misternguyen

Hey I have a 95 cx honda civic hatchback with a 97 obd2 gsr engine in it. My car right now runs but the VTEC does not kick in right??? I'm thinking that the wiring could be wrong. I was just going to switch up the wiring harnesses. Which one should I use??? OBD2 TO OBD1 or should I just stick with the regular factory one??? I have a p72 obd1 ecu right now. Really need some help to get my car running right. ANYONE??

klungemonger

You don't need any sort of "OBD2-OBD1" harness. You have the correct ecu also.

Did you run wires for VTEC solenoid/knock sensor/secondary IAB's in the chassis side of the engine harness? Not the harness that goes on the engine itself, the part that goes into the ecu. I'm not saying you must, because some non-VTEC Civics had solenoid wiring in the harness anyways, but not all models so you need to check and make sure you have all the wiring (if you haven't already.)

Because really there is nothing especially different about installing an OBD2 motor vs. the same motor OBD1 into an OBD1 car as long as you use an OBD1 ecu.

misternguyen

Well I bought the car with the motor already swapped. The swap doesn't look clean. Wires are EVERYWHERE! I looked at the vtec solenoid and theres a wire running from that all the way back to the ecu. Is it suppose to be like that???

klungemonger

Ahhh...so you inherited someones disaster then. That's a shame, because really with a little care & patience the wiring aspects of a typical swap are not that difficult and certainly don't need to look like spaghetti.

Personally if the engine harness looks like crap, just get another clean GSR harness that way you nave no need to modify the engine side it will all plug right in.

Well it also takes 3 wires to run the solenoid...the solenoid single wire, and the signal & ground for the oil pressure sensor. And I'm not totally sure on this but it's possible if there is no knock sensor hooked up VTEC mignt not activate either. There's no need to run directly from engine sensors to the ecu if you have the correct engine harness. You would just run them from the connectors on the shock tower to the ecu connectors.
Definitely sounds like an electrical issue though, it's really difficult to trace out problems caused by someone else's idiocy. Best to just start from scratch and do what you know is correct.