EGR VALVE BLOCK OFF PLATE

[geoffinbc]

Many people have passed with the EGR off, and one of the members here is failing emissions (NOx to be exact) and the numbers went DOWN with the EGR off. Go figure. Don't tell me it will never pass cause it has and will.

The performance advantage of the EGR off is simple. With it on, the exhaust gases collect as carbon deposits on the backside of the intake valve. This restricts the flow and also absorbs some of the fuel from the injector. Tell me that doesn't hurt performance! Also, my gas milage didnt change for me when I turned the EGR back in, which was a disappointment. There are exceptions, as my car was one. Normally you should gain a mpg or 2 with the EGR on because the digital EGR is what the fuel constant table is based on, and it lowers the constant with the EGR on which means it spits out less fuel when its engaged. My car just didnt care too much I guess. With vacuum EGR, there is no such change in the tables so it would take the O2 sensor to detect the changes and lean the injectors out to compensate.

True you might get past emissions with no EGR. Depends on the test though. Was it an idle test or a more in depth road test where the car is actually put under a load? Other variables like ambient temperature, engine temperature and the fuel you are running will effect it. Gas with alcohol in it will burn cooler. NOx emissions depend completley on combustion temperature, so it will vary alot depending on how hot things are.

If the combustion process in you car is burning good and clean and the gas you run is of good quality then there should never be excessive carbon buildup on the intake valve. Also the condition the car is driven under makes a big difference. If you run to work and back once a day and it never gets hot then carbon will build up. Also if it runs too rich carbon will build up.

I have had 4 60degree V6's apart within 2 years and none had any carbon buildup to speak of. 2 were aluminum 2 were iron and they all had EGR.