So I decided to experiment and scoped a MAP sensor during a crank event to see if I could use it in place of a pressure pulse sensor. In short, it works well enough to see valve events.
Just thought I’d share with you guys.
Would this forum benefit from an “unconventional testing” sub forum?
Making Pressure Differential Sensors (PDA Sensors) for pressure pulse diagnostics.
Currently servicing Central Texas.
Started on a 5V setting, went to a 2V setting and still needed some zoom. No screenshots unfortunately but I plan on experimenting with it again at some point and I’ll save some captures. I was very surprised to see a perfectly usable waveform that showed valve events. Actually discussed this with others and some suggested to completely disconnect the sensor electrically and use an external 5v supply.
Making Pressure Differential Sensors (PDA Sensors) for pressure pulse diagnostics.
Currently servicing Central Texas.
Andy.MacFadyen wrote: Bosch hotwire MAF will also intake pulses but how useful it could be is doubtful.
Still very interesting at least to me. However, the location of the sensor is an important factor. Before the throttle plate, then you’re not gonna get the entire picture. In comparison as to where if the sensor is after the throttle plate.
And... could those intake pulses from a MAF sensor be interpreted to determine if the throttle plate is closing properly or if it might be stuck open by debris or other obstructions? While maybe not practical, I’d be curious about what the differences in a waveform will produce.
Making Pressure Differential Sensors (PDA Sensors) for pressure pulse diagnostics.
Currently servicing Central Texas.
Andy.MacFadyen wrote: Bosch hotwire MAF will also intake pulses but how useful it could be is doubtful.
Still very interesting at least to me. However, the location of the sensor is an important factor. Before the throttle plate, then you’re not gonna get the entire picture. In comparison as to where if the sensor is after the throttle plate.
And... could those intake pulses from a MAF sensor be interpreted to determine if the throttle plate is closing properly or if it might be stuck open by debris or other obstructions? While maybe not practical, I’d be curious about what the differences in a waveform will produce.
The MAF I first noticed it on was on a turbo diesel so no throttle plate I could actually see the pulses at idle although the MAF was before the turbo with a whole load of junk, turbo, inter cooler, EGR between the MAF and the cylinders. At least on a diesel it could be a method for spotting a valve related issue,
" We're trying to plug a hole in the universe, what are you doing ?. "
(Walter Bishop Fringe TV show)
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