Hey guys. I'm doing a 97 OBD2a GSR swap into a 2000 DX Civic Hatch and I am currently working on the wiring. I'm using the original SOHC harness, but modifying the length of some of the wiring to the plugs.

Besides adding the traditional wires like the knock sensor, the VTEC oil pressure sensor and the VTEC Solenoid as all swaps require, how do you wire the 3 pin Crank Angle Sensor plug from the SOHC to the GSR's 2 pin connector? I know there's a bypass trick but I was wondering about actually making it functional instead of just ignoring it.

In Addition, since the GSR's have the secondary butterfly’s in the manifold I need to wire that to the ecu. Sound's good right?

The oxygen sensor...the SOHC has two plugs; The GSR will only use one. Which one of the two plugs do I use?

 

In Addition, since the GSR's have the secondary butterfly’s in the manifold I need to wire that to the ecu. Sound's good right?
-yes, it needs to be wired to the ECU
The oxygen sensor...the SOHC has two plugs; The GSR will only use one. Which one of the two plugs do I use?
-Use the plug that ran to the upper O2 sensor (the first one the exhaust gasses run into).

Sorry i cant help you with the crank sensor, my engine/ecu didn't have one. Hope this helps.

 

Awesome! Thanks for the info

 

if you use a obd2a-obd1 and run an obd1 ecu you won't need that CPS and a few other sensors.. it's up to you

 

convert to OBD1. youll save yourself a lot of headaches and all most of the engine managements are for OBD1. if you keep it OBD2 you may also need to install a fuel tank pressure sensor depending on ecu. OBD1 much easier.

 

i dont think the second o2 sensor is an o2 sensor at all. i think its an exhaust gas temp sensor. i mean everyone calls it a secondary o2 but if you have ever pulled it out and looked at it, its clearly just a temp probe.

anyone else ever notice that?

 

OBD2 uses 2 O2 sensors...one before the catalytic converter and one after. Neither of them are EGT probes.

 

correct. second o2 checks to make sure the catalytic converter is doing its job.

 

Thanks guys, Very good info! I'll post a pic of this swap when I'm done.

 

dont forget to wire your iacv...

 

ok i put a sir obd1 engine in my 99 ej that i converted to obd2.for the crank speed sensor that is 3 wire down further there is only 2 wires blue and white cut the sohc sensor off and soder on the dohc sensor and you will be fin the 3rd wire is like a magetic field of some sort but if u cut it lower its already spliced and done for u. and yes my obd2 port works my car runs just as if it was a 99 si

 

o and for the ppl that r going to say why did i convert it to obd2. i did it so i could pass emissions and i did.

 

Yupyup, thanks guys. I also realized that I am using an OBD1 ECU so I wont even have to bother with the crank angle sensor by the crank pully.

 

have you ever physically held the 2 of them in your hands? t he front one is clearly an o2 sensor. the rear looks nothing like it. maybe its because my car is JDM, who knows. but there is no way in hell the second sensor behind my cat is an O2 sensor. unless a plain steel rod with only ONE wire coming from it can somehow measure oxygen/hydrocarbons.

 

Yeah I gotcha, the second sensor is clearly not an O2 sensor, just some sort of a sensor to check on the cat I guess. None the less it's a product of the OBD2 cleaner air system.

 

i belive its a egt senor to see if the cat is still good and in working order if your cat was hollowed out or a straight pipe the egt will pick up on it becasue the gasses would be at higher temp then normal

 

Very much correct, its just a heated sensor. I have a 96 JDM ITR and I have that 'probe' thing as well. I've had other OBD2 civics (JDM) with the same 'probe' also.
Whether you have a catalytic converter or not it works and will only throw a dash light when no exhaust gas is flowing. How do I know this? My 96 R came with a 'fake' cat (hollow inner pipe) and I never got a light. Only got the light when the sensor was not screwed into the exhaust.

The OP might have a real O2 though as I think that probe is specific to JDM cars.

 

yes only jdm specific. my 99 civic has a regular o2 sensor in the rear.

 

Before the 4-wire "heated" O2 sensor came along, there were indeed 1-wire models that relied on the exhaust gas to heat it up to operating temp.