Looks like I don't have enough spare pins on the DB37. I there anything I can free up?
2 of the ground pins ?

spr1 fan (JS0)
spr2 vics (JS2)
spr3 EBC (JS11) - I know the code is not working now, but I expect it to be in the future
spr4 alternator control
iac1a CMP
iac1b TS Table Switching (PE1/R1) as failsafe for my WI
iac2a Knock (JS5)
iac2b spark B
?? WI Waterinjection (D15) I could activate this with a pressure switch, but I'd rather do it with the MS (more flexibility)
?? LC Launch Control (PE0/JS7) Seems cool to play with

Glad I don't have a/c or I'd need a 3rd free pin.

BTW, all circuits (fans, vics, ebc, alternator control, TS, knock, WI and LC) can be built in the proto area .

 

I assume IDL(30) and IGN(36) are also in use? Sounds to me like you need to grow beyond the DB37 then. Easiest thing to do would be to knock a hole in one of the side panels and install another connector. A DB9 would fit easily, but require a somewhat complex cutout. If you only need two more pins, you could fit a 1/8" TRS (stereo headphone) jack, and use only the tip and ring terminals. (The sleeve would be grounded through chassis on most designs.)

You could also install a "Molex 093" style panel-mount connector. These take a simple rectangular hole which is easier to make than a DB9 hole with a sheet metal nibbler: Male and female.

 

Problem solved.
I used a chassis mount keyboard connector from an old Pentium 2
Very handy, as the wires are already molded on it.