I definitely didn't DIY it but I did have to replace both catalytic converters before hitting 15k miles. I learned there's a 7-year, 70k mile federally mandated warranty on all emissions components, which the dealer forgot to mention until I brought it up.Wonder if the original poster ended up replacing catalytic converters...
I had similar scenario, replaced motor and after 100 miles or so got a P0420.
Anyone ever replace the rear catalytic converter DIY style?
The front is pretty straightforward but the rear Cat two bolts attaching to the manifold are very difficult to access.
I wish I knew! I asked the tech when they replaced it and just got a shrug.What caused the cats to go bad after so few miles?
Not so. Our vans have 2 o2 sensors per cat. The upstream one lives at the inlet of the cat, and if the sensor goes bad or the wiring to it is bad, it will read wrong and the engine will run rich, destroying the cat pretty quickly. If the engine runs rich for other reasons (bad ignition, leaky fuel injector, low compression) same story.I didn't think cats could go bad with a modern engine these days due to ECU/fuel injection ensuring properly air/fuel ratio (too much unburnt gas is hard on a cat) and gas now being unleaded (lead will destroy a cat quickly).
Interesting! I guess that is a vulnerability with the sensor system.Not so. Our vans have 2 o2 sensors per cat. The upstream one lives at the inlet of the cat, and if the sensor goes bad or the wiring to it is bad, it will read wrong and the engine will run rich, destroying the cat pretty quickly. If the engine runs rich for other reasons (bad ignition, leaky fuel injector, low compression) same story.
What are some of the other causes then? I have code P0420 and P0430. The shop I take it to tested the catalytic convertor and said there were no issues there. So before I change out the O2 sensors, what else should I be looking for? I have close to 400k miles on my van, and that's the only issue currently.The real problem with o2 sensors is misdiagnosis. Vast numbers of situations can cause too much or too little fuel to get burned, which shows up as a P0420 code. The average person reads that, goes to autozone and buys crappy cheap o2 sensors, and replaces them, and still has the code.
Not for nuthin’ but I have 3 vans, thus 12 o2 sensors. The vans have 1.5+ million miles. 11 of the o2 sensors are original equipment.