the_crowbar

Greetings all,

The short version of the question(read on for the full info):

D16y8 swapped into 92 hatch. O2 sensor replaced with new (non oem from Napa). When engine is cold it runs great. Once engine warms has little power below 3000rpm. CEL code 1 (O2) thrown occassionally. Registering ~ .35-.50 volts betweeen signal wire of O2 and ground. Any ideas what to check from here?

The long version of the story:

I recently helped a friend swap a D16y8 into a 92 hatch. The ECU was replace w/ a P28. The D16y8 had come from an automatic and instead of converting the IACV the intake/TB was replaced with one from a 95 crx manual. The old engine had a 1-wire O2 sensor, so new wires were run from the shock tower plug(s) to the o2 sensor plug. (Even used a shielded piece of wire from another harness for the signal wire.)

The D16y8 o2 sensor was used at first. The car ran great when cold. Once the engine warmed up the car has no power. It "feels" slower than with the original CX motor. Was getting a CEL 1 (o2 sensor).

Sensor was replaced by one from Napa (not oem, but came with oem matching plug.). Car still slow and throwing o2 code. Checked all wiring (soldered connections), checked pinout locations (all correct), checked signal from o2 sensor (reading ~ .35-.50 volts to ground with car warm and running).

Any ideas what to check from here? I am running out of ideas.

Thanks,
the_crowbar

the_crowbar

Since no one has answered yet I have a couple related questions to ask.

1) Would the exhaust be a possible cause of O2 sensor problems? The civic has a DX badge on it, but the engine pulled was the CX motor. The exhaust from a CX is ridiculously small.

2) Can the placement of the O2 sensor affect its readings? The CX has a one wire O2 sensor that sits right next to the block. From some reading I have done I think the O2 may be too close to the engine and not able to read a signal from all four cylinders. On a DX/EX/VX engine how far from the block is the O2 sensor?

Thanks,
the_crowbar