There are some subtleties between these two posts:
Quote:
Originally Posted by Zulfiqar
You are correct on the vvt part of it.
The cam sensor reports to the ECU the actual cam position, the ECU then has confirmation that the cam has advanced.
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Yes, this is so the ECM knows to trigger a no cam advance trouble code.
Quote:
Originally Posted by GeoffinOz
Well, that's not my understanding with this engine, the tech articles are quite specific that the ECU controls the input valve timing (over a limited range) using the difference between TDC (from the crank sensor) and the camshaft position in real time from the Camshaft sensor.
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For this to be true, the cam magnet would need to see a PWM input to modulate the oil valve. I'm not so sure this is the case since oil pressure isn't well regulated and the PWM dwell would constantly be trying to catch up making for a surge.
I don't think there is any benefit to a partly advanced cam over on / off anyway and I don't recall seeing a " cam advance X degrees "data value when wing a Star on my 97 SL or C280 ( this has ME 2.0 / 2.1 )
Hang a scope on the cam magnet input and have a look. ( or for a more portable way, a volt meter )