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ST170 VVT Cam Trigger Issues

EFI Tuning Fundamentals

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I am tuning an ST170 Duratec engine, converted to a coil-on-plug setup with a maxxecu mini already installed. As the mini can only operate one analog trigger sensor, the cam sensor has been swapped with a hall effect cherry sensor bought from a local maxxecu dealer. The sensor runs on 5v and pull-up resistor is enabled within software.

The car runs great on sequential ignition and the trigger data from the internal oscilloscope within the mtune software seems like there are no issues whatsoever but i cannot get the intake cam to display any angle value from vvt settings no matter how many offset values tried as it is constantly "invalid" and randomly flashing an arbitrary angle (ie: -23 degrees - invalid for about 15 seconds and 87 degrees). Also, the trigger logger data are all random ups and downs, not even following a pattern let alone what the ST170 cam trigger pattern should be.

The rated airgap of the cherry sensor is given as 1-1.5mm and i've tried every gap in that range incrementing by 0.1mm. Also double checked the connections of vvt solenoid and sensor but couldn't find any issues. I am now at a point where i cannot think of any other reason why it shouldn't work. The VVT with the previous ecumaster setup was supposedly working so it shouldn't be anything mechanical i guess. Any suggestion or guesses are welcome at this point

I've attached the oscilloscope and trigger logger screenshots.

Attached Files

The log data shows random ups/downs because the logger is nowhere near fast enough to capture it properly. Logging that data is only useful to see if a sensor is dead by seeing if it's "stuck up" or "stuck down". That's not a ST170 or maxxecu issue. That's just the nature of trigger values.

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