Relay Harness Wiring

[Targa44]

... trying to map the wiring from the "Main Plug" connector via the harness to the "Relay Board" connector to the relay board terminal blocks. I wanted to check the continuity of the relay harness and see how it was linked. When going from pin to pin on each side of the harness I found some things that puzzle me.
1) Pin#2 (referenced as the Crank Sensor Shield on the hardware guide) on the ECU side has a bare wire socket on the DB37 and I'm guessing is part of the shielded large white wire contained in the harness. However, there's no corresponding connection on the relay end of the harness - pin#2 is unused. Can't find continuity between pin#2 and anything on the relay side.
Why is that?
2) Pin#7 (Sensor ground) on the ECU side corresponds with pin#8 on the relay side (pwr ground).
3) No link to Pin#8 ECU side to where?
4) A few ECU side grounds are off one notch with the relay side - but it looks like grounds to grounds.
5) Pin#32-33 and 34-35 are crossed between ECU and Relay side - but they stay in the "family" with INJ1 and INJ2.
6) Finally, Pin#36 ECU side is for IGN (high current ignition) and on the relay board is S5 (or #11 on the terminal block) - BUT, my S5 reference shows it for "Coil 1 output" to pin#36. ??

Going to try and attach an Excel spreadsheet to show some of the paths. The items in red are the inconsistencies.

thanks,


kj

[jsmcortina]

The relay board is a very old design from MS1 days. That's why it is not recommended for MS2 or MS3.

James

[Targa44]

Thanks for responding James.

Such is the life for buying a used system (yes, MS3). I've wasted some time, but it's all installed. I'll see if I can "reconfigure" a harness to get the relay board and ECU to be civil again. If I go for a shielded wire for the VR sensor wires (like the DIY harness), would I not keep the bare ground wire for both ends (pin2 to pin2)?

kj

[jsmcortina]

If possible, connect the sensors direct to the MS3 plug, bypassing the relay board.

James

[Targa44]

Okay.
For me, my sensors are 1) MAT / air temp, 2) CLT, 3) Wideband, 4) VR crankfire.

However, the MS3 plug only seems to have (2) sensor ground plugs - Pin#1 and Pin#7. Do I combine a few things to keep it routed to a "sensor" ground pin? I'm referring to the Hardware Guide for the main plug. Isn't there still a distinction between "power grounds" and "sensor grounds"? The wideband (AEM) has only 1 ground wire and it's been recommended to go to the battery with that. Otherwise I can combine MAT/CLT returns to one pin with VR going to pin#1.


thanks,

kj

[jsmcortina]

I can combine MAT/CLT returns to one pin with VR going to pin#1.

Sounds good.
TPS too.

James