FRUSTRATED! Please help!

MMAFIGHTER121

MMAFIGHTER121

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OK, so I've been troubleshooting a p0430 code (cat below efficiency bank 2) and an incredibly high short term fuel trim on bank 1 (30+%) but a normal short fuel trim on bank 2 (which I found weird that the lean bank wasn't throwing the code), The cats are thunderbolt high flow and only 2 months old, all 4 O2 sensors are about 2 months old as well (so I doubt they've gone bad already). I visually checked and then sprayed about carb cleaner at several lines and around bay to hunt for vacuum leaks and found nothing, the intake is sealed up tight (no post MAF leaks) and I tested the voltage on my MAF and it seemed to be working fine as well (gaining voltage as I rev). There is no tangible misfire and it seems to run smooth enough, no sputtering, no issue starting up either. It might be a tad on the sluggish side, but there aren't any real driveability issues, but I do seem to lose about 1MPG. What on earth ELSE can I check?! What could be wrong?
 
Nothing particularly noticeable. Hard to tell from the inside with the exhaust system I have on
 
My first stab would be swapping the O2 sensors left/right (both before and after the cat) and see if the issue follows the sensors. If not, then you cat may actually be bad, or something even more interesting (injector problem, ignition problem, rag-in-intake problem....)
 
Ugh. That was my next step too.. I just really didn't want to do it...
Quick odd question though - anyone have a photo of where each O2 sensor plugs in? I saw a thread elsewhere on a charger forum where someone switched the upstream and downstream plug and they had gotten a similar reading issue. I strongly doubt it, but why not double check.
 
The downstream plug into a harness that is on the bottom of the tranny. Really hard to mess up.
 
ok - oddness. I reset the ECU after the various tests and the code came right back on, but I didn't have a chance to pull the PIDs immediatly, the scan tool is my friends and I didn't have access to it. SO I pulled the code today - p0430 - but all of my o2 short trims were right in line, same with the o2 voltages.. long trim was only at about +5% and raising as it idled even though short term is in that 0 range... I'm running it now to see if the code returns... what is goin on?
 
Okay, so it's back to the obvious answer. Your aftermarket converter even though it is new, is not working well enough.
 
seems that way dunnnit. at least they're cheap. weird because several other members used thunderbolts without issue.
side note: got underneath and no exhaust leaks.
 
Reset the computer, 40 miles later - check engine light. I haven't pulled it but id assume p0430. I'll switch the O2s and see if the error switches next, then after that its the cat. Just seems odd. I figured a bad cat would give more driveability issues.
 
MMAFIGHTER121 said:
Reset the computer, 40 miles later - check engine light. I haven't pulled it but id assume p0430. I'll switch the O2s and see if the error switches next, then after that its the cat. Just seems odd. I figured a bad cat would give more driveability issues.
Click to expand...

A clogged cat will give drive-ability issues, but one with ineffective catalyst will cause no engine problems whatsoever. The engine doesn't care what's going out the tailpipe.
 
just a brief update - because i'm poor and I want to make sure - pulled the codes after work and got Lean bank 1 and Cat below Eff bank 2.. which leans me back away from bad cat it seems odd that the O2s read fine at idle, the code usually throws after cruising around 50-60... still have to get a shot to swap around O2s and see what happens though.. they're under warranty
 
ha. right. well. I got underneath to swap the o2s to see if the code would move. When I got the post cat sensors out I noticed they were completely different sensors left to right. Autozone gave me 2 different O2 sensors. Yes, I should have paid more attention when putting them in, but... cmon. Anywho, a quick exchange later and I now have gthe correct sensors in and hope the code won't return again.
 
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