Rick Brandt

Alright here is my issue. I have been having issues with my cats for 2 years now. I bought the Jeep with bad cats and the dealer where the unit was bought replaced them at no cost to me. All was well for six months when the cats failed again. Not sure why. Two weeks ago the Jeep reduced power and would hardly go also the manifold and cats were getting red hot. I was getting the P0420, P0430 and P0300 codes. This week I have replaced the complete Y pipe and cats, all new O2 sensors, air filter, plugs and wires and pcv valve and driver side manifold. All codes were cleared and adaptive learn reset. The vehicle runs great, has more power than ever, almost like new it has not ran this well since I bought it. The problem is that the manifolds and cats are still getting red hot. I have put over 300 miles on the vehicle and no codes come up and still runs great the dealers won't even look at it unless it has codes and the auto shops that I have gone to will connect it to their diagnostic equipment and all shows good. I need to get this figured out before new cats are toast. Not sure where to go from here. Btw the Jeep has 190,000 miles.

ChadHubbard

I don't know if this is helpful, but maybe something to think about. Raw fuel entering the cat will make it run hot. I am not sure about oil. At 190xxx miles are you burning a LOT of oil? Is compression so low on one or more cylinders as to create bad combustion? Is it possible you have a cylinder overfueling or a cylinder not firing? I saw that you replaced the plugs and wires, so maybe no a misfire.

I don't know what other than fuel will make a cat run hot.

Good luck! Pls let us know what corrects the issue.

Mark Doiron

If diagnostics aren't reporting your cats as hot, they are probably at normal temps. Mine run anywhere from 1350-1800° when driving normally. That's pretty hot. You might actually measure the temps on yours and see what they are. If you have an Android device, then Torque Pro and an inexpensive (less than $10) OBD-Bluetooth adapter may give you some better info on how your Jeep is running.

Rick Brandt

Thank you guys for the replies. I ran live data from my Bosch scanner and got a high of 1760 and a low of 1300 on my cats at 60 mph. Still getting no codes and also ran an emissions test for the fun of it and it passed. Not really sure what the deal is. I do my oil changes at 5k and am only low a quart every time. I would think if it were a compression issue the engine would not run as well as it does. But who knows. I'm just afraid that I'm gonna burn the Jeep down if this keeps up.

Trail Jeeps

I had a supercharged 07 in my charge that would glow after heavy trail use.

They do tend to run hot, but if they're usually so it can have to do with fueling and oil burning.

As a previous poster said, do you burn oil? Do you have any aftermarket parts bolted on to it?

Rick Brandt

The Jeep has 190,xxx on it. No aftermarket add one other that lift and tires/ rims. I have little to no oil lost between oil changes. What I do loose I think is from the oil pan leak. A compression check was done on the Jeep and all cylinders are between 175-180 psi. Even the dealers are stumped on this one. I'm afraid of it burning down if I keep driving it. Engine is running at 195-200 so not overheating. Guess it's time to start throwing parts at it.