i cant figure out whats going on with my egr. if i disconnect the vacuum line, and plug it, form it my truck runs great. if i connect the vacuum line up it will surge between 40 - 50 mph. i replaced the egr valve, egr position sensor and the evr vacuum solenoid. now the bok says to connect a vacuum gauge to the outlet port and a vacuum pump to the inlet port and the vacuum should hold, with the elect. disconnected to it. well it didnt hold and i went and bought another one and it doesnt hold vacuum either. theres another smaller vacuum/elect. valve next to it but this one im checking is the one in the picture, it goes to the egr. did i get a bad valve or am i doing something wrong.

 

What's the condition of not just the EGR vac line, but all of them? They could be getting old enough that they're starting to crack and sucking more air when the engine gets warmed up.

 

all bad vacuum lines have been replaced. strange thing is even with the hose plugged with a ball bearing and if i put it back on it will surge but less. so maybe to much back pressure, oh thats right i checked the back pressure and only had about 1&1/2 lbs. its a strange one.

 

https://www.ford-trucks.com/forums/8...egr-valve.html

 

thanks for the link, a lot of info. there. right now i just have the hose removed and plugged. no check engine light and it starts and runs great. i understand why a lot of people get the eliminator because of a check engine light problem. im checking my mpg today to see if theres any difference. im not sure why the egr has to have a block off plate if it not leaking. it still a puzzle why it does what it does and it would be nice to figure it out. i think its something minor but almost impossible to find, unless some one has had the same exact problem and fix i may never figure it out.

 

well i just did the math, twice, and i went from 15 mpg to 17 mpg, thats with the egr vacuum line connected to disconnected, id say im lucky that my truck is one of the ones that mpg improved with it unhooked. guess life is good sometimes.

 

From my experience, the EVR doesnt hold vacuum. The EGR valve vacuum motor on the other hand will and should hold vacuum when hooked directly to a vacuum source. If it does not hold vacuum then you have a faulty EGR vacuum motor. Either the leak is in the vacuum motor seals, or the casing. I sealed my EVP to the vacuum motor with a gasket maker compound to make sure it wasnt a leak source.

The EGR blocking plate is for looks IMHO. You can accomplish the same thing by placing a piece of sheet metal cut to the right size between the EGR valve and intake manifold to block the port. The engine wouldnt know the EGR isnt working unless you have the newer system that needs the exhaust to flow through the egr tube.

 

The main reason for the block off plate and plug is to clean up the engine bay a bit.
The EGR system is completely useless other then emissions.

The only thing it does is re-introduce unburnt fuel back into the intake manifold in the form of gasoline soot and motor oil.

My friend Josh said it best,
Here is his EGR after 100k,


And here is his intake,


And here's the difference cleaning his made,


And yes, he deleted his EGR completely.
That's why everyone gets rid of them.

Here's my throttle body @ 180k during my rebuild.
(Left, after cleaning. Right, before.)


There's some food for thought!
Good luck!

 

well thats what messed me up, the haynes manual says to disconnect the elect. to the evr and put a gauge on the outlet port then apply vacuum to the inlet and it should hold vacuum. it didnt so i figured that as the problem, well the new one didnt either and i figured out it must hold vacuum when the voltage is applied. funny though the book also says that i only have a evr but in fact i have a evr and another elect. vacuum solenoid mounted right next to it. that one goes to the smog pump valve mounted up top. oh well its running great and better gas mileage too. as for looks, well i have the 4.9 and its half way hidden at the back of the manifold. as for the carbon buildup, i wondered why there was carbon in the intake and throttle body, after all the injectors are way down at the head and only air goes through the throttle body and intake. im just glad it solved a problem, that i couldnt figure out, and help with the mpg.