1990 GS to GSR Need Help

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Junior Member
Hey Guys

Heres the deal I got a 1990 GS with an b18a engine in it, and I just bought a totaled 1993 GSR with the B17a motor in it and i want to switch it over, and i have a few questions. First do i need to use the p61 ecu or will the ecu in my car work. Next one is do I have to rewire the distributor or just plug in the harness that is on the gsr to my cannon plugs on the firewall and just wire in the vtec. And Do i have to remove the fuel injector resistor pack on the gs. I just wondering what i need to do to move this over or would it be easier to move the whole wiring harness out of the other car and use the p61 ecu. And I imagine the gsr will have a four wire o2 so that will have to be changed too. I don't think my plugs on my ecu will fit on the p61 because the p61 looks bigger.

Anyway any info would be a big help.


Senior Member
You'll need to run the GSR ECU. Your stock harness will not plug into the p61, so you'll need to either make or buy an OBD0 to OBD1 harness. You can buy them at http://rywire.com and http://hasport.com. You'll need to wire the distributor for OBD1 also.

Don't just put the GSR harness in your car, rewire your stock harness, it will be MUCH easier. You'll also have to run the wiring for VTEC (should only be 4 wires, but I've never done it in OBD1, so I'm not sure). Other than that, you should be good.

I don't know anything about the resistor pack or the 4-wire o2, so someone else will have to tackle those.


Senior Member
yea the resistor box needs to be taken out and u jus need to sauder in the new injectors and take the 4 red a n black wires and the one yellow wire goin into the resistor box and sauder all the red and black wires to the yellow wire, and as for the 4 wire o2 u have to wire that in 2. i'm pretty sure when u buy the harness adapter it will come with a pigtail to wire in all the new things u need. if not then u need to get one to make everything simple.