pick your brain regarding a tune

[Doubeleive]

i have a 92 tune from @BlackBearPerf and have had it for a while and everything is fine with it
However for the last 5-6 tankfulls I have been putting in e85 (instead of 92) and it has been running fine
yesterday I got a p0420 cat code on a cat that is only 5 months old and about 6k miles on it.
I am curious if the cat code could be related to me running e85 while on the 92oct tune?
all sensor data and fuel trims seem to be fine, no misfire's or anything, purrs like a cat.
any idea's?

 

[George B]

Flakey o2 sensor?

 

[Doubeleive]

Flakey o2 sensor?

maybe but I didn't notice anything just idling looking at the signal

 

[tooleyondeck]

this may sound overly simple but are your new cat(s) welded in? If not, have you checked for a leak near the bank 1 O2 connection?

 

[BlackBearPerf]

Running E85 shouldn't trigger a cat code so you should be fine in that regard. Do you have a cam by chance? If so, they can burn through cats fairly quickly even though 5 months is not that long. It could be a bad O2 sensor that is triggering that code. Is it an aftermarket cat? They can work just fine but not read efficiently.

 

[Doubeleive]

this may sound overly simple but are your new cat(s) welded in? If not, have you checked for a leak near the bank 1 O2 connection?

it is welded in and since it has been welded in I have been hearing a small leak at cold start up, but it goes away after about 20-30 seconds and doesn't return until it has sat and been cold for 8 hours. I am dropping it off at the shop that installed it this afternoon so they check it in the morning when it is cold, I have told them about the leak before but they can never find it because it only happens when it is cold and doesn't appear to be the manifold. It has been like that for 5 months and the code did not show up until after I started running e85, so I am just wondering if it has anything to do with the tune for 92 and running higher octane e85 instead

 

[Geotrash]

it is welded in and since it has been welded in I have been hearing a small leak at cold start up, but it goes away after about 20-30 seconds and doesn't return until it has sat and been cold for 8 hours. I am dropping it off at the shop that installed it this afternoon so they check it in the morning when it is cold, I have told them about the leak before but they can never find it because it only happens when it is cold and doesn't appear to be the manifold. It has been like that for 5 months and the code did not show up until after I started running e85, so I am just wondering if it has anything to do with the tune for 92 and running higher octane e85 instead

Here's an interesting one:

The Effects of Ethanol on a Catalytic Converter

This question of ethanol and catalytic converters is one of the more interesting chemical quandaries on Planet Car. Yes, ethanol can damage a catalytic converter -- but probably not in the way you're thinking, and not directly. Believe it or not, how ethanol affects your catalytic converter may...

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[Doubeleive]

Running E85 shouldn't trigger a cat code so you should be fine in that regard. Do you have a cam by chance? If so, they can burn through cats fairly quickly even though 5 months is not that long. It could be a bad O2 sensor that is triggering that code. Is it an aftermarket cat? They can work just fine but not read efficiently.

it might be a sensor then I am going to try and do a log file and see if anything is out of whack, the cat is aftermarket, both are actually had them replaced once about 3 1/2 years ago and the left one went bad so had a new one installed in May of this year. the 02 sensors were all replaced at 95k with (oem) and now have about 75k on them.
I have burned thru cat's before in about a year and half on a previous vehicle, never in 5 months!. no cam installed it's all stock except a cai

 

[tooleyondeck]

it is welded in and since it has been welded in I have been hearing a small leak at cold start up, but it goes away after about 20-30 seconds and doesn't return until it has sat and been cold for 8 hours. I am dropping it off at the shop that installed it this afternoon so they check it in the morning when it is cold, I have told them about the leak before but they can never find it because it only happens when it is cold and doesn't appear to be the manifold. It has been like that for 5 months and the code did not show up until after I started running e85, so I am just wondering if it has anything to do with the tune for 92 and running higher octane e85 instead

Dumb question, but do you not have a flex fuel sensor?

 

[BlackBearPerf]

it might be a sensor then I am going to try and do a log file and see if anything is out of whack, the cat is aftermarket, both are actually had them replaced once about 3 1/2 years ago and the left one went bad so had a new one installed in May of this year. the 02 sensors were all replaced at 95k with (oem) and now have about 75k on them.
I have burned thru cat's before in about a year and half on a previous vehicle, never in 5 months!. no cam installed it's all stock except a cai

You can definitely do a data log for us and we would be happy to review it for you to see if we can identify anything.