Exhaust gas coming from the air pump

[paulg]

Just recently I redid the exhaust on my 1994 Ford F150 I6. I installed CP dual outlet headers and piped them to 2-2.25" pipes into a 3" pipe, 3"in/out catalytic conv and into a 2.5" in/out Flowmaster 40 series muffler. On the backside of the air pump(side that faces toward the firewall) is a 1/2" hole thru which you can see a spindle and the impeller for the air pump. It is thru this hole the exhaust gases are coming thru. I am concerned as I never had this problem before and now I smell exhaust when I turn on the AC or heater. I am sure this shouldn't be happening. Could this be caused from to much backpressure in the exhaust? Any ideas?

[rlbertrand]

[walterdanek]

That is supposed to attach to your exhaust manifold, right before the catalyic convertor. Might be hard to see, but it's tucked up there on the top. You will see a "pre-cat" chamber. The air pump hooks to the upper back of that (If it's the same from my '84'). If the tube is missing, then that is where your exhaust fumes are coming from. I'm told that is supposed to add air to the exhaust fumes to allow the cat to burn more stuff off. IL6's are to have a bad breathing problem, & need lots of air. Guess this was Ford's easiest fix.

Good Luck
Walter