Found the correct wiring loom manual -
http://www.volvowiringdiagrams.com/v...20Diagrams.pdf
Page 219 shows the back of the combination instrument panel (CIP).
With the help of my best mate Vitch (who owns a T5 2.4 V70 phase 2) - we used his oscilloscope to analyse the signal wave forms looking for something that might give us a useful tacho signal for engine speed. We searched the whole of plug A.
Pin 13 - Generator Signal D+ looked promising but it was a bit noisy. Nothing else inside the dash gave us any joy.
We got a better signal from the control wire supplying the coil packs. We discovered good clean signal but probably the wrong sort as the Blitz didn't seem happy to calibrate with it. It's the same wire that Hamish uses on the Dynojet, with an induction loop detector. Shame it didn't quite work.
Vitch reckons that with a small circuit we could convert that analogue voltage signal into a more digital form that the SBC can use. I have to talk to Blitz to see what kind it needs.
Main issue is that my car year is the very early ME7. It was soon superseded by one that actual does has a direct tacho signal. It appears my tacho dial is calculated on the circuit inside the CIP itself.
On a brighter note I have managed to configure the blitz's oil pressure signal. I can display oil temp and the boost gauge is good. I have also calibrated the car speed. At least that was easy to wire in. There is a spade connector as shown as the empty "plug C" - 12 pulses per revolution. (P218). All I had to do was run the car at 25 mph and hit the button!
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