dynatechs and their cats on 07 nnbs 6.0 in signature

code po430, cat effiecentcy below threshold...
common causes, exh leak- none
plugged cat, brand new

called dynatech and they told me to raise rear 02 out of exh stream, didn't make sense to
me but, i did that, light still comes on.
i also put a shorter bung in the pipe to get more exh stream, that didn't help.
light comes on after about 3 days, numerous driving cycles.

I 've got an Otc scanner at work , all looks ok, hpt logs look ok.

Question, can i change the threshold with hpt somehow for the rear 02's to get the light out, i don't really want to disable 02's if i don't have to.

 

WOW, they told you to raise it out of the stream. WOW, I can't believe they said that. Dynatech telling you to fool the pcm into passing emissions.

With that said, get one of the GM guys to post a troubleshooting process for that code, but if you just put that system in and it was fine before I want to say you need to check all the wiring. Nothing pinched, cut, harness not clipped in all the way, something along the path of that wire from the pcm to that particular sensor. If you have cats and the both the sensor and cat is in good shape, it should be fine. All the pcm is looking for is a difference (albeit certain range) in the afr after the cat.

 

pm chevracer83 or Torque_Wrench and see if they can shoot you a step by step troubleshoot. Below efficiency doesn't seem like a resistance or wiring issue but you just did the install

 

done all the trouble shooting, i have alldata at work, trouble tree as long as your arm.

only other thing.,. the headers came with a pigtail extension for the 02 that is setting the code, passenger rear, could that do it??????????????

 

yes. ohm out the extension. post what the ohm readings are on each wire.

 

.3 ohm on all 4 wires


i'm going to try and pull enough of the oe harness thru so i don't have to use the extension or move the 02 forward

 

hopefully that's it. sensor isn't banged up? swap sensors around. see if the code follows the sensor. 430 is bank 2, swap em see if you get a bank one code.

 

i can try that too, trouble is takes about 3 days to set the code...

 

most high flow cats are not efficient enough to pass factory emmissions. get the codes deleted with tuning and it will be just fine.

 

P0420 and P0430 needs to be disabled in the PCM if you run no cats