Hello all,
I recently bought a 88 CRX with the D16z6, Vtec head installed with a p28 ecu ,Zex cam.

I have been doing some research and am confused. The vehicle runs but is seeking at idle. I noticed that there isn't an O2 sensor installed. I found the connection and it is for a 1 wire O2 sensor. I went to the junk yard and found the connectors for a 4 wire male and female. does anyone know where I connect the one wire, and where to run the other 3?

 

those connection are pre-wired through a obd0-obd1 conversion harness at the ecu. if yours did not come with one then you are SOL, you would have to make it yourself.

 

that is what I am looking for, what pin to run what wire too. Everything else has been switched from what I can tell, unless the temp gauge runs through it too. that is also in need of mending.

 

cant you buy these things at an auto parts store? lol

 

https://honda-tech.com/forums/honda-crx-ef-civic-1988-1991-3/d-i-y-faq-obd-0-obd-1-pinouts-conversion-help-1319235/

 

thanks for that thread. read up on it quite a bit.. I haven't even looked at how they did the conversion yet. The seller stated VTEC is working and it has the P28, but they could have just wired the distributor, and RPM guage.. I hope it isn't all messed up..
If so I would think that a 1 wire O2 sensor would be better than no sensor.. thoughts?

 

yeah get a new sensor that has only the plugs that you
have on your car

i just sold my header and let my sensor in the haeder like
retard....\
omg add it to the list.

 

yeah, I think I'll give it a go. It does trouble me that the heat sensor isn't working either, I'll see if I have time to pull the ecu out tonight and take a good look at what they have done so far

 

wire that bastard up lol. here is a diagram i wrote up

 

you have a p28 ecu, which is OBD1. that ecu needs a 4 wire o2 sensor to work properly. the 1 wire sensor will not do any good. have you looked at your ecu yet? how are the chassis ecu plugs connected to the p28. hope they used a jumper harness and didnt hack the sheeet out of everything. blahhhh

 

Hatchet; I hope they didn't too, bad am starting to think they did. 2 things are missing, the O2 and the Water temp.

efjones; so I can wire the 1 to the existing O2 wire, then ground number 2, possibly run 3 to my fan wiring since it is switched, and put 4 into the ECU? is the pin shown is that in the OBD0 pin A6?

thanks guys!

 

No this is only for obd1. Obd0 ecus don't support the heated o2 sensors

 

Here a diagram that katman and I added onto, its how to wire everything up obdI to harness.
ENJOY!
https://honda-tech.com/forums/showth...4#post46225614

 

you do realize you responded to a thread over 6 months old, and your link is 90% useless. the OP's car is an 88-91 civic/crx model and your "write up" only applied to 92-95 civics

 

But the Katman....

 

I hav a 91 honda crx with pr4 obdo ecu ..trying to wire up 4 wire o2 sensor previous owner cut out the plug and wires from harness... question is what pin numbers on ecu do I hook up my 4 wire o2 sensor I never had to wire one up so im just trying to get a little information thanx guys

 

Open the ecu and see if it’s chipped. It could be mapped differently and the o2 deleted. You could be hooking it all up to an ecu that is programmed to run with out it.

 

There were two PR4s
There is an OBD0 which will have just 1 wire for O2 sensor.
There is an OBD1 with the 4 wire.

You said you have an OBD0 PR4 so .... 1 wire O2.

 

Man guys thanks so ,, no chip in the ecu double checked... and I did research and couldn't get it figured so the help is appreciated... so pr4 obdo ecu is what I am using ( so my next question, I can just throw aside 4 wire o2 ???? And just get a single wire o2 sensore and put that in sense the obdo pr4 required only a 1 strand ? ) and I got the ecu wire diagram it says c16 is for o2 sensor does that sound right guys .. if not does anyone know were I can insert the wire from o2 into ECU.. because there no plug for me to ug o2 into its ben completely ripped out by former owner.