1974 Dart
other than disconnecting the vacuum line what could I have done differently and how necessary is the egr?
The EGR is real easy to test on the car. It is not supposed to function at idle, and not at WOT, and not, a lot of other times. It is only supposed to work on a warmed up engine, and only under light throttle and usually this is at cruising speed.
You can diagnose it's operation with a vacuum gauge plumbed into the line and brought up to the windshield, then go for a roadtest. This,however does not prove it's working, only when it is supposed to be working, and assumes all the other plumbing between the gauge and the vacuum source, is correct and functioning correctly,lol.
To test the EGR valve it self is a 2-parter; first it has to respond to a vacuum by lifting the pintle valve. You can see the valve as a thin rod by looking thru one of the windows in the bracket that attaches the vacuum pod to the casting. Secondly, the valve itself has to be unobstructed by carbon.
To do this on the car, I stick a finger thu a window and physically lift the valve off the seat. If the valve end is open, and the passages to it are open, the engine will usually immediately stall, or suddenly begin to idle very poorly. If the idle doesn't instantly react, then I know the system is not functioning. Which isn't necessarily a bad thing,lol. I wouldn't ever buy a new valve. If I can't get the old one to work, then so be it. Test 2 is the same except using engine vacuum to engage the diaphragm, bypassing all the controls or by using a vacuum pump, or by just sucking on the hose, looking for a ruptured diaphragm. A vacuum leak here is usually not even noticed if the system is otherwise functioning correctly.
Ok now a few words about that devilish device. The idea behind it is to introduce previously burned exhaust gasses into the chambers to reduce the combustion temperature in the chamber. They say this exhaust is cooler than what goes on in the chamber.They say the reason they do this is to reduce the creation of NOX, which they say is an atmospheric pollutant. They say a lot of things I don't believe.
Ok but wait, why do we burn gas in the first place? Hyup to create hot gasses that will push down on the piston and ultimately propel our vehicle down the road. And the hotter the gasses the greater the push right.
But this device is only supposed to work at very small power settings, and in more or less steady-state conditions like cruising. So they say we won't miss the energy. Tell that to your gas gauge.
If it don't work and ain't stuck open, I'm not gonna lose any sleep over it. Governments all over the face of the earth have done far greater damage to our atmosphere, and continue to do so every year. IMO, that device is just there to increase our fuel consumption, to keep us slaves to the oil barons,lol. End rant.
