Need a little help passing my inspection

[BigTruckDriver]

The NOx(PPM) levels are too high.Everything else was fine.The guy says I might need a cat. converter.I told him this one is about 3 years old,how long shoud one last?I also told him I do not drive the vehicle much,I am out of town most of the time.Drove it maybe 100 miles in the last month.He said run it on the highway and bring it back.I did also have the cheapest gas in it also.Is there any fuel additives that I can use to also help bring the leveld down?Thanks for any help http://www.gop2.com/pi_improver_gas_additive.html

[cffisher]

Don't know about TX but in Il. when we didn't pass with our (other than stock)cars we'd just leaned them out and take them back worked every time.

[BigTruckDriver]

I guess I also could of let the vehicle fully warm up also.

[Aster]

BTD, I would think that converter should last longer than that unless your running real rich.

[robot]

Dont buy a new converter!!

Read this article for explanation:

http://www.thirdgen.org/newdesign/ar...missions.shtml

If you can't tune it out, take it to someone who has a sniffer....they can
adjust it usually....and it is really cheap (usually).

[Itoldyouso]

I've seen additives in parts stores that "guarantee" you will pass the emission tests. Never had to deal with this, so can't vouch, but maybe worth a try.


Don

[Big Tracks]

I don't have anything that needs it at this time, but I've used that "RXP" stuff and I really believe it works. I have bought it at O'Reilly (sp?) and Quik Kar in the past. It comes in a little dinky bottle about the size of those little bottles of liquor you used to pay too much for on airplanes. It cost several dollars a few years back. I don't know how much they'll soak you now.

Jim

[BigTruckDriver]

BTD, I would think that converter should last longer than that unless your running real rich.

The other thing that could possibly be affecting my converter,and truck is that I dont drive my truck much.I travel for my work,so am not at home much and the truck sits. I have my wife turn it on once in awhile. In the past month I have drove it maybe 70 miles MAYBE. Would this affect the converter?I did try one of the additives ,and drove the truck for about a hour ,but still failed the numbers were down a bit but still to high.The additive I used was the RXP stuff,I think it works.

[HWORRELL]

The 3 things that will raise Nox are, 1,an overheating engine, 2, an EGR system that is not working, 3, a dead Cat....I can tell ya from experiance that the egr system is the biggest culprit but with that being said the second biggest culprit are those cheapy aftermarket cats most will only get you by for 2 to 3 years...Also advanced ignition timing will raise Nox

[Aster]

BTD, you need to have it checked. Sounds like something is wrong and you don't want to mess around with cc's. Good luck.

[BigTruckDriver]

The cat is one of those cheapy ones from auto zone.I am going to replace with another and change the oil,plugs,rotor,cap,and wires.The motor has about 200 thousand miles,maybe I will just do a rebuild and go from there.I thought the motor was doing pretty good though ,just a little puff of smoke at start up,but drives GOOD ,and gas mileage is fine. Anyone have a link for a good compression tester.I need a good quality one.I think I need to check the compression before I go any further.

[RAYJAY]

OK I'm new here but if your running a cat on the car /truck (more info on what your running would help ) do you have o2 sensors on the motor also ?

if you do and there over 75,000 miles they will cause a load of problems

jeff

[BigTruckDriver]

89 chevy suburban fuel inj.350

[robot]

If you live in the San Diego area, there should be thousands of garages who have emissions testing equipment....Pep Boys may be one of them...you gotta ask.....usually, the independent garages are more apt to be trained on the equipment. We just had one done here...it would not pass and the guy was doing a remove and replace to find the problem.....we forced him to go to a garage and they charged him $30 bucks and fixed it on the spot.

R&R is not a good way to fix the thing....too expensive.

[HWORRELL]

OK I'm new here but if your running a cat on the car /truck (more info on what your running would help ) do you have o2 sensors on the motor also ?

if you do and there over 75,000 miles they will cause a load of problems

jeff

He is failing on NOx, 02 sensors will not cause a NOx failure,unless it's very very lean but if it was it would usually cause an HC failure also. 4 things will cause a NOx failure,
"in order of most common"
1....EGR system
2.... Catalytic converter.. usually will fail NOx along with HC.
3...Advanced ignition timing..
4.... overheating engine...