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Check engine codes continuosly for left bank catalytic converter failure

i have replaced the catlytic converter to great expense…and all the O2 sensors…but it keeps coding for left bank cat failure…chrysler wont give any hints and i dont want to go to the dealership and pay bongo bucks especially after replacing the cat already…PLEASE HELP…4 expert analysts are stumped also…oh and the engine had a complete rebuild c/w apporpriate upgrades after severe bearing noises developed…perhaps the PCM needs a complete software reboot?..also gas mileage varies distinctly before and after coding…could it be bad injectors?..wouldnt that show a code?

I’m not going to say this is your answer, but I can see bad/leaking fuel injectors causing some of these problems:

  1. You’ll get excess gas in your engine, particularly at startup, which won’t be burned properly. That gas may burn very well later in your cat, and that can cause it to overheat, melt, and fail

  2. You won’t be metering your gas properly, meaning your fuel economy may be abysmal

  3. If it leaks enough and gets past the valve stem and piston rings and mixes with the oil, you might destroy the lubricating properties of the oil and that could lead to bearing failures.

Depending on severity, this may not create a code… its more likely to if its bad enough to cause a misfire, I would think… Checking them shouldn’t be too hard, but you will need to check all 6 (may be able to check all at the same time simply by monitoring fuel pressure with the engine off to see if it drops quickly)

there is never a misfire…occasionallly it will ping on hard uphill climb, and i use 92 octane gas…it hates the cheap stuff…wouldn’t it code for bad fuel injecture(s) if that was the issue?

Unfortunately, no, it wouldn’t necessarily code for a bad fuel injector(s).

In fact, I’m not aware of any car that has any code in its OBD system directly related to fuel injector performance. I can’t think of a single one that directly monitors the injectors. A fuel injector fault would generally be detected by a misfire or an O2 sensor if its going to trigger a code at all. And those codes won’t tell you that an injector went bad - it will just tell you something isn’t right.

When I had an injector go bad intermittently, it set a code for a misfire and for a lean condition in the exhaust (ie, the cylinder didn’t fire because no gas came in, and then the O2 sensor detected a rush of air with no exhaust fumes).

Again, I am NOT advocating that this is the problem, but it certainly could explain a lot of your issues and is worth investigating, as PART of an overall proper diagnostic technique.

You have to see if the issue is the messenger or if the message is real. What tests have been performed to verify the 02 sensors and cat. are working as designed? Has it been verified that these components are working correctly? there are techniques to confirm both 02 sensors and cats. are working,aside from a generated code,OH by the way,what cat. code? have you checked TSB’s?

Easy way to test if its the fuel injectors is to simply switch them from the left bank over to the right, and vice versa. If the codes then travel with the injectors, then you know one of them is having issues.

Since the engine was just rebuilt, I would actually be looking for an intake leak on that bank of cylinders, or a faulty seal around the injectors.


one analyst, with his computer managed to detect 2 injectors out of voltage range, but it could not indicate which injector(s)