Spitzehare

throwing code 41, primary oxygen sensor, heater circuit. already changed the sensor. still throwing the code. any thoughts?

thermal

What year, make, model Honda?

Fabrik8

If its not the sensor, its usually the wiring. If its not the wiring, its usually the ECU.

civichatch1

did you reset the ecu?

Spitzehare

88 honda crx si with 95 usdm del sol b16a3.
wiring by hasport, also locash racing conversion harness (the one hasport reccomended).

yes i reset the ecu, many many times. it shows the code with the p30 that came with the swap, as well as with a p28 from a del sol si sohc.

ironically, i also have a 94 civic ex auto daily driver that just turned the exact same code on, and i really dont wanna spend $200+ on a sensor if something else is wrong with this one.

the one in the 88crx will soon be swapped into a 93 del sol si, and im hoping the new wires will leave me with just a knock sensor code, but i want to prepare myself for what problem may still be there if the wiring doesnt end up being the problem.