[Diy_efi] ECM for 1990 Nissan 240

[J]

EGR and canister purge can both be disabled in the programming.  It's a 
simple matter of setting the thresholds to an unattainable level (i.e. 
minimum intake air temp. for EGR enable can be set to 300+ degrees F.)

The idle controls will be tricky at best.  My first thought is to fab a Gm 
IAC onto the engine, but that will likely be quite difficult.  You could 
change the code to work with a PWM IAC, and use the canister purge PWM 
output to drive it, but that means extensive operational code 
changes.....waaaaay beyond the abilities of all but a few.