i parked my 150 for a few years and didnt drive it much until recently. power was down and fuel econ. was terrible so i tuned it up and checked the codes. it was throwing code 33 and a couple other egr related ones. endend up replacing egr valve, control solenoid, and egr positioning sensor. power is better but still not like it was and mileage is way down. cleared memory and ran codes again. now i am getting code 334- egr closed voltage higher than expected. also my chiltons says i should be getting vacuum at the line that plugs into the top of the egr valve, i am getting like 2 in hg. it says it should be 5 at idle more as rpms increase. this is getting frustrating. any help would be greatly appreciated. thanks.

 

Sounds like the EGR position sensor may not be installed correctly. Possibly the gasket on it is too thick. Since the voltage is too high the computer is trying to close the EGR by removing vacuum, which is why you are getting vavuum readings that are too low.

 

I had to fiddle with mine too - if it's getting higher voltage than expected, try backing off the screws that mount the sensor (not enough to lose seal, but you have some room to work with). If that's not enough to keep it happy, you can add a second gasket under the sensor.

 

ok, i installed the new gasket that came with the sensor. i was using the original one because it looked fine. it may have been slightly thicker. still have the same vacuum.any other ideas? thanks.

 

Have you checked the connectors from that vacuum plug back to the solenoids? There are two or three connections as the line goes behind the intake manifold. You could also have a crack in that plastic line somewhere.

 

Did you clear the codes and recheck them after driving the truck some to see if the code 334 is gone? If the code is still there then the sensor problem has not been corrected. Remove and cap the line to the EGR valve (after clearing codes) and drive the truck a bit. Recheck for codes, you should get code 332 (Insufficient EGR flow detected) but not get the 334.

 

ok i doubled the gasket that gave me zero vacuum. i inspected the line as best as i could, kinda tricky, i think its ok. i checked the vacuum at the control solenoid and it registered the same as at the egr valve. at idle its 0 rev the motor it jumps to 2 or 3 no higher. i cleared the codes and plugged the line at the egr and drove around the neighborhood for 10 min. and got code 334 again. also when i had the position sensor off i started the motor and revved it up, looked and stuck my finger down the egr and didnt see or feel and movement??? isnt it supposed to raise?

 

It's not gonna move with the sensor off - it relies on vacuum to help it open.

Check EGR movement with everything back together - with the truck idling, give a tug on the throttle cable linkage and watch the bottom of the egr valve through the little holes around it. You should see it open as the idle increases.

 

when i rev the motor pretty high it moves about an 1/8 of an inch

 

Is it closing all the way? Where you could see it moving at the bottom - when it closes, can you still see the silver shaft coming up? I had that problem with mine, and the parts store replaced it with no question. Brand new egr valve, stuck partially open.

The only other thing that I've experienced is the sensor itself - they come in 2 colors - grey and black. You'll want to be sure the new one is the same color as the old one. The different colors run on different voltage.

Either one of these could be causing the computer to see more voltage than expected when the valve is closed.