99SSragtop

I'm wondering what would cause these bad numbers.
HC ppm 126 limit 55
CO% 0.56 limit 0.31
NO ppm 993 limit 408

Thanks

jimmyblue

iTrader: (11)

I'd pin it on an over-lean condition. Possibly a single
cylinder fault like crusty injector, such that the engine
as a whole is put to center by closed loop, but it's 7
fat and one lean. If you can get a scan tool to it,
look for misfire current cylinder readings on 1-8, and
see if one of them stands out.

99SSragtop

I was thinking that the engine is running fine but the cats are not doing what they are suppose to do and are failing.
They are the cats you get from SLP.

Frost

iTrader: (45)

could be, our cats nowadays maintain 3 important reactions, and they are the three items that you posted as failing.

The reactions in our coverters include two oxidizing reactions to move unburnt HC to water and carbon dioxide, and another to lower nitrogen oxides through partial conversion to nitrogen and oxygen.

99SSragtop

I have 02 sims in right now I guess if I take them off and install some rear o2's that will tell me right away if they are failing.
Well seeing as I have shorty headers at home and my stock y pipe I think Im going to switch out the slp headers and put in the shorty's @ be done with it. I don't need to replace cats every 2 years .

Frost

iTrader: (45)

no, not neccessarily