Failed NOx reading - Air Care

[ehmyu]

Hi All,
I have a 97 LR Disco I and failed my NOx reading for air care. I am wondering if anyone knew of any way(s) to inprove my results. I am on a limited budget and would appreciated any help or feedback with this matter.

Thanks in advance!
Eddy

[John]

Could be running too lean, could be a failing catalytic converter. If you are short on funds then the best way to fix it is to take it to a knowledgeable service center (many listed on this site under the "SUPPORT" tab) and have it correctly diagnosed.

[PaulC]

Hi
Are you by chance running taller chunkier tires?

I’m off to AirCare today, but 4 years ago I popped into AirCare with my 245/75-16 MTR’s and failed?

I went home puzzled as heck knowing my 98 Discovery was in good running condition.

So I got the jack out (no not Daniels) and installed my 235/75-16 BFG All Terrains.....drove back to AirCare and passed.

About the same time another Discovery owner with crazy swamper type (not tall but wide and super chunky tread) tires, failed....changed to stock-ish tire then passed.

So if I get a fail this morning I guess I’ll swap on the BFG MT and see if I pass. :roll:

[PaulC]

Passed :) No driving/dyno test this time just OBD. :idea:

[chilliwack]

I've a 96 disco, failed NOx as well. I had 250K on the original O2 sensors. Replaced all four, new plugs & wires (they were overdue too!) and passed no problem.

Apparently, the two O2 sensors after the cats just monitor the cat condition, and don't affect engine tune. So you might want to try replacing just the forward ones....... :?

Definitely get the vehicle scanned. When I had mine done, I found out the LH aft O2 had a open circuit on the heater and the front right was kicking codes occaisonly, but.... no engine light!

If you can beg/borrow an OBD II scanner, you can look up the landrover specific codes on-line.

Good luck,

Roger

[gudjeon]

Has anyone tried the ethanol blend high octane trick from Husky/Mowhawk?
Every second year at twice the price- Nah, it isn't a tax, is it?

[ehmyu]

Thanks to everyone who responded. The feedback was very helpful. I learned a lot about aircare and specifically NOx this past couple of weeks. I saw a mechanic today and he tells me the cat is my culprit. I have two fixes I can go with and just want to see if anyone wouuld recommend one over the other.

1. Install the cat part only which needs to be welded on to the pipes.
approx $350

2. Install the entire Y pipe that comes with the cat. Approx $700

I am not sure if one option is better than the other but if anyone has any feedback it would be greatly appreciated.

Thanks all,
Eddy

[chilliwack]

Hey Eddy

I don't know where you are, but my local custom exhaust shop built me an exhaust from the header to the tailpipe for about $800

This included a custom built Y pipe with twin cats, center resonator, and eliminating the rear muffler and tucking the pipe up higher.

I was quoted around the $700 mark for a Y-pipe only from muffler shop.

The custom exhaust guy looked in the same catalog, said I need two cats, a muffler and so many feet of pipe. Took him less than half a day to build it.

Cheers,

Roger

[PaulC]

Hey Roger

Was the "exhaust shop" here in the Wack? Which one if you don't mind giving up your source :)

Thanks
PaulC