Well i was under the truck today and noticed that there was pipe hanging from under nieth to where the exaust sits ' i had a new exaust put on some time ago and think they might have left somthing alone here.

This is where the hose starts up top then goes down to the exaust area.



Same hose that is runnig along the intake l .



This is where it sits just hanging there.



Should there be a plug in there or what should i do ' just leave it ' i think this would be considered a vacume leak' correct me if im wrong but i need some more knowledge on this piece as iv been avoiding it for some time now.

The truck is a 4.9 il6.

 

That's the line for the Secondary Air Injection system. The loose end of the hose is supposed to connect to the air injection tube on the catalytic convertor. Without it connected, the convertor will not function properly and may clog since it lacks the air necessary to burn the contaminants. You need to reconnect it and have your cat tested for backpressure ASAP.

 

Thanks strangeRanger but i have no cats under there ' what should i do?

 

Buy an aftermarket high flow 3-way cat and install it then hook the hose up to the air injection tube on the cat.

There is no excuse whatsoever for not running a cat. The current ones cost something on the order of 2-3 HP vs. straight pipes. It's just plain ignorant to cut them off and crud up the air that the rest of us have to breathe.

 

I think ill go to the junkyard and cut 1 off a truck there ' it might be cheaper for me as i dont have alot of $$.

Btw would a open hose like that cause poor gas milage.

 

For the cost difference between a fresh cat and a junkyard one, I wouldn't take the chance on getting one that is damaged or clogged (which will cost you power and mileage). Check Summit's prices on Catco and Magnaflow high-flow converters. You might be surprised.

The open hose affects nothing except the operation of the cat. It simply directs air from the smog pump to the cat. It is not connected to the engine in any other way.

 

just clear the cat out if u live somewhere with no emissions like me. youll get like6 more horsepower and more mileage.

 

So Big Red, do you still breathe air? The rest of us do and at least some of us prefer that it be clean. Modern converters are very efficient. They cost zero on mileage as long as it's not clogged and reduce RWHP by only about 2-3. Why do people insist on removing them? It makes absolutely no sense.

 

Agreed. There is no sense in removing properly working smog equipment. I dont know why everyone insists on it so much. There is NO gain from removing the pump itself, and almost none from removing a cat.

 

If you want low restriction and noise, use a high flow cat and a straight pipe.