3.0L Exhaust

[RossOtero]

I wanna ditch my cat and have just a performance muffler tacked onto the tail end. The truck was dumping smoke and has since been rebuilt. The goals are to get the truck breathing efficiently (since chances are the cat is clogged) and sounding mean with a low rumble. What all have you guys done?

[Law Dog]

Sounds like you might need “test tube” to see if that cat is plugged don’t forget to remove it after the test. LOL

[xboxrox]

My (all original cats) California emissions truck nearly 10 years older than your 94 Ross had two cats but now has only one ~ we removed the front cat coz it was totally plugged crystalized like solid stone ~ no replacements are available & the only way exhaust passed thru was that canister style cat was surrounded by a 1/4" thick metal mesh screen (see my cat cyl head thread photos) Well anyway IMHO I think an engine can run better on an ECM if it gets accurate data from O2 sensors ~ so if the ECM is tuning your engine THEN I if me would inspect test repair replace as needed the cat & O2 sensor/s

We are so blessed to own our little truck ~ although maintenance $ has cost a good penny ~ it is finally running pretty decent, not burning oil and gets 20.5+ MPG with off road AT tires ~ it's paid off too ~ we need it for medical appointments in Honolulu & grocery runs to the MCBH 4 miles from our apt ~ God Bless America

And Best Wishes to you too Ross

[RossOtero]

Thanks xboxrox and lawdog! I live in rural New Mexico so I have no emissions laws to worry about that being said, do I have to have a cat in order for the v6 to run efficiently? If removed, would I need to tune the truck to avoid check engine lights? And is the back pressure necessary for the truck to run well? Thank guys for all the knowledge. I agree xboxrox our trucks are gems that get noticed every time and make heads turn! Always getting the “is that a mighty max?!” At the local gas stations

[xboxrox]

Hi Ross,
Good questions but a more knowledgable member would have the answers, I don't... I don't even know if my truck has a check eng light (a red EGR light comes on with the oil pressure seat belt lights with ignition ON and after starting all the lights go out...) I don't even know if my truck is OBD1 or if it even has a harness test plug connection..? I think not..? It is my best guess that removing the cat would not set off a check eng light BUT without modifying the ECM removing O2 sensors would probably set off the light..? Those are good questions and several folks here will be able to give you a straight & correct answer... Google says removing the cat will not (99% of the time) increase your engine HP and torque...

How COOL folks like your truck

[Chargerx3]

94 was a transition year for Mitsubishi, so you might want to verify that there isnt a downstream (after the cat) o2 sensor. The years prior didnt.

I personally think the 3.0 SOHC doesn't sound good opened up. Nobody will be impressed and you will increase cabin drone. If you want a quick way to see if you like it, you could aways fab up a test tube and see if that makes you happy.