F250 Catalytic Failure

TexBohunk wrote:
Truck is all stock except a magnaflow muffler. Check engine light was on. Code pulled was P0420, Bank 1 out of range. Bank 1 is the passenger side of engine. The 2nd O2 sensor measures the efficency of the cats. According to 10m05 the cat would get too hot inside and melt or crack, then come apart. The repair replaces the entire Y assembly with an improved part and a PCM retune. Was impressed i got 7.5 mpg pulling over 7000lbs with a head wind, rolling hills, and a restricted exhaust at 55mph. LOL!

Did you replace the upstream O2 sensors?

Good chance bank one sensor is BAD and if it is bad it will signal the PCM that the bank is to rich and the PCM will add MORE fuel creating an over rich mixture which then poisons and FRIES the cat..

O2 sensors ARE a "wear" item.. older ones (no heater) were only rated 50K miles.. Newer ones with heaters are rated 80K miles.. after 80K you are living on borrowed time..

My 08 V10 had both replaced before I bought it. Just EPA******killing the engine.

Truck is all stock except a magnaflow muffler. Check engine light was on. Code pulled was P0420, Bank 1 out of range. Bank 1 is the passenger side of engine. The 2nd O2 sensor measures the efficency of the cats. According to 10m05 the cat would get too hot inside and melt or crack, then come apart. The repair replaces the entire Y assembly with an improved part and a PCM retune. Was impressed i got 7.5 mpg pulling over 7000lbs with a head wind, rolling hills, and a restricted exhaust at 55mph. LOL!

Not an F250, but my 97 F150 5.4 had a cat fail on the drivers side...there's four on the 97, an upper and a lower on each side...the upper failed, came apart, and completly plugged up the lower cat. Blew the DPEF sensor hoses off the sensor there was so much pressure. Had 150k miles on the truck...no warrenty for me.

Had to cut a relief cut in the exhaust to get the truck to a shop.

Anyway, the truck was worth 3k and I wasnt about to spend 1k on a Motocraft catalyst.... Went to Napa and they installed one large Cat in place of the two smaller ones, they also replaced the O2 sensor and I went along my Merry way.

No CEL's or any problems from the Napa Cat.

I don't think that 5.4's fail at an alarming rate, mine had 150k miles on them. I think my root cause was a fouled plug on the drivers side bank and raw fuel being dumped on the cat, but I'm not 100% sure.

Glad you have got it fixed though!

Thanks!

Jeremiah

Good info. Thanks for posting and glad they fixed it for you.

Had a 08 F150 that burned up a cat around 60kmi. Got so hot it cooked everything on the right side of the engine that was not made of metal. Figured it was a freak occurance. Never heard of another case until now.

Tuner?

I haven't heard of the 5.4 killing cats. The EB, yes.

Any codes or CEL's? To kill a cat they usually misfire and fill the cat with raw gas and then it will cook them.