Hi all - first post here. Hoping you guys can help me out.
have a 2002 mazda b3000. 3.0 V6 Base. Manual transmission 4x4. Have a strong feeling I have a bad/clogged cat(s). Been getting codes for throttle position sensor and ICV but they’ve both been replaced, throttle body cleaned, new MAF. I think it’s the front cats but they’re hard to find and expensive af. Want to hollow them out but wondering how it’ll affect the O2 sensors. Will I need a delete? Will they still work? ANY ADVICE is appreciated. I’m a backyard mechanic and just enjoy working on things myself. Thank you.

 

Welcome to the forum

If the engine is starting to take throttle idling normal, does not get reduced MPG, no rotten egg smell for the exhaust then it is not likely the CAT is your issue.

You may keep in mind that in all states that I am aware of it is illegal to gut or remove a CAT (check your state laws but remember Federal law overrule state law) offence and in some states your vehicle can be impounded on the spot. Also if you enter any Federal reservation (like a federal Park) it could be a felony should any mishap during your travel in them with a modified or removed CAT?

Removing CAT or temporarily using a "TEST PIPE" may need to consider the ECU regarding engine operations? You might get lucky and only need to use a O2 riser? There are a couple of B series with a little mor experience perhaps to answer this a little better?

 

Hey thanks for the reply. I do know it’s illegal and would prefer not to gut or remove the cats. I just think it has to be the cats. They get super hot, very poor acceleration and mpg but no rotten egg smell. I suppose I’d just really rather not drop the money as the front ones are the issue and they’re not cheap.

 

A CAT will run between 500 to well in the 1000F degrees depending on various influences like, IATs, RPM, load, etc. So unless you measured the EGT or the CAT F from access the ECU and CAT temperature how do you know its running hot? Sometimes but not always you engine coolant may running hotter then normal. But you would also need to check this with a independent gauge or a scanner if you can access the actual coolant temperature and not what the dash needle is indicating by position. .

You should have also got at least 1 or more DTCs because a failing or failed CAT will cause other sensor problem that will report to the ECU. So look for DTC in pending area of the ECU.

If you had access to getting the tail pipe exhaust reading this would also tell you if the CAT failed.