The EHA is adjustable. Mine ohmed at about 20, so I played with the adjustment to see if I could get rid of my rich idle. What I thought was odd was that leaning out the EHA adjustment leaned out the entire rev range. When I used the idle adjust screw to get the mixture correct at higher revs, I was right back to 9 to 1. I did test the O2 sensor and found it bad. When I reinstalled I got a no TD signal voltage at #3 of X11. I pulled the MAS box and the control unit to check continuity and found that the pin I needed on the control unit did not exist. I plugged it all back together and now I don’t have fuel pressure. I removed the MAS control unit and plugged it back in, still no fuel. Pulled the O2 and EHA leads to go to open loop and still no fuel.

The fuel pump relay is built into the MAS control unit, correct? Any way to test the unit out of the car?

I also found the IAT sensor was bad (open circuit), so it was replaced prior to all the above. I guess that was the reason for the high voltage at #3 of X11 right off the bat, though it didn’t really match up at 80%. Will two faults add up at #3, or will it just give the highest faults first?