I thought you checked the solenoid for function. If it's not energizing it won't allow movement of the EGR.

 

Well, I checked vacuum in and out, and I checked for movement based on increasing throttle while engine was warm. Both checked out fine. I didn't check for voltage (or intermittent voltage for sure) because it seemed to be working right.

Do you know what I'm looking for if I check voltage across the 2 leads on the solenoid plug? I would assume it's variable depending on demand? Would/should the voltage be low or zero (1/2 volt or less maybe?) with key on engine off? I don't have any info in the chilton book about this, and that's about the only source of info I have ...aside from you!

 

The EVR solenoid is provided continuous voltage in the RUN position, the PCM completes the circuit on ground side by alternately grounding and opening circuit.

According to the wiring diagram, the solenoid gets 12v all the time in the RUN position, so check for varying ground with the engine warm and running with varying amounts of throttle. The computer gives a very fast ground pulse, so it may be difficult.

No test procedures listed for the electrical side of the solenoid, just for solenoid function, so this is the best way I figure to test it.

 

Man... it was just a few hours ago that I was gonna put this aside for awhile and let my brain rest. But, I've been scouring the net and your brain too in my continued quest for a fix.

I've found several sites with detailed testing info through the entire egr sytem - most of them relate code 33 with the evp sensor not closing. I hadn't seen this code definition before, but that just might support my theory that the damned thing isn't fitting on the valve right. It has to retract a good 1/16" or so to seat. The truck has run better, with less violent symptoms since adding a 2nd gasket to try and remedy this.

I feel like I might be on to something - but I've felt that way before...

I'll see how it runs on the way to and from work tomorrow, and go from there. With the additional gasket, it should be closer to the right fit, but can't tell exactly where it's at.

If results are good, maybe I'll try this - I still have the old EVP sensor, which just might be good. I might try to file down the pintle on the old sensor, until it just barely meets when seated on the valve, and see what happens. If that turns out to be all there was to it, I'll crap myself.

 

Well my code book says 32- EVP voltage too low, 33- EGR movement not detected, 34- EVP voltage too high. 34 should be the EVP not closing, but hey, might as well try something new. You should probably try the old EVP sensor first before you destroy it.

 

The fact that you include the phrase "before you destroy it" tells me that you have a lot of faith in my abilities!

I'm just on information overload again... Looking over the info on the 'net, there are so many conflicting definitions that my head is spinning.

I'm gonna get some sleep, try to clear my head, think this through while I'm supposed to be at work, and maybe I'll destroy something tomorrow evening!

 

Well, with the 2nd gasket on, the truck drove a lot better. Still not quite right, but much better.

Alright... I've been out in the driveway tinkering with this idea. Using the old sensor (which might be good anyway), I set it on the valve to get an idea of how much room I had between contact with the pintle, and the sensor actually being seated. Considering both gaskets, there was still some room.

Using the benchtop sander, I shaved off about the same amount and mounted the sensor just tight enough to get vacuum. I didn't get the 33 anymore, but I got 327 and 328 codes as I made minute adjustments to the mounting screws on the sensor. Once tightened down too far, the 33 comes back. With a tester on the output, I should be able to get it in range, because I'm right there close.

Maybe if I can get it just right, I'll see if the old sensor really works or not, or if it won't hit the right spot, I might have to shorten the new sensor to match and try that one.

 

I've been tinkering with this thing most of the evening, think I have it about right, and took it for a long drive. Had a slight chug until up to temp, then it smoothed out pretty nice. In fact, it stayed nice and smooth for an extended period of driving - no stalling at stop lights, no shaking and chugging, etc.

In the midst of studying the chilton book, studying everything I could find on the web, and staring into the engine bay of my truck for hours on end, I noticed something odd.

The throttle position sensor - chilton says it should mount with the pigtail pointing toward the IAC. Mine is just the opposite. Not getting a code for it though... Could that be causing some of my issues, or is it ok mounted either way?

If I take the upper intake off to get under the valve covers per my other thread about valve noise, I could switch that sensor while it's apart - the tps has some bare wire showing on the pigtail, which I've wrapped, but would rather not leave forever.

 

I can't see where the IAC is in the pictures in my book, but the connector is facing the passenger side on the TPS. The text reads "To install the sensor, position it with the wiring harness (or connector side on models without a pigtail) pointing away from the IAC".

 

Well, that's that... I think I've been studying that chilton manual for so long that I can't see straight anymore!

Thanks for the wake-up!