the tube that runs from the air injection system to the first cat on my truck has rotted out where it just meets the cat. i have read that this can cause lean running, but my truck has been running fine. should i do anything about this? only problem i have is that the truck is a little louder due the to hole in the first cat. 1992 f150 w/ i6.

 

Well I am going through all this stuff on my truck right know I have a 89 5.8l. I am looking at my EGR system as well. If the hole or the tube runs into the exhaust system before the o2 sensor then fresh air can get in and give the sensor a bad reading. The check engine light well probally not come on for this. If you get the codes read it would tell you, even if the dummy light does not come on. If the truck runs lean it is up to you but it is not that great to run lean.

 

can i just let the hose run the air out and then plug up the hole in the cat? so the hose wouldnt enter the cat at all.

 

Well I am not a pro by any means. Does this tube go into the cat before or after the o2 sensor if it goes in after you may be able to get away with this if it dumps in before the o2 it should be fixed. I will check my truck tommorow and see what I can see.

 

the AIR tube feeds the converter which is after the O2 sensor. Several of the mainstream auto parts stores have a repair kit for that tube. If they don't stock it, they should be able to order it.

Plugging the converter would also work. If you have to smog check your truck make sure they can't see the modification you made.

 

i took my cats off and used a mustang delete pully in place of the pump. i get 2 mpg better fuel economy

 

A leak in the air tube at the cats won't affect engine operation but will make the exhaust noisy.

 

My '95 302 passed emissions with flying colors without that hose being connected. Mine rotted away and I didn't even notice until months after I had it tested. Your only problem may be if you get an inspector that really knows what he's doing. Around here the check stations are roughly equivalent to a government run jiffy lube.

I suppose you could be slowly killing your cat but mine never gave me any trouble and it didn't make it any quieter when I plugged the tube.