failed smog FTL!

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eg6sir

Supa Mod
VIP
went to smog the pickup today.. bam, failed.. wtf?!? passed w/ flying colors 2 yrs ago w/ very low numbers... still had very low numbers except one test

15mph HC: max 133, meas 12... CO: max .59, meas .01... NO: max 1050, meas 1224

25mph HC: max 113, meas 13... CO: max .74, meas .01...NO: max 910, meas 80

whats causing me to read so high on the 15mph and read so low at 25mph on the NO test?
 
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What is this "smog test"? Is that something over in thar yonder commiefornia?
 
wrong gear used for the test would be my only guess
kept the truck in 1st and spun it to 15mph revving the motor too high
 
so the test requires a specific gear?
perhaps the motor was spinning too slowly and loading up resulting in excess gas in the exhaust
seems it would have a direct relation to engine rpm to have such a huge difference between the 2 speed tests
 
If I'm not mistaken, isn't nitrogen oxide what the catalytic converter converts? I know the platinum catalyst in the presence of an alkene leads to hydrogenation of that alkene, but I'm unsure of the effects on inorganic species... Just a thought.
 
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Is the cat one of those 2 year cats that were going around? What I mean is.....did you buy a new cat for the last smog and now its not cutting the mustard?
 
What was your o2 @ on the 15mph run? NOx is usually the indicator of running lean. So if your o2 is kinda high, look into things that would cause "too much air" to be entering the engine. If your o2 is still somewhat normal, look into things that would cause "not enough fuel" to be entering the engine.

I'm sure you know what lean and rich are lol, but you'll be surprised at how many people don't realize that not enough fuel could be lean and not enough air could be rich as opposed to people seeing rich and going straight for fuel and seeing lean and going straight for air...
 
What was your o2 @ on the 15mph run? NOx is usually the indicator of running lean. So if your o2 is kinda high, look into things that would cause "too much air" to be entering the engine. If your o2 is still somewhat normal, look into things that would cause "not enough fuel" to be entering the engine.

I'm sure you know what lean and rich are lol, but you'll be surprised at how many people don't realize that not enough fuel could be lean and not enough air could be rich as opposed to people seeing rich and going straight for fuel and seeing lean and going straight for air...

it measured 3.06 @ 15mph


i'll be sending in an application for CAP, CAs repair assistance program.. $500 towards repairs
 
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