ok so im having trouble trying to find the right o2sensor
the original engine in my 99 accord was a f23a4 with ULEV the exhaust manifold is different then a f23a1 how ever I did a engine swap to a f23a jdm
I was wondering what sensor should I be using the one for ULEV or the stock one ( I did not swap ecu)

 

read posting rules. No posting in DIY forum.

You need to describe what sensor forward Oxygen (fuel/air) sensor, or other?

I recollect the forward oxygen sensor is a fuel/air mix sensor (more expensive than O2 senso).
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good luck

 

upstream one in the front
thanks for the help your my hero

 

When the swap was done, which O2 was put into the car? When the swap was done there were NO codes afterwards?

 

I had the one from the f23a4 ulev model
it was good up in till 2 days ago I did the swap a few months back

 

you should use whatever 02 sensor the car was originally equipped with, the computer has those parameters programmed in for that specific sensor.

 

Yeah, the car was originally equipped with the F23A4 (ULEV) engine and he kept that ECU. That's the O2 sensor he used, so the sensor is compatible and didn't throw a CEL immediately.

But maybe subtle differences in the JDM F23A are causing it? The exhaust manifold is the obvious difference, but I don't know if there's anything else different (cam profiles, etc?)

 

sensor could have just gone bad too...nothing more nothing less

 

ya i replaced it with the correct one ULEV MODEL and its oem denso and did not like that at all it ran even worse