Folks,
Out here in the Denver area we’ve been having a heat wave of sorts, temps just under 100 degrees which for us, even in the summer, is hotter than normal. I say this because it might be a clue to something I experienced yesterday in my ’06 LJ.
Randomly, and concurrent with the hot weather, well after the engine has warmed up, the Jeep has shown me the Yellow Engine Icon of Hell on the dash and since I have a scan gauge hooked up at all times it’s a P0421.
From our friends at Google: The P0421 code on a Jeep means "Warm Up Catalyst Efficiency Below Threshold (Bank 1)." It triggers when the vehicle’s computer detects that the catalytic converter on the passenger side is not cleaning exhaust emissions effectively, usually during the first few minutes of a cold start.
Well this is weird because I’m getting this code well after the Jeep is warmed up, never when it’s cold.
Here’s where things got interesting… Yesterday after work I’m driving along on the freeway, 6th gear, everything’s fine. The top was down and I did not have the A/C on. Suddenly the engine just started to run sluggish. The more I pressed on the accelerator the less it had an effect, I moved over to the right lane and the Jeep is really slowing down, but no mechanical sounds of like rod knock or anything, it just ran really poorly and had zero power. No CEL either. I pulled over onto the shoulder. At this point the engine idled just fine, but wouldn’t rev at all past idle. I got out and checked for leaks, the engine was hot (about 225 degrees) (did I mention the outside air was almost 100 degrees?) so there was gurgling in the radiator and the catch bottle, but no fluid leaks at all. No oil, no connecting rods poking out the side of the block, nothing.
Since I remembered I had those random P0421 codes that pointed to the cat cons I walked around to the back and put my hand to the exhaust. Almost no air coming out - not the normal puff puff puff that it makes and then I realized that the exhaust was quiet. I have a 4.6 stroker and 2 1/2 inch pipe all the way to the back, so it’s always made a rumble, but nothing. I honestly think I have a plugged up cat con.
I walked down the freeway to the next exit, called an Uuuuber for a ride home, got my truck and came back and flat towed it home. Of course by the time I unhooked to put it in the garage, the engine was seemingly OK, still doesn’t want to rev very high and almost no air coming out the exhaust. A quick bit about the history of my cat cons - three years ago I had some serious engine problems and the Jeep was running so rich fuel was just pouring into the cylinders and the crankcase, long story short the drift pin on the bottom of my OPDA came out, the gear on the cam bounced around, the timing went way off and the engine seized. I put in a new engine but never changed out the cats, because looking into them they looked OK.
Question: Has anyone ever experienced this? Is that typical behavior if you plug up a cat con? I only really made it a half mile in its running rough state, can that damage an engine?
Thanks!
Out here in the Denver area we’ve been having a heat wave of sorts, temps just under 100 degrees which for us, even in the summer, is hotter than normal. I say this because it might be a clue to something I experienced yesterday in my ’06 LJ.
Randomly, and concurrent with the hot weather, well after the engine has warmed up, the Jeep has shown me the Yellow Engine Icon of Hell on the dash and since I have a scan gauge hooked up at all times it’s a P0421.
From our friends at Google: The P0421 code on a Jeep means "Warm Up Catalyst Efficiency Below Threshold (Bank 1)." It triggers when the vehicle’s computer detects that the catalytic converter on the passenger side is not cleaning exhaust emissions effectively, usually during the first few minutes of a cold start.
Well this is weird because I’m getting this code well after the Jeep is warmed up, never when it’s cold.
Here’s where things got interesting… Yesterday after work I’m driving along on the freeway, 6th gear, everything’s fine. The top was down and I did not have the A/C on. Suddenly the engine just started to run sluggish. The more I pressed on the accelerator the less it had an effect, I moved over to the right lane and the Jeep is really slowing down, but no mechanical sounds of like rod knock or anything, it just ran really poorly and had zero power. No CEL either. I pulled over onto the shoulder. At this point the engine idled just fine, but wouldn’t rev at all past idle. I got out and checked for leaks, the engine was hot (about 225 degrees) (did I mention the outside air was almost 100 degrees?) so there was gurgling in the radiator and the catch bottle, but no fluid leaks at all. No oil, no connecting rods poking out the side of the block, nothing.
Since I remembered I had those random P0421 codes that pointed to the cat cons I walked around to the back and put my hand to the exhaust. Almost no air coming out - not the normal puff puff puff that it makes and then I realized that the exhaust was quiet. I have a 4.6 stroker and 2 1/2 inch pipe all the way to the back, so it’s always made a rumble, but nothing. I honestly think I have a plugged up cat con.
I walked down the freeway to the next exit, called an Uuuuber for a ride home, got my truck and came back and flat towed it home. Of course by the time I unhooked to put it in the garage, the engine was seemingly OK, still doesn’t want to rev very high and almost no air coming out the exhaust. A quick bit about the history of my cat cons - three years ago I had some serious engine problems and the Jeep was running so rich fuel was just pouring into the cylinders and the crankcase, long story short the drift pin on the bottom of my OPDA came out, the gear on the cam bounced around, the timing went way off and the engine seized. I put in a new engine but never changed out the cats, because looking into them they looked OK.
Question: Has anyone ever experienced this? Is that typical behavior if you plug up a cat con? I only really made it a half mile in its running rough state, can that damage an engine?
Thanks!
