Heres a picture, a crappy one, so i can understand better.

The Yellow looking piece at the top with the harness is the EVP right?

Under it, is the EGR Valve?

And the EGR nipple(non-visible in this picture) would be on the other side with a skinny pipe going to it.

And brokenwire as for the pipe, i tried, and i mean tried, to take it off but it wont budge!

Some other things were mentioned in this post. The diaphragm and the pintle valve. Where would these 2 be located?

 

I can't see the picture but what you described sounds correct.

The diaphragm and the pintle valve are both parts of the EGR valve itself. The diaphragm is in the fat portion of the EGR valve and can probably be seen through the holes around the bottom of it, and the pintle valve is driven by the diaphragm and can be seen from the bottom fitting where the exhaust tubing attaches.

 

Ok....I can't seem to edit my posts....

Anyways...
#1. Would be the EGR nipple (non-visible in this picture). Behind on the other side.

#2.EVP

#3.EGR Valve

#4.The Pipe.(that I can't seem to remove to check for leak.)

Thanks gates for explaining diaphragm and pintle valve.
Also, someone mentioned carbon build-up in the seat area, where would this be located?

Thanls for being patient all

 

#1 should be the connection from the output of the EGR valve to the intake plenum.
#2 is indeed the EVP
#3 is the portion of the EGR valve containing the diaphragm
#4 is the pipe supplying exhaust gas to the EGR valve.

The seat area is about halfway in between your number 3 and number 4. The pintle is just a rod actuated by the diaphragm, the end of which rests on the seat when the valve is closed. The seating area is quite close to the point at which pipe #4 connects to the EGR valve proper. You have to get that pipe off the bottom of the valve to clean it or change it.

 

EGR solenoid needs to vent vacuum for the EGR to close.

Did you get your problem fixed?

 

Bump, was the problem fixed?

 

Sorry, still working on it. With school and work, I have been VERY busy. I haven't driven the truck in like a week. I'll see what i can find tomorrow after school. I also gotta replace my U-joints. Does everybody's Ford have 3 u-joints?

 

All F-150 supercabs appear to, I know both my '91 4x2 8' box supercab and my '95 4x4 8' box supercab do, along with a slip joint and carrier bearing. I can't say 100% for supercab short box trucks. I am fairly sure regular cab with both long and short box are just one driveshaft with two joints. Take a real good look at that carrier bearing.

 

Bump..

Sorry for not posting sooner. Anyway, I have replaced the EVP. I reset computer and took it for a test drive and sure enough, CEL came on. I pulled codes but it seems that my 34 and 41 are gone. I now get a 33, EGR Valve Opening Not Detected. What does this mean?

I also stuck a flathead screwdriver in the EGR and lifted up and my engine stalled. That means it works, right? Also, I took off the Vacuum line going to the EGR while the engine was running and I didnt notice a difference in idling.

What to do next??

---
Off topic U-Joint question.
I get a clunk in reverse and terrible shudder around ~30mph. They're bad right? Also, i hear a loud squeaky noise while Driving, but if I shift into neutral the squeaky noise stops. Is this related to U-joints?

 

Code 33 means the PCM asked the EGR valve to open, and didn't get confirmatory feedback from the EVP sensor. When vacuum is supplied to the diaphragm, the EGR valve pintle should move upward, which in turn should push up on the EVP, which in turn should change the voltage going to the PCM. The PCM is not seeing this voltage change and so it sets code 33.

There are several possible reasons:
1) The vacuum diaphragm in the EGR valve leaks
2) The vacuum tubing between the manifold, the control solenoids, and the EGR valve is broken or leaks
3) The control solenoids and their valves are not working to supply vacuuum
4) The control solenoid wiring is bad
5) The EVP sensor is bad, or there is a problem with the wiring to it.

There are supposedly two kinds of EVP sensors, a gray one and a black one. They are not interchangeable. Did you put in the correct one?

Your screwdriver test proves that the EGR pintle is not stuck, the exhaust gas delivery ports are not blocked, and the spring that forces the valve closed in the absence of applied vacuum appears to work. But other than that, it doesn't do much to diagnose code 33.

Pulling the vacuum line off the EGR valve at idle should not have any effect (as was the case for you). The PCM does not engage the solenoid to supply this vacuum at idle speed. This particular test is not helpful.

Test the EGR valve diaphragm for a possible leak. The best way is with a Mity-Vac pump and a guage. But if you don't want to buy test equipment, there is the cheapskate way. Connect a clean vacuum hose to the valve and suck on it by mouth, as if drinking a thick milkshake from a straw. You should feel a strong opposing suction, and should be able to move the pintle off the seat by sucking hard enough. Plug the tube with your tongue and see if the EGR valve holds vacuum. It should hold your tongue stuck to the hose for long periods. Don't let your wife, buddy, etc see you doing this or you will not live down the razzing. But this method works well if you don't have the vacuum pump and guage.

If air just whooshes through the hose when you suck on it, the EGR valve leaks and needs to be replaced.

One thing you can do to test the sensor and wiring is to remove the screws securing the EVP. Pull the EVP out of the EGR valve. Push the EVP plunger all the way in, and tape it in place. Leave it connected to the harness. Run a KOEO test. (Don't start the engine). You should now get code 34. If you don't, the wiring or EVP sensor is bad.

Put everything back, clear the PCM, and run a KOER test. Does code 33 happen during the KOER test? If it does, you have a solid failure and can diagnose it. If it doesn't, you have an intermittant failure and will have to hunt for dirty connections, etc.

If code 33 happens on each KOER cycle, connect a vacuum guage to the line going to the EGR valve, and watch what happens during the test. Does the guage twitch or not? At some point in the test the PCM will advance the RPM above idle, and try to operate the EGR valve. You want to see if vacuum ever appears at the valve. It should during the test, but not at idle or when the engine is cold.

 

Oooh, nice big reply .

So the EVP i got is indeed BLACK. It looks exactly like the gray one so I figured it was just the color difference. Apparently, Advance Auto doesnt take returns if you installed the product. Makes it kinda hard to see if it worked, eh?
Quick Question: When testing the EGR diaphragm for leak, engine is on/off?

I'll post back answers tomorrow.

 

You can test the integrity of the EGR diaphragm with the engine running or not. You are just trying to find out if it holds vacuum. If you use the "suck on a hose" method, probably best to have the engine off. If you have a vacuum pump, you can repeat your screwdriver experiment, this time by applying vacuum with the engine running.

 

A vacuum pump is an essential test tool and is cheap, $24 or so dollars at Autozone or similar store. I bought a plastic Mityvac several years ago and would not be without one. You can also use it as a vacuum guage to test the engine vacuum.

 

Ok...This what happened.

I did KOEO test with EVP taped down and got a 34.
KOEO with no tape on EVP and got code 31.
EVP in its normal position gave me KOEO 11 (system pass). Seems like EVP is functioning properly.

Now, when trying to do KOER test, all I got was 4 flashes and nothing after that ??

 

It appears that your EVP and wiring are OK. There is still some question about the resistance of the sensor (gray vs. black), but it seems to be capable of registering "too far closed", "just right", and too far open". As for code 32, we are still left with the vacuum diaphragm, the vacuum hoses, the control solenoid, and the control solenoid wiring as possible culprits.

As for the KOER test:

The KOER test takes a while (about 1 to 2 minutes) and it relies on correct input from you in two different places.

Here's how to run it:
1) Warm the engine up thoroughly. The temperature guage should be above the "thermostat open" point. Shut off the AC/Heat. Turn the engine off.

2) Install the STI jumper and turn the key to on, thereby running a KOEO test. Wait for any codes or "system pass" to appear. Wait 30 seconds more.

3) Start the engine. After about 10 seconds, 4 flashes should appear.

4) Immediately after the flashes, step on the brake, turn the steering wheel, and push "O/D cancel" a couple times (if applicable), or press clutch pedal to the floor (if applicable)

5) The engine running test will proceed. Engine RPMs will shift up and down as the PCM tries out the various sensors. After about 45 seconds to one minute, there will be a single flash of the check engine light.This is your cue to stop the gas pedal (it's called the "goose test"). The stomping enables the PCM to test the TPS, the knock sensor, and the extended range of the MAP sensor.

6) Any codes, or the "pass code" will be produced 5 to 10 seconds later. Write the codes down and shut the engine off.