ok i have a 95 civic dx with a d16y7. it is still running the ecu from the origional auto d15. my question is, will the d15 ecu cause bad gas milage by causing it to run too rich? because I'm getting like 25 mpg and it smells like its running rich. any help would be great.

thanks, Justin

 

If memory serves me correctly, the d16Y7 is an OBDII system where the ecu for the d15 is an OBDI system. What do you have for O2 sensors hooked up?

 

it has an obd1 conversion

 

h: I don't know then. I would start with replacing the O2 sensor. O2 sensors are meant to fail in such a way that when they do, they will make the car run rich instead of lean.

 

i got the same setup as you.. 94 coupe, d15b7, and i get about 28 mpg in the city while revving the shit out of my motor. i get about 33 combined if i drive normally.