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Wiring questions: OBD2b B20 engine into OBD2a EK Civic DX
I'm looking for help/advice on wiring changes I'll have to make on an upcoming swap: I'm planning on swapping a 1999-2001 high compression B20 into my 1998 Civic DX. I have picked up a few parts that I will be bolting to the B20:
-B18b OBD2a intake manifold, to include throttle body, fuel rail, injectors, IACV, etc.
-Integra LS OBD2a ECU
I'm aware of the IACV 2-wire conversion I'll need to do, as well as the CKF trick to avoid throwing a CEL. I'm trying to prepare as much as possible by picking up everything I'll need to perform the swap (I already have a transmission, axles, radiator hoses, shift linkage, brackets, etc).
My concern is wiring. I was planning on using my stock OBD2a wiring harness. What wiring and/or plug changes am I going to have to make to get everything to work correctly? Does it matter which distributor I run? I'll attach a couple of pictures of my OEM distributor plug for reference. Any connectors/plugs or parts I should pick up beforehand to help this swap go smoothly?
Any advice and experience is much appreciated! Thank you!
Re: Wiring questions: OBD2b B20 engine into OBD2a EK Civic DX
It looks like the 99-01 CRV engines use a rectangular distributor plug and my OBD2a EK uses a square plug. Since I’m sticking with an OBD2a ECU/setup, should I just buy an OBD2a LS distributor to simplify things? I’m assuming it would just bolt onto the OBD2b B20B/Z head?
Re: Wiring questions: OBD2b B20 engine into OBD2a EK Civic DX
From what I can tell, it looks like all 96-98 Civics, 94-01 Integra’s and 99-00 EM1 Si B16 have the square 10-pin distributor plug.
The 99-01 CRV (and 99-00 EX) has a rectangular 8-pin distributor plug. From what I’ve been reading the extra wire(s) on the 10-pin plug are RPM signal… so I think if I used a cheap 10-pin to 8-pin conversion harness, I don’t think my tach would receive the signal.
My question is: since the B18b and 99-01 CRV B20b/z/z2 all use the same P75 head, can I just bolt on a 10-pin distributor from a B18b? Will it just work?
Re: Wiring questions: OBD2b B20 engine into OBD2a EK Civic DX
To make things easy, just use a '96-99 Integra LS distributor. You can use the CKF on the B20 (you don't have to do the "CKF trick"... you will simply have to convert the 3-wire "D" series connector to the 2-wire "B" series connector. De-pin the 3-wires from the plug, tape off the brown/black wire, and match the blue/red and the white/red wires to the same position in the new 2-wire plug corresponding to the plug on the CKF sensor on the B20 engine. Fuel injectors, ECT, coolant gauge plug, fan switch, and alternator wiring will all work. You will need to open up the engine harness where the TPS, IACV and MAP plugs are... pull all of this out of the main bundle there far enough that you can re-direct them with enough slack to reach the T/B on the LS intake manifold, and then loom and tape everything back up nice. Lastly, de-pin the 3-wire IACV plug clip, tape back the orange/black wire, and place the two remaining wires (black/yellow and blue/black) into a correct round 2-pin connector for the 2-wire IACV. Don't forget to move the blue/black wire at the ECU plugs from position A14 to A12 and de-pin the orange/black wire at A13. Good luck.
Re: Wiring questions: OBD2b B20 engine into OBD2a EK Civic DX
Originally Posted by JRCivic1
To make things easy, just use a '96-99 Integra LS distributor. You can use the CKF on the B20 (you don't have to do the "CKF trick"... you will simply have to convert the 3-wire "D" series connector to the 2-wire "B" series connector. De-pin the 3-wires from the plug, tape off the brown/black wire, and match the blue/red and the white/red wires to the same position in the new 2-wire plug corresponding to the plug on the CKF sensor on the B20 engine. Fuel injectors, ECT, coolant gauge plug, fan switch, and alternator wiring will all work. You will need to open up the engine harness where the TPS, IACV and MAP plugs are... pull all of this out of the main bundle there far enough that you can re-direct them with enough slack to reach the T/B on the LS intake manifold, and then loom and tape everything back up nice. Lastly, de-pin the 3-wire IACV plug clip, tape back the orange/black wire, and place the two remaining wires (black/yellow and blue/black) into a correct round 2-pin connector for the 2-wire IACV. Don't forget to move the blue/black wire at the ECU plugs from position A14 to A12 and de-pin the orange/black wire at A13. Good luck.
Thanks for the feedback, I appreciate it and will put it to good use!
You'll also need to run the wires for the secondary O2S to the back of the converter under the car, since the original for your Y7 is in the engine loom and plugs up under the close coupled converter.
You can accomplish this with an extender harness that plugs in at both ends and a bunch of zip ties to route it to the back of the new converter, or you can open up the factory grommet location (ahead of the shifter on the tunnel) with a hole saw and run the wires across the floor to c131 (green connector near the ecu) as factory.
Definitely find yourself a .pdf of the 96-00 Helm manual and study the wiring. It's not terribly complicated.
You'll also need to run the wires for the secondary O2S to the back of the converter under the car, since the original for your Y7 is in the engine loom and plugs up under the close coupled converter.
You can accomplish this with an extender harness that plugs in at both ends and a bunch of zip ties to route it to the back of the new converter, or you can open up the factory grommet location (ahead of the shifter on the tunnel) with a hole saw and run the wires across the floor to c131 (green connector near the ecu) as factory.
Definitely find yourself a .pdf of the 96-00 Helm manual and study the wiring. It's not terribly complicated.
I knew about the secondary O2 and was planning on running an extender for it.
I also have a Helm’s manual out in the garage and found a couple FF-squad articles that help with some of the wiring. It looks pretty straightforward:
You'll also need to run the wires for the secondary O2S to the back of the converter under the car, since the original for your Y7 is in the engine loom and plugs up under the close coupled converter.
You can accomplish this with an extender harness that plugs in at both ends and a bunch of zip ties to route it to the back of the new converter, or you can open up the factory grommet location (ahead of the shifter on the tunnel) with a hole saw and run the wires across the floor to c131 (green connector near the ecu) as factory.
Definitely find yourself a .pdf of the 96-00 Helm manual and study the wiring. It's not terribly complicated.
Good catch spAdam... I forgot about that part. Thank you for cleaning up my sloppy answer.
Wiring questions: OBD2b B20 engine into OBD2a EK Civic DX
