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Discussion Starter · #1 · (Edited)
Hey guys(and gals)

I have a 1991 Dakota 3.9L NONMAGNUM V6, Auto, 4x4. My question is: If I cut the catalytic converter off and gut it and put it back on empty will the truck run or will it throw codes and not run at all or run poorly. I know some cars wont even run without them on. Has anyone done this and if so what is your experience?? I know the legalities of this in the state of Virginia and blah blah blah.. Don't lecture me about the environment and toxins I will put out into the air because I do not care. Only looking for topic specific information. In the state of Virginia where I live there is not an exhaust sniffer test nor do they do anything beyond a visual inspection of the converter itself. I have already disabled the smog pump system as it failed and seized up. I blocked off the EGR hole and plugged the vacuum line that operates it. The metal line that connects to the cat converter is also plugged and sealed at the cat.

Thanks!
 

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You can remove the catalytic converter. But do not hollow it out, you will only lose power, replace it with a pipe; either welded on (best choice) or clamped on. Keep the O2 sensor in the same location, however, backspace it with a spark plug non-fouler (drill a larger hole on the thread going into the O2 bung so the O2 sensor can read something at least).

You will have a code for the EGR system no matter what (as do I after I removed it all) but it does not show up as a CEL, just retained in the ECU memory. You may have a code for the O2 sensor, but the non-fouler should help at least a little by backspacing the O2 sensor from the pipe.
 

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Discussion Starter · #3 ·
In Virginia they do a Visual inspection of the catalytic converters. I can't remove it completely. That's why I mentioned I wanted to gut it and put it back on. I thought that maybe the turbulent exhaust gas would maybe harm performance. ..wasn't for sure tho. Thanks for reply and details. Appreciate it!
 

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CaffieneTripp - he won't even have to do that.

The O2 is BEFORE the cat on our OBDI trucks.

The downstream O2s, the ones you use the non-foulers on? Are AFTER the cat, and are there to check up on the cat - so, on a single-cat (like our old stone axe and bear skin vintage trucks :rolleyes: ) no non-fouler would be needed, and could mess up the monitoring of the air/fuel mixture due to the lag the non-fouler induces (which is why it works to fake out the missing cat.)

Busseyte - what you can also do is replace the factory cat with a high flow cat (like a Magnaflow unit) and that'll drop the restriction down to below what the old cat is, avoid the power loss due to the hollowed out cat screwing up the reversion pulse, and keep you legal for inspection.

That's what I did, and they don't even inspect for cats in Louisiana! :eek:

RwP
 

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also you could hollow the cat and then run a slightly small pipe thru the cat thus making it look normal on the outside but straight pipe on the inside.
 

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also you could hollow the cat and then run a slightly small pipe thru the cat thus making it look normal on the outside but straight pipe on the inside.
Was going to say that! Just retain the shell of the converter and be done. There are some online shops that offer a fake catalytic converter; basically just the shell with a pipe through it, for an exorbitant amount of money though.

CaffieneTripp - he won't even have to do that.

The O2 is BEFORE the cat on our OBDI trucks.
Ah, never mind then. Nope, won't need to backspace anything. Haven't really looked underneath to see where the O2 sensor was.
 
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