I have one left over wire from my motor swap that I'm 99% sure is an O2 wire. I installed a d15Z1 in my 1990 MPFI CRX for fuel economy and im throwing a code for the O2 sensor. Is this the O2 wire? If so how do I connect it to my boomslang harness to turn the code off. I'm only getting around 40MPG's which is not where I should be, I was hoping to be closer to 50 and I think this is my issue. Any help is appreciated.

 

o2 wire. what boomslang harness? ecu or whole engine harness? if its obd1, convert to o1 o2 sensor and wire it in to the extra wires from the ecu jumper harness. if its an engine harness, shouldnt it already be attached to that in which all you have to do is run the obd0 o2 sensor?

 

That's my question. Also, look at your old exhaust manifold or whever they O2 sensor was and see if it matches up to that plug. That looks like the plug I had on my D15. I would say it may be the O2 sensor.

 

I have the boomslang OBD0 to OBD1 harness version 1.5. It's a small 8" jumper for the ECU. I would look at the old manifold but that is long gone and the motor I bought came with a DC header and the only spot for an O2 sensor is the one behind the block.

Will I need to go out and buy a new one wire O2 sensor and bung to weld and install on the DC header or can I just solder it to one of the current O2 wires going to the OBD1 o2 sensor?

 

Do you have an O2 sensor in your exhaust because what you typed here is not clear.

Yes, you can buy a new 1-wire O2 sensor and weld a bung into the DC header. It will throw a code 41 for Oxygen sensor heater circuit since you don't have a 4-wire O2 sensor.

Can you solder what to the current O2 wires? The plug? What do you plan on accomplishing. You can wire the O2 sensor in your DC header, if there is one, to the OBD1 harness you have.

 

Right now I have a 5 wire o2 sensor (black, grey, white, blue & Yellow). This is what I assume is stock on a '94 D15Z1...

 

Hm. Where is it wired now? One side goes to the O2 sensor right? The other side goes...? You have to have it wired correctly. I'm no expert on 5-wire O2 sensors.

 

The plug and wire you have on the first picture is the single wire O2 sensor "signal" wire.
You need to figure out which ECU you are using so you can find out where the O2 signal input goes.

 

What ECU are you running? I am assuming you have the HX ECU for your engine.
I don't know of any OBD0 to OBD1 jumper that supports the 5 wire O2.
You will have to wire it in yourself.

If you have the HX ECU then you need to wire like this



Here is so more important info regarding the LAF sensor (5 wire more precise version of the O2 sensor).
https://honda-tech.com/forums/honda-civic-del-sol-1992-2000-1/d15z1-ecu-code-48-a-2925409/

Take extra notice the extra wires that run from the harness.

 

So how many O2 signals does a 5 wire O2 have?... 2? Do they have a logic/polarity?
I have never wired one, 4 is the most I have messed with.

 

Two signals and two heaters.
Heaters don't have polarity, but the ECU sends the + side. (Harness provides grounds.)
The other 3 wires are all sensor outputs.

It's not really an O2 sensor that you are used to.
Check out this powerpoint for detailed description of how it works.
https://www.google.com/url?sa=t&rct=...u81j9EhyEunSeA