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      09-19-2019, 05:26 AM   #8
doughboy
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Drives: 2018 M2 Comp 6MT
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Quote:
Originally Posted by _RS4_ View Post
When you disable the pressure sensors, the ECU won't command the regenerations anymore. Am I right?
These don't actively "regenerate" like a diesel PF by adding fuel to burn the soot off.

They are entirely passive and the soot burns off during overun (deceleration) when exhaust stream oxygen levels are high and temps are high. The DME will try to do this when conditions are right, ie. high exhaust temps and longer periods of deceleration - motorway useage mainly. It has to leave the throttle plate open and allow the engine to "pump" air through the system with no fuel added or ignition so the natural air oxygen (20%) will burn the soot off if it is hot enough.

If soot builds up too much then the back pressure builds up so the DME will look to allow more airflow during overrun and reduce power output if necessary (!)

As the ash (from burnt soot) builds up and this cannot be removes, the DME will gradually reduce engine power output until ultimately the OPF needs replacing (100-150K miles)

This isn't something BMW put in the sales brochure!!


BTW excellent post MR

Last edited by doughboy; 09-19-2019 at 05:42 AM..
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