Cat Delima. Where’s the exhaust section?
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Cooler could mean that side is seeing more fuel on that bank. Do you have a tool to see the LTFTs for each bank? Have you looked at the spark plugs? Exhaust leak near the O2 sensor could make the engine think it's lean on that bank and richen up the mixture. Or could be a leaky injector.
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From: Schiller Park, ILL Member: #317
I took the temp of the cats and the suspect cat which is the drivers side was cooler than the passenger side. The code it throws is always P0420 & the vibrations and rattle come from the drivers side as well. So I was expecting the drivers side to be hotter due a possible clog but that wasn’t the case.
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If it's cooler, that might be because pieces of the substrate have already broken off and blown out clean. The rattle might just be what remains of the loose leftovers. I wouldn't automatically suspect a clog just because it might be coming apart. You could give it a few hard taps with a rubber mallet and see if anything easily bounces around.
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From: Schiller Park, ILL Member: #317
I whacked both of them with a mallet today actually. The test was inconclusive. They sounded about the same except when I tapped the drivers side there was a vibration that sounded like it was coming further downstream. I didn’t hear a rattle inside the cat but I guess maybe the rattle sound could’ve been travling down the pipe.
That was the case with my '02 Z28; just the code, no symptoms with idle or MPG or driveability/power at all. And I left it that way for years/10s of thousands of miles, still no other issues.
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O2 sensors will sometimes develop a rattle, in two different ways: 1) The metal ring near the end (wiring end) of the sensor will sometimes vibrate, this can be solved with some HVAC tape to keep it tight. 2) Something inside the sensor itself is rattling. I've never taken one apart to figure out exactly what/why they rattle, but I had this issue on my '00 car. It was one of the rear O2s (which I had already disabled with sims anyway), so I just removed it and plugged the bung. Rattle went away 100%.
Those temps are too cool for operational (ungutted) cats, and MUCH too cool to suggest any kind of clog. When they get truly clogged, they will get hot enough to glow red, then eventually kill then engine as they won't flow at all. Functional temps should be at least double what you're seeing, even at idle, unless the system wasn't yet up to operating temp.
That was the case with my '02 Z28; just the code, no symptoms with idle or MPG or driveability/power at all. And I left it that way for years/10s of thousands of miles, still no other issues.
Those temps are too cool for operational (ungutted) cats, and MUCH too cool to suggest any kind of clog. When they get truly clogged, they will get hot enough to glow red, then eventually kill then engine as they won't flow at all. Functional temps should be at least double what you're seeing, even at idle, unless the system wasn't yet up to operating temp.
That was the case with my '02 Z28; just the code, no symptoms with idle or MPG or driveability/power at all. And I left it that way for years/10s of thousands of miles, still no other issues.
Joined: Nov 2001
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From: Schiller Park, ILL Member: #317
