What to do about my catalytic converter | Ford Explorer Forums - Serious Explorations

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What to do about my catalytic converter

NudieWin

Member
Joined
October 15, 2007
Messages
48
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City, State
Minnesota
Year, Model & Trim Level
'97 Explorer
I just got a new flowmaster exhaust put on yesterday and they told me my cat assembly is on its way out :thumbdwn: and they could do it for 600 dollars or so I was wondering if anybody had any suggestions....

*cough*legal or not *cough*...

A buddy of mine is a mechanic and said he can hallow it out for me as it is getting plugged up. I was wondering with that once its hallowed out is my check engine light going to continue to stay on or will it go off after that?

Also I was wondering how hard of a job it is to do?

Maybe I could tackle it myself?

The guy at exhaust pros said if I just let it go it can eventually blow my motor up, since im new to all of this I dunno thats why Im glad I got all of you :D

Edit: 1997, 4.0 explorer if this matters?
 



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just replace it.... $600 is a rip off, now way in hell does it cost that much to replace....

it is illegal to remove it if it is still good, but if your cat is bad, then replacing it is not illegal

hallowing out is also illegal, and it may trip a downstream o2 sensor
 






$600 is too high.. I had a new high flow cat installed (flowmaster brand I think), about 8" farther back from stock and it cost me < $400 out the door.

~Mark
 






Is it something I would dare do on my own? He told me it was cheapest it could get done around here, but the same guy I know that would hallow mine out right now for me builds race cars so maybe I should check with him first.
 






your right im finding catalytic converters for 62 dollars for a universal that will fit...not that thats out of the way does anybody recommend a certain catalytic converter that is better than the rest?

If there is one for performance maybe?
 






which one is plugging up? I cut off the back one on mine and left the front one and it runs fine. Just get rid of one.
 






not sure he said my check engine light is on and as it stands now its not so Im gonna have my mechanic run through it quick and see who credible it was. Might still get a new cat just for giggles though.
 






run a vacuum test on the engine, it will show whether your exhaust is plugged up. Then go from there.

If you do replace the CAT, look at the hiflow aftermarket ones they are much much cheaper than the OEM replacement and they flow better. I think they are like 60 bucks :thumbsup:
 






run a vacuum test on the engine, it will show whether your exhaust is plugged up. Then go from there.

Huh? Please explain this test.

The first question I would ask the mechanic who diagnosed a bad cat is 'How can you know?' A check engine light accompanied by a code that shows a catalyst inefficiency is not the same thing as a bad catalytic converter. The two do not necessarily go hand-in-hand.
 






When you test you vacuum at idle it should be within the normal range say 19hg to 22hg, then rev the engine to 3000 rpms and hold it there, the vacuum should initially go down when you hit the throttle but then settle to about the same as the idle number. If at 3000 rpm the vacuum is much less then the "normal" range then chances are you have a plugged up exhaust causing high backpressure. If the numbers are much higher then normal ranges you have an intake flow problem. This all hinges on the fact that the engine is within normal ranges at idle.

One note though is if you have a non OEM cam they can have adverse effects on vacuum if you have a higher duration grind.
 






If I were you I would just replace it with a straight piece of piping. As for the check engine light it can be fooled… plus you will have a notable difference in pep.

I did this to a 96 ranger. A while back and it ran fine. Only noticeable difference was a slight exhaust smell. Like an old muscle car smells.

To fool the check engine light you just have to replace the second O2 sensor, the one after the cat, with a resistor of appropriate resistance to trick the computer into thinking that everything is running smoothly. This works because as the amount of oxygen changes in the exhaust system the resistance across the O2 sensor changes accordingly. I don’t remember the resistance I used on mine but I found the correct resistance by using a mutly meter to read the resistance on a different ranger with cat intact and no check engine lights on.

So in the end I was down to just one o2 sensor and no catalytic converter and a littler more power.

Remember this is only if I were you…. ;)
 






i removed my y-pipe from my 01 sport and hallowed it out..and rewelded the opening back on..its been like 3k miles..and no engine light and the truck runs better IMO..BTW i also don't have a muffler so basically its running a straight pipe
 






I have seen people weld a O2 sensor fitting onto a straight pipe.
 






If I were you I would just replace it with a straight piece of piping. As for the check engine light it can be fooled… plus you will have a notable difference in pep.

There are some states that actually perform emissions testing, getting caught without cats will cost your an arm and a leg if your caught.
 






That is true Manaen… good point
Fortunately I live in KY and we don’t have emissions testing.
So you DO NOT want to use this trick in a state that requires emissions testing.
 






I'd like to remove my rear cats but Missouri has a visual mechanical/safety inspection so it would fail on that alone.
 






I have a 5.0 a whacked the back two off, no need for them (no emisions either) you can get $ for your old cats at a recycling center btw.
 












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