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'90 F150. - Exhaust System Question

1990 F150 , 5.0 v8, 4x4 , longbox.

Bought it recently for $500. Truck has 170k miles, "Rebuilt Engine has 65k. Rusty, but runs strong and starts immediately and doesn't burn oil. No regrets. But its LOUD.

Removed the {completely empty} glass pack and put on a real muffler. Still loud. Found the problem. Appears there are two catalytic converters, basically inline. The short pipe between the two has a fitting on it that vents exhaust gas and noise straight up into the engine compartment.

God Bless the chilton book I have that completely omits the exhaust system. (I'll save that for a different rant/thread)

Questions: Where's that hole supposed to go? Can I cap it off? If I can cap it, with what?

NOTE: I don't expect many years of service from this truck. The rust is non trivial.

Thanks , Mike D

Reply to
mpdsville1
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Sounds like it would be an O2 sensor bung. Why it would be in between two cats is beyond me. Usually there is one before a cat and one after the cat to make sure it is doing it's job but then I have never seen two cats in series before. Sounds like more "barnyard" mechanic work to me.

Razor

Reply to
Razorblade

That is the air tube from the air injection pump that is supposed to be mounted to the lower right front of the engine. It is to provide fresh air to the converter to complete the combustion process. If you do not have to deal with emissions inspection and someone has removed the injection pump, you can put a cap on it. A muffler shop should be able to do the job.

Lugnut

Reply to
lugnut

An honest muffler shop will not be tampering with his emissions system. He could easily plug it himself with a tapped screw or a lag bolt.

Reply to
Al Bundy

Thanks again lugnut. The pipe to the airpump is gone, just a rusty stump left on the exhaust pipe side. I'll cap it off as I'd rather not shake/bend the exhaust/cat assembly too much (and wind up with new cracks), and judging by the rusty stump it will take a lot of force to get the old fitting off. The hole is appx 3/4" ID. Any creative ideas how to plug it?

Reply to
mpdsville1

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