Cat efficiency on both banks

[Wardie]

Hey guys! First post of many to come. I own a 2004 imola sedan. With ~130k on the clock.

I'm having some issues tracking down the cause of the p0420 and p0430 codes. I've replaced the 02 sensors and put on lower mile cats.

I've searched around for quite some time trying to find out why, but about 99% of posts are for only one bank having codes. Never both at the same time. I was curious if anyone has any input or maybe knows why this would happen. It's very strange.

My car does consume a decent amount of oil, I am not sure if that could relate.

Thanks

[Vas]

You replaced both the pre-cat and post cat sensors? Also is your maf sensor sill original?

How much is a decent amount of oil? CCV system been replaced and typical leaks like the OFHG?

[Wardie]

Yes all sensors. To my knowledge the maf is still original. I've only owned the car for a few months.

The oil light comes on every 1500-2000 miles id say I just topped it off yesterday, I'll keep track of the miles

Haven't noticed much in the way of ccv leaks, my idle isn't effected so didn't think of that may being a problem.

[Vas]

Yes all sensors. To my knowledge the maf is still original. I've only owned the car for a few months.

The oil light comes on every 1500-2000 miles id say I just topped it off yesterday, I'll keep track of the miles

Haven't noticed much in the way of ccv leaks, my idle isn't effected so didn't think of that may being a problem.

There is a possibility that the maf sensor could be the issue.

As far as oil use, that is a nice good bit. How much oil did you add in that amount?

I was just suggesting to make sure you do not have an oil leak somewhere so you could rule that out. Stuff like the oil pan gasket or the oil filter housing gasket.

Any maintenance history on the car from the previous owner?

[Wardie]

Maybe I'll try giving it a good clean and see if that helps at all before I go buy a new one.

I'd say maybe a quart or less. I've never seen oil on there ground but I've seen a small spot hanging off the oil pan, the gasket is new. I know the valve cover has some leak marks on it. Nothing to constitute a quart though.

There a good about of dealer paper work from the last few owners. I'll rummage through them later today.

[danewilson77]

Welcome. I have zero oil consumption and 0420/30 codes. Just more data.

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[Wardie]

Welcome. I have zero oil consumption and 0420/30 codes. Just more data.

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Perfect, thanks. If these codes aren't a big deal I'll just focus my money on something else. I just didn't want the engine to get damaged by plugged cats or something else.

[danewilson77]

If cats were plugged, I think you'd have a noticeable difference in performance.

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[Wardie]

That's what I figure but I wanted to be safe. You think a bad fuel pump could cause this? I'm just trying to figure all possible options. I just replaced spark plugs.

I can't see it being any sort of vacuum because the idle is fine.

[danewilson77]

What other indications do you have of a bad fuel pump?

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[Wardie]

What other indications do you have of a bad fuel pump?

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Not sure, I changed out the fuel filter when I bought it and it wasn't pretty.

Found paper work that says 2-14-14 it says " Programmed vehicle for oxygen sensor as per customer request. Currently the **CHECK ENGINE** warning light is not on."

Something about a DME module programming for O2 update?

[johnrando]

Welcome. Hope you sort it out.

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[danewilson77]

Wardie, any update here?

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[Wardie]

Hey all, sorry for the serious lack of updates I was really trying to keep this thread updated.

So, I still have the codes! I have emissions coming up soon, I got thermostat and coolant sensor coming tomorrow to verify the engine temperature is correct. Ive also done the CCV a few months ago. I replaced the cats with known working 80k mile ones, and the codes came back within a few months.

Im also starting to get a real rough idle when going to a stop. Real low RPM, just a standard stop. Its shuttering a bit then once I've fully stopped it recovers. Figure it might be ICV, or possibly a vacuum leak somewhere that is causing all this chaos.

Ive also noticed the engine trim is anywhere from -0% to - ~6% so it is running a bit rich. (I'am sure this is the main culprit)

-MAF?
-Coolant Temp?
-Vacuum Leak?

Dane did you ever figure out this mystery? If it comes down to it I will just simulate my O2s to get past emissions but I would ultimately like to get this fixed.