What would happen if I ran my GMC Yukon without the catalytic converter?

[Jay C.]

I got a code PO420 and PO430 Bank 1 and bank 2 catalyst efficiency below threshold. So, I was checking for exhaust leaks and heard rattling noises in my cat converter while the truck was idling. I took it to a muffler shop and was quoted for $700 to replace both converters. $200 for labor and $500 for the converters. I'm thinking of cutting the end of the converter and breaking the honeycomb with a bar and blowing out the pieces by gunning the engine then weld the converter back on to the pipe. What would happen if I ran my Yukon without the converters? Will I ruin my engine, o2 sensors, or exhaust valves? Is it okay to run it like this until I can save up some money to pay for the whole thing? I need some advice before I cut the pipe.

 

[Molson02536]

I got a code PO420 and PO430 Bank 1 and bank 2 catalyst efficiency below threshold. So, I was checking for exhaust leaks and heard rattling noises in my cat converter while the truck was idling. I took it to a muffler shop and was quoted for $700 to replace both converters. $200 for labor and $500 for the converters. I'm thinking of cutting the end of the converter and breaking the honeycomb with a bar and blowing out the pieces by gunning the engine then weld the converter back on to the pipe. What would happen if I ran my Yukon without the converters? Will I ruin my engine, o2 sensors, or exhaust valves? Is it okay to run it like this until I can save up some money to pay for the whole thing? I need some advice before I cut the pipe.

Not knowing your year of Yukon, your Catalytic converters are covered 8 yr/
130,000 km Emission Control Systems Warranty. As to running without converters will cause your engine to run on a open loop mode causing your engine to run rich. This will cause spark plugs to foul and create additional Carbon build up though out your engine, "intake and exhaust ports, EGR valve, detonations throughout the RPM range, at worst engine power reduce. It's not common for both sides to go bad the same time, so inspect your fuses and wire harness leads and try cleaning your MAF sensor and see if that helps you clear your DTC codes P0420 and P0430. You may be luck and both your O2 sensors are bad or just the wire leads.

Good luck and hope this helps and did you add any power adders to your engine that is not compliance to your ECM's program like those IAT chip that is a waste of money and effort to install it. ????