MC-2 Wiring Questions (Engine Transplant)

urq urq at
Thu Oct 11 10:42:09 PDT 2007

I spent a very fruitful couple hours with the wiring diagrams for a 1990 200 working out what wires I will need to hook up to get the MC engine running in my '83 urq.  All in all there are only a handful of wires I'll need to connect ... but there were a couple questions I had which I thought I'd post to see if anyone had answers ... 

There are several wires that go back and forth between the Idle Stabilizer Control module and the A/C Control Head.  I am planning to leave them open for now, but I suspect one of them can take the signal indicating that the clutch is engaged so the Idle can be compensated.  Perhaps one of the others is a signal to tell the A/C to disengage the clutch.  

There's a connector in the shower cap for the ECU connector which is T6g in the wiring diagram.  This looks like the place you tell the ECU about the car ... AT vs MT, California model, etc.)  There is no information about the definitions in the wiring diagrams, so I thought I'd ask if anyone knew which pins did what.  

There's another 6 pin connector which has all the signals for the trip computer ... T6f if memory serves.  I'm hoping that these signals will be compatible with the digidash when I get around to installing it (or a Coupe/4k analog dash with trip computer).  Has anyone tried that link out on the MAC-14?

The ECU feeds a tach signal out for the instrument cluster, but the urq's wire goes to the primary on the coil.  It looks like there's an analagous pin on the MC's ignition coil, so I'm going to try there first.  

One thought for those of you who pull wiring harnesses out of cars to sell them is to consider hacking the wires on the other side of the mating connector (assuming you're not going to pull that for sale too).  That way the user of the harness will have a connector they can wire up for the project car to make it look factory.  I'm going to hit a PnP here in the next couple days to see if I can find what I need, but I suspect I'll have to splice into the harness I have.  

Steve B
San Jose, CA (USA)

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