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need help removing front catalytic converter on 91 F150

 
  #1  
Old 08-06-2002, 01:57 AM
jwchatm
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need help removing front catalytic converter on 91 F150

I have a 91 F150 with 5.8L EFI V8. It has been overheating. We replaced the Clutch fan, radiator, radiator cap, temperature cooling sensor, and thermostat and still it overheats. I am also not getting much power and only about 7 mpg on fuel. This sounds like the problem you resolved by changing the cat. Here is my problem. My 91 F150 came with 2 Cats. (I assume that this is what they referr to as "California Emmisions". We think that the front cat is blocked and would like to remove it leaving just the 2nd cat which is all I need to pass emmissions here in Colorado. My setup looks like this. I have an exhaust pipe coming off of each exhaust manifold that bends to run parrallel to each other. They both enter into the front cat instead of joining together and then entering as one pipe. Then there is one pipe going from the front cat to the rear cat and then on to the muffler ...etc...etc...etc. Where the two exhaust pipes from the manifolds enter into the front cat...there are no beads of weld or bolts or other fasteners present. The pipes look as though they simply slide into the cat. Can I drop the exhaust system and tap on the cat with a hammer or other tool and get it to slide off of the pipes or are they welded in from the inside or crimped on or something like that? I was thinking if I can get the cat off I could use an adapter to join the two pipes from the manifolds into one and rejoin that pipe with the 2nd cat to complete my exhaust system. I do not want to beat on the front cat if it will not come off. I thought about cutting the pipes just in front of the cat but there is a slight bend that will make it difficult if not impossible to clamp onto them and get a good seal. Unfortunately I do not have access to a welder to weld them or I would. Please tell me how you removed your cat and whether or not those manifold pipes will slide out of the front cat with a little coaxing from a hammer. Thanks for your Help!!!!!! Please email me with the answer at jwchatm(No Email Addresses In Posts!) or [email protected]

John Chatman


:-X11
 
  #2  
Old 08-06-2002, 02:46 AM
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need help removing front catalytic converter on 91 F150

That two cat setup isn't just cali emissions, it's for everyone.


Primary rig is Green Thunder:
95' F-150 XLT 4x4, 302, 5 spd, MSD 6A, Flowmaster American Thunder Exhaust, Sunroof, Clear corners w/ Diamond headlights, 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 Heavyduty 4x4 351/c6
95' Mercury Cougar 4.6L V-8
80' E-350 300/6 with a
3 spd column shifter. Weighs around 7,000lbs w. 65mph top speed, who wants to race me!

 
  #3  
Old 08-07-2002, 01:01 AM
pross
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Post need help removing front catalytic converter on 91 F150

I just took my '91 5.0 to a muff shop and had them cut the pipe coming out of the first cat, and he hammered the old ceramic stuff with a long punch. (to break it up) Then cranked up the motor to blow out the loose pieces. Then repeated this about 3 times, and starting the motor ea. time to blow out the pieces. And sure enough there was some melted gray stuff ?? that came out. Then he welded the pipe back in its place. My second cat was good- you could see thru it. But I had t removed anyway. This brought life back into my ride!! It will have an echoing, hollow sound. Same as I did on an old '78 Granada. You could hear the diff. But, no, you can't disconnect the cat without cutting and welding....(or taking off at the exh. manifolds which I don't think you want to do that).......
 
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Old 08-07-2002, 01:03 AM
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Post need help removing front catalytic converter on 91 F150

I forgot to mention-partially clogged cat WILL cause overheating and loss of power.
 
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Old 08-09-2002, 10:22 AM
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need help removing front catalytic converter on 91 F150

John,

If you're in the Denver area, call around to some of the shops. I've had good luck with Bud's Muffler. Here's what I had them do to my 91 with the 302. I had the same "cat into cat" setup from the factory. They knocked the stuffing out of the front cat, cut off the second cat and installed a single 3" high flow cat then 3" pipe. You can then finish the pipes however you like. I haven't had to have it inspected yet, but it should pass fine. With this setup the highest I've ever seen my temp gauge go is almost to the "O" in NORMAL and that was pulling a 6500# trailer last week, with AC and 95 degrees! The gauge used to stay between "R" and "M" just driving around!


Spudco

 
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Old 08-10-2002, 12:36 AM
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Post need help removing front catalytic converter on 91 F150

just curious- how much did the hi flow cat cost, and did you have to special order it? Did you leave the air flow tube as is on the front cat? thanks........
 
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Old 08-10-2002, 05:08 AM
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need help removing front catalytic converter on 91 F150

 
 
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