P0420 and p0430 after dod , performance parts and tune

[uk tahoe]

hi all , done dod delete, added longtunes , highflow cats , cold air intake , btr stage 2 cam , on my 2007 5.3 tahoe its been tuned , not driven it for aweek since tuned was on my way to bodyshop and just felt a little off engine light came on p0420 and p0430.

Any one else had this problem ? Had a search and comes up with various reasons longtubes,hiflow cats , tune , but want to see if any one has had this and what they did to cure it .

Any help much appreciated

 

[CaptainAmerica1]

Catalytic converter efficiency error code. You missing some 02 sensors? The tune may be way off which would explain it… data log, retune, lather, rinse, repeat till the tune is right…

 

[uk tahoe]

The tuner will not alter any thing to do with the codes so I guess I'm gonna have to find another tuner not happy as more cost thing is they knew I had hi flow cats to start with aswell .

 

[uk tahoe]

Sorry forgot to answer this , still running all 4 o2s with the highflows

 

[Mickey_7106]

That's a common code when you install long tubes, your tuner should have known that. On my C5 What i ended up having to do is swap the rear O2 sensors to the front. You're going to need some pigtail converters since the plugs won't match.

 

[Mickey_7106]

Catalytic converter efficiency error code. You missing some 02 sensors? The tune may be way off which would explain it… data log, retune, lather, rinse, repeat till the tune is right…

I believe no amount of tuning can fix those codes other than turning off the CEL for the front O2's. Since the 02 sensors are pushed back from their original location, they don't warm up fast enough in the short amount of time that's required. Think it's something like 30 seconds

 

[MrBishop]

The catalyst diagnostic measures O2 storage of the converter. The high flow ones obviously don't store much. This measurement is done at idle after the cats are hot and some air flow has gone through them. The fuel mixture is sent rich (or lean). The front sensor will read high (or low) and the rear will follow. Then the mixture is swapped to make the front sensor swing the opposite direction. How long the rear takes to react to this change is the O2 storage of the converter. If it reacts too quickly, you get the codes. With good cats, the front O2 toggles between 0-1 volt, the rears hang, usually around 600-700 mV. GM fueling can use the rear O2 for precise fueling so changing cats will require a recal or just turn off rear fuel trim.

 

[Geotrash]

The catalyst diagnostic measures O2 storage of the converter. The high flow ones obviously don't store much. This measurement is done at idle after the cats are hot and some air flow has gone through them. The fuel mixture is sent rich (or lean). The front sensor will read high (or low) and the rear will follow. Then the mixture is swapped to make the front sensor swing the opposite direction. How long the rear takes to react to this change is the O2 storage of the converter. If it reacts too quickly, you get the codes. With good cats, the front O2 toggles between 0-1 volt, the rears hang, usually around 600-700 mV. GM fueling can use the rear O2 for precise fueling so changing cats will require a recal or just turn off rear fuel trim.

Really appreciate your contributions here. Having first-hand knowledge of the way these systems work from an engineering perspective is great to have and an asset to this community.

 

[MrBishop]

Really appreciate your contributions here. Having first-hand knowledge of the way these systems work from an engineering perspective is great to have and an asset to this community.

I've worked for 3 OEM's and honestly, GM is the best one when it comes to making things work and be simple. I've worked with a lot of very intelligent people, and although there are some lazy engineers, GM had the most good ones, 9 out of 10 I would say and I have no problem telling you where they messed up, even me. I spent all of my time in the calibration community and since I don't work there anymore, I can spill my guts .