Can removal of emission equipment causes the engine to make a knocking or misfiring sound ? It's a '83 F250 with the 460, I had removed the air pump and most of the vacuum lines.

Bert

 

i dont see how unless your hearing spark knock. under what conditions do you here it? hows your oil pressure? i would check the timing and make sure you have no vacuum leaks then see if it still does it.

 

Sure it could! The emissions equipment was actually engineered to work with the engine and together. For example, engines that used the A.I.R. pump were typically jetted to run on the rich side so there would be enough unburned hydrocarbons left in the exhaust that the injection of fresh oxygen would cause them to burn completely. All you really gain by removing the A.I.R. pump is the reduction of drag from driving the pump itself. To properly remove it, you need to plug all the ports in the exhaust manifold where the injectors were and if it's carbuerated, lean it out a bit. Make sure all of your vacuum hoses and lines are plugged off and that there are no vacuum leaks. The same applies to other emissions equipment as well. Also, double check your spark plug wiring and make sure you didn't switch a few by mistake....that will REALLY make it run bad!