Catalyst Converter Problem....

[HUMTECH]

Originally Posted by IRA51

a P0420 is bank 1 I think and it could be anything from an exaust leak to a bad cat . some times a bad O2 can set it . if the down stream O2 does not see much of a reduction it can set it . I would check the O2's first to see if they are good B4 changing the cat .check your coolant level,a leaking head gasket can kill cat's and O2's .

Correct, p0420 is bank 1 catalyst low efficiency. Outside chance that an o2 sensor will set this code, but is possible. Also needs a pretty good exhaust leak, at least one audibly noticable to set it. But still possible for sure. As said above, check for exhaust leak, o2 scan data would help, but in the end my money would be the cat is bad. In my experience i have never seen a low catalyst efficiency code set that a new converter didnt fix. I even gambled on a couple that had headers installed that were leaking badly and turned out the new cats fixed them.

[HumminNBoatin']

Mine had both cats replaced in the 50k to 60k Range One went bad and then one after that shortly followed. Also I think the warranty on Cats is Over 8 years and I am not sure of the mileage. Humtech may know the answer to this.

Eric

[HUMTECH]

I believe they are covered for 8 yrs 80,000 miles. Not positive though

[Rene S. Nielsen]

I just cut a hole from top to buttom in the middel of the cat and then straight across in both top and buttom.

Then I open it up with some pliers and pulled everything out. pused "the flap" back and welded them up.

And yes the check engine light will light up all the time.

I'm looking into getting some new cat's but everything for the Hummer is pricy in Europe and takes about 14 - 20 days to get every part.

Rene

[IRA51]

if you can weld and have a Mig ,high flow universal cat's are under $110.00 each at retail. I like the Magnaflo cat's .