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BMW M44 cam trigger

Paul Milligan

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I'm trying to sync up a BMW 4cyl M44 engine. The cam trigger on the intake cam as an odd profile. I've attached some pics that I grabbed off of another forum to explain the profile. How can I make this work? It is running a 60-2 VR crank sensor. The cam sensor is hall. The cam sensor is at the red dot in one photo when the engine is at TDC.



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Couple of options.

The preferred one would be to remove 3 of the 4 teeth on the cam leaving a single tooth.

This will allow sequential fuel and ignition.

Option 2 would be to run in group fuel and wasted spark (assuming 4 coils) and trigger off the crank only.

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I made some headway. I modified the cam trigger wheel to have one tooth. It triggers when cyl #1 is at TDC. I also switched to a hall effect crank sensor as I was having trouble with the voltage thresholds on the VR sensor. I'm still getting one trigger error per crank revolution. The RPM signal is reading about 1000rpm when it is only cranking at 150 - 200rpm. This is when I have it set to sequential mode. If I switch to batch injection, the rpm reads correctly but I still get one error per crank revolution. I currently have the trigger priority set to #1. Should it be set to trigger #2? Am I running into trouble since my cam triggers at the same time as crank triggers at TDC?

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Hmm RPM in theory should not change based on the injection mode.

I assume you do have trig 1 set to crank, tooth count 60, missing teeth 2 and trig 2 as 1xCam

Both will be opto/hall

Trig 1 is the normal priority setting but certainly no harm in trying trig 2.

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