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Old 12-08-2019, 12:01 PM
X5Cat X5Cat is offline
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Quote:
Originally Posted by ard View Post
Can you perform a VANOS function test? When vanos soleniods become fouled w old oil, sludge, they can become sluggish and lead to odd performance issues. Not bad enough to throw a code, but they will either fail or show borderline VANOS test results. Should be a program in ISTA or other BMW-specific code reader/computer to do this. A sluggish vanos on one side can mean that side is not seeing the right AFR for part of the RPM range- you get hosed AFRs but it is never so bad, all the time, to trip a full AFR error code
Not sure. I will have to read up on VANOS (variable nockenwellen steuerung -- see what I've learned already?). Not sure if OBD Fusion gives a reading for that.

My O2 sensor socket did not fit yesterday so I bought one last night. Hope to dig back into it sometime today. Concerned about how far around the back of the engine I am going to have to chase to find the other end of the O2 wiring harness for Bank 1 Sensor 1, and about how tough it's going to be to reach Bank 2 Sensor 1. Probably less than 50/50 chance these new upstream sensors will fix the problem, but as you say, they need to be changed out anyway.
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