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Discussion Starter · #1 ·
Before I ended up blowing my original motor I installed new CAT’s all the way around. Now that I’ve had the new motor put in I have a CEL for P0430... what the hell man.. is it time to replace all the o2 sensors now?! I wish I would have just deleted ALL 4 of these pain in the asses.. but hindsight, am I right?
well any help on tips, tricks, advice would be really appreciated!
 

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What brand cats did you install? How many miles are on your current O2 sensors? Could be time to replace them, but if you went cheap on the cats it's very possible they are already toast.
 

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The downstream sensors are the only ones that measure emissions, so worst case is you need a downstream sensor. The upstream ones control all the engine controls affecting A/F mixture, so if they were gone you would be getting a rich/lean type code or at minimum high or low LTFT's - which may also lead to a P0430 code, but you would need to have all of them at the same time - not just the P0430.

Are there other pending codes?

If you used aftermarket cats a lot of guys end up with ghost codes occasionally. Did you reset it to see how long before it comes back?

It could possibly be a exhaust leak - most likely where the cat mates to the exhaust manifold. If it were after the first cat it would make your emissions look better, not worse.
 

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"Catalyst system efficiency below threshold (Bank 2)"

Not typically caused by a faulty sensor. Primary cat on bank2 may need cleaning or replacement. You can check readings of secondary sensor to confirm. Normal running should see very little oxygen, inefficent cat will show a lower reading indicating oxygen less chemical reaction in the cat

 

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Discussion Starter · #5 ·
The downstream sensors are the only ones that measure emissions, so worst case is you need a downstream sensor. The upstream ones control all the engine controls affecting A/F mixture, so if they were gone you would be getting a rich/lean type code or at minimum high or low LTFT's - which may also lead to a P0430 code, but you would need to have all of them at the same time - not just the P0430.

Are there other pending codes?

If you used aftermarket cats a lot of guys end up with ghost codes occasionally. Did you reset it to see how long before it comes back?

It could possibly be a exhaust leak - most likely where the cat mates to the exhaust manifold. If it were after the first cat it would make your emissions look better, not worse.
I did and it is about 300 miles before it comes back on...
 

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Discussion Starter · #6 ·
What brand cats did you install? How many miles are on your current O2 sensors? Could be time to replace them, but if you went cheap on the cats it's very possible they are already toast.
The fronts are from Yitamotor.com and the rear ones are from exhaust distribution. There are about 200K on my O2 sensors that I have now.. I’d hope my new cats aren’t toast that would be a massive freakin headache especially since they have less than 3,000 on them... would 02 spacers help? Or should I break down and get new o2 sensors?
 

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Discussion Starter · #7 ·
"Catalyst system efficiency below threshold (Bank 2)"

Not typically caused by a faulty sensor. Primary cat on bank2 may need cleaning or replacement. You can check readings of secondary sensor to confirm. Normal running should see very little oxygen, inefficent cat will show a lower reading indicating oxygen less chemical reaction in the cat

Well all of mine have less than 3,000 miles on them, could it be the o2 sensors need spacers or should I just replace them?
 

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Discussion Starter · #8 ·
The downstream sensors are the only ones that measure emissions, so worst case is you need a downstream sensor. The upstream ones control all the engine controls affecting A/F mixture, so if they were gone you would be getting a rich/lean type code or at minimum high or low LTFT's - which may also lead to a P0430 code, but you would need to have all of them at the same time - not just the P0430.

Are there other pending codes?

If you used aftermarket cats a lot of guys end up with ghost codes occasionally. Did you reset it to see how long before it comes back?

It could possibly be a exhaust leak - most likely where the cat mates to the exhaust manifold. If it were after the first cat it would make your emissions look better, not worse.
I had to have the front ones welded in so I doubt a Leak up there I will have to run codes again to double check and get back to you... I did reset and it came back at about 300 miles.
 

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The fronts are from Yitamotor.com and the rear ones are from exhaust distribution. There are about 200K on my O2 sensors that I have now.. I’d hope my new cats aren’t toast that would be a massive freakin headache especially since they have less than 3,000 on them... would 02 spacers help? Or should I break down and get new o2 sensors?
Those definitely are some cheap cats, but they should last more than 3k. O2 spacers won't fix anything, they will just mask your problems. They basically just trick the computer to think everything is working ok. I'm not sure why guys use those, you'll have to look it up.

New O2 sensors wouldn't hurt if you have 200k on them. Do yourself a favor and get quality parts, not Amazon/Ebay cheap ones - they're known to last a very short time.
 
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