Catalytic Converter Failure

[dfishrmn88]

What would cause both Cat converters to fail at 20,000 mi.? Mine went out and the back pressure caused the engine to knock under acceleration. Also blew out an injector and plug. Luckily it was under warranty but wonder what could caused it. Thanks.

[kens64]

Running rich is the most common reason, as far as I know. Bad injectors and bad O2 sensors can cause the engine to run rich.

If whatever caused the first ones to go bad isnt fixed, your new ones will probably go bad too.

[dfishrmn88]

I have been running the Edge on lvl 2. Doesn't that tend to lean out the mixture? I've read threads where they were running too lean with the Edge especially with a CAI. I am stock as far as the intake goes. I have had to have injectors replaced before this happened, could this linked to the problems '05s have had with injectors? Would like to recognize a potential problem before it occurs again.

[projectSHO89]

Probably that tuner...

[dollar dee]

how do u know when the converter goes out

[Bear River]

Leaning out will overheat the cat, especially if it is lean enough to cause a misfire. The tuner is likely the cause of the failure. Most the tuners actually add more fuel, not lean them out. Tell me, is this one of those $20 chip mods that you can get on eBay? Running rich or misfires is the most common cause of failures. You should take this up with the maker of the tuner.

[kens64]

Your best bet is to get a scanner to check air/fuel mixture. Check it with the tuner on different settings. Make sure the tuner is the cause of the problem, and not something else.

[dfishrmn88]

Originally Posted by dollar dee

how do u know when the converter goes out

In my case the engine would knock under acceleration @ 3200-3400 rpm. Also mileage was dropping and always felt like the engine was working too hard.

[dfishrmn88]

Originally Posted by Bear River

Leaning out will overheat the cat, especially if it is lean enough to cause a misfire. The tuner is likely the cause of the failure. Most the tuners actually add more fuel, not lean them out. Tell me, is this one of those $20 chip mods that you can get on eBay? Running rich or misfires is the most common cause of failures. You should take this up with the maker of the tuner.

The tuner is the Edge running lvl 2, adjusting shift firmness up slightly, idle up +10, and WOT fuel at 1.40, no other changes. I don't run it with a real heavy foot but it did misfire once accelerating to enter highway.
The Edge has only been on the truck for 6000 mi.