picked up a b18 swapped 89 civic si hatch w/ an obd1 conversion tuck harness, i am gonna swap the b18 into my 88 crx si and run obd0 for now, BUT i am gonna tuck and shave later on, i am wondering if the tuck harness from the 89 civic si will plug right up to my 88 crx si. do the big plugs that conect the main harness to the engine harness have the same pins? i cant seem to find any pinouts for the main harness to engine harness plugs. any help is appreciated! thats alot, hopefully there are some answers on here in the morning, i am going to bed. goodnight guys.

 

at the driver's side engine to chassis harness connection, the 89 Si engine harness has a round 8-wire connector - the 88 Si chassis harness has a rectangular 6-wire connector at this location - the 89 engine harness will not plug into the 88 chassis harness - you need to swap a matching connector onto one of the harnesses, either a round 8-wire onto the chassis harness or a rectangular 6-wire onto the engine harness - the difference between the two harnesses is due to the 89-91 Si having a Fast Idle Control Valve which the 88 doesn't have, hence the 2 additional wires - you will only need the 6 wires that are on the chassis side of the connector - just match them up color for color - should be Red, Brown, Yellow, Light Blue, Blue with Yellow stripe and Yellow with Black stripe - the 2 wires on the 89 harness that aren't needed are Black with Yellow Stripe and Darker Blue - the 88 Si connector looks like this: