Help! Can't pass PDX DEQ...

[obaa-xj]

Dredging from the grave....
Just FYI and thanks to everyone for their help. Swapping out the O2 sensor brought down the HC to passing levels, but the CO was about double the limit. (I ohm'ed the sensor, and it looked like the heater element must have died in it. So a Bosch lasts about 2 years....). I then swapped out the cat, and wow, what a diff.

HC - 101ppm (limit 220ppm)
CO - .347% (limit 1%)

The CO was over at idle, but the 2nd idle (2500) passed, so they said the cat probably got cold while waiting. So now this rig is back on the road...

 

[Avanteone]

FWIW, the new Cat. Conv. may have COVERED your problem, but it didn't repair it. You still have something causing it to run rich. I don't know how many XJ's I've had or helped on that passed the CO test with no cat. conv. installed at all.

 

[NW-ZJ-SCOTT]

FWIW, the new Cat. Conv. may have COVERED your problem, but it didn't repair it. You still have something causing it to run rich. I don't know how many XJ's I've had or helped on that passed the CO test with no cat. conv. installed at all.

My thoughts exactly..

To add to that, If you ARE just masking the real problem, it will burn up the new cat like the last one.. Catalytic converters generally last the life of the vehicle if the vehicle is maintained and running properly.(with exceptions..of course) But running rich will raise carbon levels and burn out the cat.

Atleast you passed!

 

[obaa-xj]

Yeah, I agree there's probably something real going on. But, it did pass and I got my tags! I know the motor is tired and has some blowby, but there's an ongoing stroker project in the garage, so I don't want to over-analyze this at a shop (read $$) at this point when they're probably just going to tell me to replace the cat anyway.
My intent is swap the old cat back in, and save the new one for when I put in the stroker. I pretty much have all the pieces for the stroker. I just need to find a reputable shop for the block/head work, and a cam which will let me pass DEQ.