Hey guys,

This is a quick question for my education. Will any codes be thrown if you block off the corragated tube at the manifold and don't actually delete any components?

Thanks,
Anthony

 

OBD-II might complain, but OBD-I might not. It is not specified what you are working on. Either way, I guess the answer is might.

 

Haha, sorry about that. These are single cat MAC's going on a 97 T/A. The only thing I could think of might be the EGR code that you get from when you delete cats and there isn't enough back pressure anymore. I wasn't sure if that was EGR valve specific or to the system in general.

 

There is a diagnostic that detects EGR flow to the intake manifold. At very steady engine speeds, the PCM cycles the EGR valve, and looks for an expected change in manifold absolute pressure (MAP) as evidence of EGR flow. If it doesn't see the MAP change as expected it will set P0400 in OBD-II (90+% chance of getting the code), or DTC 32 in OBD-I (probably a 20% chance of getting the code).

Using a very low back pressure exhaust system reduces EGR flow, and would produce the same codes.