cat plugged?
Post Fiend
Joined: Nov 2001
Posts: 14,947
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From: Topsfield, MA
cat plugged?
Drill a small hole before and after the cat. Put ur hands infront of either hole and have someone bring the RPMs up, if u feel a large difference in the pressure of the air coming out, its probably plugged. You can weld it back up, or simply make the hole large enough for a screw, and install a screw to plug up the hole.
Primary rig is Green Thunder:
95' F-150 XLT 4x4, 302, 5 spd, MSD 6A, Sunroof, CD player with 2 10" subs and some 32" BFG Muds
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Check out my Gallery for a look-see.
Then theres:
99' Mustang GT 4.6L
88' F-250 Superduty 4x4 351/c6
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Primary rig is Green Thunder:
95' F-150 XLT 4x4, 302, 5 spd, MSD 6A, Sunroof, CD player with 2 10" subs and some 32" BFG Muds
.Check out my Gallery for a look-see.
Then theres:
99' Mustang GT 4.6L
88' F-250 Superduty 4x4 351/c6
95' Mercury Cougar 4.6L V-8
80' E-350 300/6 with a
3 spd column shifter. Top speed is 65mph, Go Baby Go!
Elder User
Joined: Jan 2002
Posts: 555
Likes: 0
cat plugged?
A couple of other ideas as well.
Take her out on the highway and tromp down on her. She should pick up at a steady speed and continue but if she bogs down and does not pick up like a plugged fuel filter then a possible restricted catalytic convertor is possible.
Another way and the best is to hook up a vacuum gauge to manifold vacuum. Rev the engine up to approx. 2000-2500 rpm at a steady climb. The vacuum gauge should go steady up to 18. If it takes a steady drop down all the way to zero or close to it then a plugged exhaust is usually the culprit.
Take her out on the highway and tromp down on her. She should pick up at a steady speed and continue but if she bogs down and does not pick up like a plugged fuel filter then a possible restricted catalytic convertor is possible.
Another way and the best is to hook up a vacuum gauge to manifold vacuum. Rev the engine up to approx. 2000-2500 rpm at a steady climb. The vacuum gauge should go steady up to 18. If it takes a steady drop down all the way to zero or close to it then a plugged exhaust is usually the culprit.
Senior User
Joined: Oct 2001
Posts: 135
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cat plugged?
my '91 5.0 with about 85k had a partially plugged front cat. I wasn't sure at the time, but I went ahead and had it gutted and sure enough there was some melted gray stuff on part of the pieces that came out.But it wasn't completely stopped up. Removed the second cat also and this engine came back to life!!! I also advanced the timing about 3-4 degrees and it doesn't ping anymore unless under really heavy load or up steep hill. Also did the plugs (autolite), Bosh wires and some other stuff. Now I get up to 23 mpg under good conditions and tailgate down.....
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