When you do a dpfi to mpfi swap do you need a different o2 sensor or something? Ever since I did that swap i've had code 1 coming up. If i turn off the car and turn it right back on it resets the code for a little bit. this is my 3rd sensor surely they cant all be failing. Has anyone else had this problem? Is it likely caused by the swap? It looses alot of performance when the light comes on otherwise i wouldnt be too worried. Please let me know if i'm missing something. Idid all the checks in the haynes manual. what else shouldi do?? oh and i have an 90 crx dx

 

i don't think you need a different o2 sensor. i think all obd0's are the same. pretty sure anyway. are you trying new sensors, or used sensors. if all are used, you might just be having bad luck.

 

theyre all the same. the only youll need to change it is when you convert to OBD1

 

Perhaps there is a REASON the sensor is tripping. They're not just put in there to fail, they tell you when your exhaust emissions have exceeded parameters.

Is your timing off?

Vacuum Leak?

Map Sensor?

 

I once had this problem on my 88 CRX Si and it turned out to be an issue with the harness. I wired the 02 sensor directly to the ECU and the code never came back.

 

If this was the case, then resetting the ECU wouldn't shake the code. It would a permanent break in the circuit.

 

I had this problem with my car. It wasn't the O2 sensor, the wiring or any other mechanical problem. I had the incorrect ECU in my vehicle. In my case I had a CRX HF computer which is intended for a different O2 sensor, than the normal CRX Si (PM6 or PM7) ECU. A simple check on the side of the ECU should tell you if this is the case.

If that doesn't work I would get a voltmeter and check to see if the oxygen sensor is producing some voltage when the vehicle is running. Then I would make sure that there is continuity between the O2 sensor connector and the pin on the ECU.

 

I don't know how to attach a link, but if you look up my posts that I started you will see what I did to fix my problem that is like yours. Not all may apply but some of it will.
I was able to link the post.
Try this
https://honda-tech.com/forums/honda-crx-ef-civic-1988-1991-3/dpfi-mpfi-swap-code-4-code-1-how-i-caused-them-how-i-fixed-them-2026931/

 

Resetting the ECU would always clear up the code temporarily for me too. Then after a bit of driving, the CEL would pop up.