Racinrhino17

Sometimes I think they do a "puff test". Do the two downstream only

DrillRig52

They should only do an OBDII test on your truck. 95 model year and older get the "sniff test" and that is when they put a sensor in your exhaust and check for a certain amount of hydrocarbons " unburned fuel" at an idle test and high speed which is just revving to 2200 rpm.

You will pass under these two circumstances.
1. Your vehicle does not have a code thrown "check engine light"
2. The inspector does not get under the truck and physically look for cats.
Those are the only two things you need to worry about in most states with an OBDII vehicle. And 95% of the time an inspector is not going to get under your truck.

My03fx4

They really work, I've been running my truck with the non foulers for almost a year new and I have no codes for the sensors or for not having cats.

me1234

Unplug battery for a while then plug it back in. The light stays off for a while at least. Not sure about the codes though

kirklandkie

Codes won't be there if you do the battery trick. But sometimes they'll plug the computer in and tell you you have to drive around (100 miles or so) before they can test you because there is some sort of data collecting period with the computers. Thus, a code will reappear if you simply disconnect and reconnect the battery

-Kirk

DrillRig52

Yep, don't do the battery thing. Could cost you a failed emissions test.

gkos_

What if I delete the codes with my diagnosis tool then get the test real fast would I pass?

ruler242002

I've been running only the down stream cats for about two years now. Never had an issue with inspections and never thrown a code.

windsors03cobra

It will reset any set monitors and you will have to drive around 50 or a hundred miles to reset monitors. Once a monitor fails its test the check engine light ruins any chance you might have had.

No sniff tests here, only OBD2 cars are tested. Something about wheel dynos and 5 gas analyzers being very expensive to maintain and not as many cars out there.
A new car shouldnt need a test foratleast 5 years from manufactuer, what a crock.

fordfan66

Are there any codes that will show up if your CAT is either burnt out from too many misfires or worse fallen apart and not even there?

MIL or Cat Eliminator could work in this situation.