i recently bought a 91 crx with a blown motor and i have a obd2 motor and trans from an ek swap i did earlier this year. should i use the obd0 harness thats in the car and put new connectors on it, or put a obd2a harness in it and change the the plugs that go to the other harnesses in the car? any wiring diagrams and help will be much appreciated

 

keep the OBD01 sensors and harness. in fact, i wouldn't even swap the intake manifold, keep the stock one.

 

but arnt the connectors to all the sensors different because i had to change some on my b series swap

 

What ECU are you going to run?

If you plan on going away from OBD0, then keep all the engine sensors as they are.
Change out connectors as necessary on your stock harness.
Run an OBD0 to OBD1 jumper harness and an OBD1 ECU.

if you stick with stock OBD0 then you will need to switch some hardware out.
The distributor for sure and maybe the intake manifold depending on what your engine has on it now.

 

its a p2e its the ecu that came out of my dx, i know when i did my other swap i had to connect two wires together because the iac was different and im just gonna keep the cable trans thats in it so i dont have to run a clutch master cylinder, i know what matches up for the motors but im still new at this conversion wiring thing

 

the only thing you need from the ek swap is the long block
block/ head
reuse every thing else from the crx
the crx intake will bolt up and most of the sensors are on the intake.
there is no good reason to use obd2.
also that ek harness is a 1 piece were the crx is a 2 piece
the first rule of engine swaps is to use your stock harness.
the ek tranny is hydro and you rex tranny is cable so reuse the crx tranny.


only wiring modifications you will need to do is extend the coolant temp sensor that is on the back of the crx engine to the thermostat housing on the ek engine.



this is solid advise and will save you a ton of headache if you follow it.

 

like i said, just use the long block, install the old sensors into the head, and use the old intake manifold, no need to rewire anything and fudge with the OBD2 hardware.
that is the simplest, cheapest way. you could also convert to OBD1, with a jumper harness, but i do not see a point to that.

 

i didnt think about doing the long block and putting everything on that. thanks guys for the push in the right direction

 

OBD2 ECU

If you go this route PLEASE do a write-up.
I have yet to see an 88~91 running a stock OBD2 ECU properly without a CEL.
Biggest setback seems to be that OBD2 uses a pressure sensor in the fuel tank.

 

if i was to i wouldve done a right up but i took the other guys advice and switched over all the sensors. I just got it runin about a week ago. the only thing i dont really care for is after i let off the clutch and push it back down and go to put it in reverse it grinds. is this cause the reverse doesnt have a syncro