DME Coding Plug Question
 

I have an 1987 Base model 944 and I am trying to figure out the coding scheme of my computer. According to this site, neither the coding plug nor the impedance adapter is supposed to be used on the US model 944.

However, I checked the plugs on the DME Harness and there was a red jumper adapter installed on the coding plug (Plug found closest to the DME) and the second plug (The longer one found higher up the harness) was not connected to anything. Also, the cable for the altitude box was not connected to anything as well. I believe the previous owner may have installed this jumper plug for some unknown reason.

So my question is would the correct configuration for a US model '87 944 be, coding plug left open (No Jumper) and the second plug connected to the altitude sensor? I live in Albuquerque where the altitude is over 5000 ft so I am assuming the altitude sensor would make quite a difference.

Thanks in anvance for your help.

The altitude sensor makes little difference. It simply leans the fuel out 6% once the car is above 1000 meters. There is no other logic attached to it. You can plug it in and see if you think it's an improvement, but it probably makes no difference at 5000 feet.

Your car should not have either coding plug if it is a US model. The EU coding plug (with the resistor) tells the car to ignore the oxygen sensor and also indicates that there is no cat present. I do not know if the WOT maps are changed to account for the lower backpressure in the exhaust. I would point out that N/As generally don't see much of a performance gain from cat removal, so I doubt if the map is much different.