I currently installed a 99 civic SI in my 96 DX civic coupe.....I used everything like to wiring harness and ecu. I am having problem with the aftermarket fuel pump not shuting of when car is not running but key is turned on, also check engine light but no codes are showing when wire is jumped, not working speedometer....Oh and does anyone have the wiring diagram to the ecu for the 99 civic SI also the stock timing.

 

Did you use the harness from the 99 Si? If so, that is probably your problem, you need to use the harness from the 96 because the plugs are slightly different than the 99-00 cars. If you want to use the 99 ECU, you have to get an OBD2a-OBD2b jumper harness. The 99 harness has an extra plug that connects to the gauge cluster that the 96-98 doesn't have. Let me guess, your gauges probably aren't working correctly either?? The fuel pump should turn on with the key on the ON position, that is normal, but I think you're going to have to put the 96 harness in and wire the necessary VTEC wires for your motor. And run the jumper, or else you will keep running into problems.

 

I agree with AzSi22!

 

Hey thats what I was expecting and the wiring is a bit confusing to go and redo it so I am just going to use the existing harness that I had the stock 96 harness. Thanks for the info.