i was wondering if there are any major differences in the HF wiring harness in comparison to the SI harness on the 88-91 models that would cause any problems in converting from HF to SI, i am about to do this and just needed some heads up from those who have done this conversion at some time, thanks

 

no it should just be plug and play, considering that the HF is already mpfi you should be set to go

 

I just swapped a B18 into my 90 HF. I had to cut wires B9 & B11 at the ECU plug to make the check engine light to go out. I am using a 90 PR4 (Integra)ECU. These two wires are HF only and can freek out any other ECU. Everything else is plug and play. Just leave the EGR plug disconnected at the engine. You may need to lengthen some wires because sensors may be in a different place. I used my 90 HF harness.
HTH
chris