Another high NOx thread

Phil · Feb 17, 2006

Failed smog today.

'94 XJ 4.0L
4.88s in the diffs, 35" tires
Turbo City air tube, Banks header
replaced cap, rotor, plugs, wires a couple weekends ago

Searching, it looked like some people say a dieing cat causes high NOx, some say running lean.

I had 14.8% CO2, 0.2% O2. My HC and CO emsissions were within the limit, but NO failed at 15MPH (623 ppm / 517 max) and was close at 25 MPH (724 / 770).

I'm inclined to blame my cat, as it got some loving from rocks over the summer, but is there anything else I should look at?

Thanks.

ZomBrady · Feb 17, 2006

Phil said:
Failed smog today.

'94 XJ 4.0L
4.88s in the diffs, 35" tires
Turbo City air tube, Banks header
replaced cap, rotor, plugs, wires a couple weekends ago

Searching, it looked like some people say a dieing cat causes high NOx, some say running lean.

I had 14.8% CO2, 0.2% O2. My HC and CO emsissions were within the limit, but NO failed at 15MPH (623 ppm / 517 max) and was close at 25 MPH (724 / 770).

I'm inclined to blame my cat, as it got some loving from rocks over the summer, but is there anything else I should look at?

Thanks.

That's a failing catelytic converter for you. . . switch it out and you'll be fine.

carnuck · Feb 18, 2006

If the readings go higher, make sure you have factory spark plugs for your engine! 1 heat range hotter will jack the numbers like crazy!

johnnyc · Feb 18, 2006

Agreed on the cat.

Remi's dad's XJ failed for the same reason. A new cat later, and it passed.

Another high NOx thread

Phil

NAXJA Member

ZomBrady

Chubby Chaser Extraordinaire

carnuck

NAXJA Forum User

johnnyc

NAXJA Forum User

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