I am in the final stages of drawing up my wiring diagram for Megasquirt MS3X on a 3.6 engine going into my '88 Carrera and I have a few queries that I haven’t been able to figure out. Naturally, I have raised these on the MS forum, but there is next to no traffic there on MS3X issues so I thought I’d come back home to Pelican and try my luck.
Tacho Wiring
Can anyone clarify how they wired up their tacho to MS3X?
5V Sensor Supply
I have three sensors requiring 5V power - cam position, ignition timing and TPS.
Can I use the main board DB37 pin 26 to supply all three?
O2 Sensors & LC-1
Pin 23 on main board DB37 connector is for O2 sensor. Where would I connect a second O2 sensor input?
Grounds
I am planning to join the grounds from both DB37 connectors and run one fat (2.8mm2) wire from each connector to the main engine ground. However, I remember reading somewhere that all 0.5mm ground wires from each connector should be run all the way to the main engine ground, but this starts to get a bit messy when there is something like sixteen wires all fighting for space at this point.
What is the problem with joining the small grounds and running one main wire from each DB37 connector (as in my wiring diagram)? Please tell me it will be OK!
I have attached a copy of my wiring diagram but the detail is too fuzzy to see in a jpeg file. It’s not quite final yet, but I am happy to email a clear PDF version to anyone who is interested to review and comment on it. (Click on my name for email.) The yellow items are OE parts. Quite happy to get some feedback from others who have already done it.
