Since typing my last post, I took the truck for a quick drive (10 miles or so). It ran rough and crappy for about the first 6 miles, then smoothed out and ran right. The more I think about it, maybe it is electrical...

I guess there's the chance that the rough ride was the 're-learning' period for the computer, or the valve trying to 'loosen up', but I have a suspicion that this will go back and forth every trip like it has been. I sure hope I'm wrong!

This is almost full circle - we started with vacuum lines, sorted all of those out, went through the components one by one, and now we're looking at the wiring. There's nothing left - aside from one of those EGR delete kits to block off the orifices in the intake and exhaust and a resistor to fool the computer!

 

The best I can tell, the gray wire with the red stripe is power. The brown wire with the white stripe is ground and the brown wire with the light green stripe is the signal wire.

 

You really are "The Truck Whisperer"!

I have my meter loaned out to a guy who works for me, but I'll get it back tomorrow. We'll see where that takes us...

Just for good measure - the chilton manual refers to Sig Ret, Vref, and EVP on the 3 wires... would the sig ret be ground, vref be power, and evp be the signal from the sensor?

 

I guess that sounds right, but I was going by the diagrams. In my diagrams, there are several sensors hooked together then hooked to the computer. Since most sensors operate from the ground signal, I figure this is power. Then there are less sensors hooked together and then into the computer. This should be ground because these sensors have a separate signal sending info. The last stand alone wire is the signal.

 

I checked voltage into the sensor as instructed in the chilton book. They indicate between 4 and 6 volts as normal. Damned thing read 4.99 volts...

 

Driving today to and from work, the truck would run fine, then when it reached normal temp, started chugging. After a brief episode of that, it would smooth out again.

Seemed like after giving it some gas to drop down a gear (it has enough power to accelerate or climb a hill if it's a gear too low) the damned thing would uncork and run right again. It didn't seem to be as bad as it had been though, even when it was chugging along - I wonder if I'm onto something about the fitting of the sensor? It felt just right with two gaskets, but after tightening the screws down, I might have lost that extra room.

I'll keep tinkering with it and see what I can figure out.

I keep thinking it's got to be something else, but nothing else could really cause the EGR to screw up could it? I might just have to deal with it and hope it loosens up in time, or go back to the parts store for round 3.

 

Everything you describe still says EGR. Cold- no EGR function, runs fine. Normal operating temperature- EGR supposed to operate, chugging. Wide open throttle- no EGR function, runs right.
See if it loosens if you want, but you paid good money for an EGR that should be working right as soon as you bolted it on.

 

I agree, but I just need a break from the guys at the parts store...

I've spent more time in the parts store or under the hood of my truck than I have spent with my family lately, and it's getting tiresome.

My ADD is kicking in, and I think I'll focus my attention on the sea foam idea in my other post about the valve chatter. That'll give me a fresh issue to worry about, and we'll see if the EGR gets better or worse. It's under warranty for full replacement value for 30 days before they start pro-rating the value.

At this point, I really think that it's moving ok - I tried it under my own suction tonight, and it's much smoother. I think that the real issue is that the sensor doesn't meet the valve correctly and is thinking it's slightly open when it's not. I might be totally off-base with that, but I might as well try to fine tune that and see what I get. I've ruled out everything else, aside from simply another bad valve - I even pulled the exhaust inlet tube and made sure it was clear and not rusted out. There's nothing left (including my sanity)

 

Well you're getting the code 33, movement not detected. Code 34 is EVP above closed limit, which would mean it is sticking open.

 

Soooo.... since the valve is moving, are you agreeing that it must be something to do with the sensor? Or the relationship between the valve and sensor?

I just thought of something... I checked for voltage to the sensor. The solenoid is the part that would make the valve open, right? Could this be an issue with the wiring at the solenoid?

I'm really just frazzled and grasping at straws here!