MAP-sensor in passenger compartment? DTA S80pro

[Antral]

Twisting wires makes them easier to thread down heatshrink IMHO and looks more pro.

[Anders_Karlsson]

I hope GM choose a good wire for the magnetic crank sensor, it looks ok to me.
It is shielded and i guess the two wires inside are twisted in some way.
If this cable will not work i will replace it with something else.

One thing that i noticed is that the signal wire from the crank sensor is pin 2 on the stock wiring diagrams.
DTA S80 wiring diagram states that pin 1 on the sensor is signal. The sensor is a standard Bosch unit used on many Opel/Vauxalls from early 90s.
I guess the crank oscilloscope will tell if i have it wired the wrong way.

[Antral]

That is because DTA have chosen to use pin 1 for the signal follow the wiring diag at all times for the best results.

[Anders_Karlsson]

Ok, maybe the Motronic ECU inverts the signal in some way. I will go with the DTA wiring then.

Work will continue tomorrow, need to install some flyback diodes for the idle valve and variable length intake.

[stevieturbo]

Switching polarity of a magnetic sensor changes the waveform. It basically reverses it so the falling edge the ecu wants to see will occur at a different time, so the signal may not be understood.

It's a small change, that can have huge consequences.

This is a scope of a Subaru cam sensor, 3,1,2,1 pattern. This is the sensor wired correctly for most ecu's. The red circle is what most ecu's will look for as a trigger having been recognised, where the voltage falls through the zero line. ie falling edge.



This is the exact same engine, same sensor etc etc but with the wiring reversed ( polarity swapped on scope, not ecu otherwise it wouldnt run )

You can see the waveform is reversed and the falling edge now occurs at different times. However if the ecu was configured to see a rising edge then it would be fine. ie where the line passes through the zero line on its way upwards
As we cannot change this setting on the DTA it must be correct, and I'm assuming it works off a falling edge. ( never actually checked mine lol )

[Anders_Karlsson]

I have wired the sensor according to the wiring diagram now, will probably work fine.