perhaps the expected value is a "best-case" or "ideal" scenario? Very interesting.
 

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Discussion Starter #3 (Edited)
Yes, the DME actually controls (orders) the VANOS units, so I believe "expected" actually means "ordered."

The only reason I can think that the VANOS can't achieve what was ordered is if a solenoid is not operating properly (ISTA tells me I have 3 drawing high current) or if a VANOS adjustment unit is not moving freely forward and aft.

Hopefully, someone more knowledgeable about vanos (like gjs) will chime in and offer their thoughts.
 

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Yes, the DME actually controls (orders) the VANOS units, so I believe "expected" actually means "ordered."

The only reason I can think that the VANOS can't achieve what was ordered is if a solenoid is not operating properly (ISTA tells me I have 3 drawing high current) or if a VANOS adjustment unit is not moving freely forward and aft.

Hopefully, someone more knowledgeable about vanos (like gjs) will chime in and offer their thoughts.
Im sure that you have expected , then you have some tolerance for deviation from what is expected.
When that tolerance is over , then you have CEL.
Your actual is quite close to expected.

If you have around you some BMW equipment you can always make the VANOS test procedure.
 

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Discussion Starter #5 (Edited)
I'm reading out the VANOS information using BMW's ISTA/D application. I have performed the VANOS ventilation procedure and then the VANOS test. Attached below are the results of the test. It would be nice if I knew what a perfectly running car looked like :3:

Screen Shot 2013-01-17 at 5.15.02 PM.png

Screen Shot 2013-01-17 at 5.15.08 PM.png

Screen Shot 2013-01-17 at 5.15.17 PM.png

Screen Shot 2013-01-17 at 5.15.20 PM.png

Screen Shot 2013-01-17 at 5.15.25 PM.png

Screen Shot 2013-01-17 at 5.15.32 PM.png

Screen Shot 2013-01-17 at 5.15.52 PM.png

Screen Shot 2013-01-17 at 5.15.55 PM.png

Screen Shot 2013-01-17 at 5.15.57 PM.png

Screen Shot 2013-01-17 at 5.15.59 PM.png
 
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