Cat replacement
 

Long story short:

Had a honeycomb breaking loose on the driver side cat, no check engine light. Put a set of 200 cell high flows from flowmaster on and now I have a check engine light. A few people had mentioned to me that they ran 200 cells with no problems, didn't work for me. Anybody have any suggestions for cats to get rid of this engine light now?

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Have you tried one of those spark plug adapter extensions? I don't remember what they're called but apparently there have been good results...

Tried the angled elbow ones stacked with plug non-foulers, still have the light.

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What error/s


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Typical O2 sensor errors, cat inefficiency.

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I started getting fuel trim cat errors. I'm looking into the possibility of cat simulator for post cat. My truck doesn't need smog testing after next year anyhow.


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I'm trying to keep mine emissions ready, being military I'll never where I'm going to end up.

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I replaced both pre cat about three weeks ago; instantly got a huge bump in mpg which was a main driving force behind the upgrade, but on my first longer trip of 75 miles, my mpg was even worse.

A week later I started getting post cat fuel trim errors and a week later they started every drive cycle!

After hours and hours of searching the net I finally found a mention of reset [fuel] adaptations and yesterday I found the sub menu to do this with the foxwell nt510. Reset fuel trim and reset the code that came back every start for the past week or ten days then drove 75 miles home.

https://uploads.tapatalk-cdn.com/201...705d0d882b.jpg

Woot woot! It worked! Not only no error, the post cat O2 readings that have been stuck at 0.7 volts finally will go as low as 0.1 volts and average very close to 0.45.

Time will tell if it was a permanent fix, but the proof in the photo above where I'm used to seeing 18.5 mpg for the last 3 weeks I'll take a 25% bump in mpg!

What engine do you have? The 4.8 only has two cats per bank.

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M54 3.0