In theory that works, butthey fail, I remember one truck inparticular a 93 Ford 5.0L had 3 cats inline and failed. I think the flow of the exhaust has "bursts" and when you get a burst of exhaust right on the sensor, it knows somethings up and fails it.

 

I do wonder if multiple cats inline would help, someone should bite the financial bullet and try it!

 

No multiple cats wont work unless you feed air into them somewhere, i.e. cats with AIR tubes. The O2 will burn up in the cats trying to burn up the excess fuel. With out O2, your exces fuel will not burn. What i plan on doing is using the stock air pump i removed, running a tube to a fitting right before the car and forcing air into the exhaust which will not only burn up the excess fuel, but it will also dilute the exhaust.

 

i heard that our AIR pump only turns on at start up. If u hardwired it to run all the time wouldn't that do just what ur talking about pushing more air into the exaust w/o the problem of running suspicious tubes down into the exaust pipes?

 

I agree with Injuneer. The extra air that was in the exhaust would make the pcm think it was lean, and add fuel. It would probably fail worse like that.

As for removing spark plugs too, it is still going to see extra air in the exhaust. Not all of the air would escape through the plug hole.

If you had tuner cat, you could make it run super lean, but then doesn't that raise some other level in emissions like nitrogen oxide?

 

Yeah it only turns on on start up. I have mine out of the car. I deleted AIR and EGR so i was gonna use the AIR pump if i ever got my LE2 package and run it right before the cat. The guys in the inspection lane wouldnt know much about it. Most cats have an air tube they draw air into. Hooking a line up to it wouldnt arose to much suspension i dont think. It WOULD work 100%. It's worth the possibility of them finding it and taking it off. I would just hardwire the stock AIR pump though to run all of the time. It would do the same thing and they would be non the wiser.

 

wait doesn't the AIR pump pump air into the exaust allready why would u need to run a line down to the cat? couldn't u just leave it on in the stock location and hard wire it to run all the time?

just thinking out loud

 

will a colder plug cause problems with smog? autolite 104s gapped @ 40

 

Same problem I mentioned in the earlier post. Pumping the excess air into the exhaust manifolds full time would show up at excess air at the O2 sensors = "lean" = PCM pouring extra fuel into the cylinders to cure a condition it can't cure.

For the "AIR pump" concept to work at all, you would have to inject the air after the pre-cat O2 sensors. If you have an OBD-II car, then the after-cat O2 sensors would pickup the deviation between the pre-cat and after-cat sensors and set a code.

 

do u think it would work or is there a better way?

 

My approach would be to fix things so the car runs correctly, and passes. Why jury-rig it and cover up a problem. My 500HP stroker passed NJ rolling emissions with the cats in place. And that's on a system running open loop.