working on my ls swap and a little confused on the ecu. i have a 91 EF SI d16a6 coming out and putting in b18a. i got ecu and engine harness. but when looking at wiring the b18a harness will not work with my chassis. so i pulled the harness off me d16a6 and was going to swap onto b18a.

now will this ecu i got with b18a plug/work with my chassis harness? the ecu i have is a 37820-pr4-l10. i did some reading and seen to look for R69 and R70 to determine if its a at or mt and i found R69 with no resistor but cant find R70 for nothing.

 

Are you running OBD0 or 1? You have to use your Si harness because as you found out it won't plug into the cabin and shock tower harness. Depending if you run OBD 1 will determine if you need to do some wiring. And I may be wrong but I thought a PR4 ecu was for vtec. Either way I think a better ecu suited for you would be a P75........then again it depends what OBD you're gonna run.

 

well was going to try and stay obo 0 right now and use stock harness and hopefully just swap out the ecu. i dont know what a p75 is? i really just want to get car up and running then becomes more concerned with alot of rewiring.

i believe the 37820-pr4-l10 was obd 0 in 90-91 then went obd1 in 92. not 100% sure though

 

Your Si harness will plug right onto the b18a with no problems as long as you stay obd 0. Does your ecu have the red led for checking cel codes? If so it is obd 0.

 

The PR4 is available in obd0 and obd1.

you should really read this before continuing:

https://honda-tech.com/forums/honda-crx-ef-civic-1988-1991-3/detailed-b-series-into-crx-ef-civic-parts-list-more-2769325/

It's best to research before diving into the swap, then you would have known that you have to use the D16 harness.

 

actually ive done hella researching just got confused on ecu's i was aware of swaping harness over. just like i know my ecu is a cali ecu which is not the best but as long as it get my car running right now thats my goal.

yes i have the red led. but i thought obd1 had red led as well thanks for clearing that up.

 

Obd1 uses the cel to flash codes, so it doesn't have the led on it.

If you're staying obd0, which it sounds like you are, then the ecu should plug right into your factory plugs and your si harness should swap right onto the engine. I don't believe you should have any real wiring to do.

 

No OBD1 uses the cel to flash the code.

 

oh got yah. thanks for the help.

 

ok ran into a slight snag when installing harness.

on d16 harness there is 2 wire sets that i want to verify.
-red & green= intake temp sensor(round plug)
-blue & black/yellow= coolant temp sensor(flat plug)

on b18 harness
-red & green= intake temp sensor(round plug)
-black/yellow & blue/yellow= coolant temp sensor(round plug)

can someone please verify i have my facts right. ive been tring to search the haynes manual for both motors but seems wiring diagrams are very vague. and it seems like i have to cut off b18 ECT sensor plug and splice onto D16 harness (removing flat 2 wire plug)

 

IAT is a red/wh & grn/wh

Remind me of the location of the coolant temp sensor, I think it's the one on the side of the head, I just want to be sure I'm looking at the right one.

 

on the b18 its on the back by the knock sensor by the alternator. not sure on the d16 i sold that.