Non start!
05-03-2024, 04:20 AM
#17
Just to round up, this is the Tech’s theory on what is happening:
“Excellent news - I love it when obscure causes recur; the one's where you end up saying: what are the chances!?
The failure must produce a similar electrical impulse in the wiring - self-energising the sensor, which in turn sends a signal back; enough to start the cycle but incorrect for the DME to do its' real job. Definitely a job that could (did?) waste hours of diagnosis time - the operational tests in the DME test plan don't allow for the specific failure mode in this case.
Glad to have helped!!”
“Excellent news - I love it when obscure causes recur; the one's where you end up saying: what are the chances!?
The failure must produce a similar electrical impulse in the wiring - self-energising the sensor, which in turn sends a signal back; enough to start the cycle but incorrect for the DME to do its' real job. Definitely a job that could (did?) waste hours of diagnosis time - the operational tests in the DME test plan don't allow for the specific failure mode in this case.
Glad to have helped!!”
05-03-2024, 01:10 PM
#18
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Just an update on this, I was directed to the crank sensor by a couple of people who have experienced these symptoms, and despite an oscilloscope showing a good signal, bizarrely this continued after the engine stopped cranking! That is exactly what it was, 5 hour train journey to collect tomorrow, it’s like new car day all over again 
__________________
Loren
Systems Consulting - Automotive Electronics
Specializing in Porsche cars
http://www.systemsc.com/
Loren
Systems Consulting - Automotive Electronics
Specializing in Porsche cars
http://www.systemsc.com/
05-03-2024, 01:29 PM
#19
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Just to round up, this is the Tech’s theory on what is happening:
“Excellent news - I love it when obscure causes recur; the one's where you end up saying: what are the chances!?
The failure must produce a similar electrical impulse in the wiring - self-energising the sensor, which in turn sends a signal back; enough to start the cycle but incorrect for the DME to do its' real job. Definitely a job that could (did?) waste hours of diagnosis time - the operational tests in the DME test plan don't allow for the specific failure mode in this case.
Glad to have helped!!”
“Excellent news - I love it when obscure causes recur; the one's where you end up saying: what are the chances!?
The failure must produce a similar electrical impulse in the wiring - self-energising the sensor, which in turn sends a signal back; enough to start the cycle but incorrect for the DME to do its' real job. Definitely a job that could (did?) waste hours of diagnosis time - the operational tests in the DME test plan don't allow for the specific failure mode in this case.
Glad to have helped!!”
05-03-2024, 07:38 PM
#20
The tech is very experienced and was seeing a square wave form.
I’m not hugely experienced with electronics but have seen some very strange signals from sensors effected by interference in industrial boiler rooms, so probably not a new phenomenon!
I posted the outcome to potentially help others experiencing similar symptoms, not to feed the trolls!
See ya
I’m not hugely experienced with electronics but have seen some very strange signals from sensors effected by interference in industrial boiler rooms, so probably not a new phenomenon!
I posted the outcome to potentially help others experiencing similar symptoms, not to feed the trolls!
See ya
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Dinosaur33 (05-04-2024)