The EGR valve will operate once engine is warm enough and under cruse/mid power level. At those settings the EVR will give only about 4 to 8 inches of vacuum to the EGR valve! At 8" vac, the EGR valve is almost fully open too.

If your wires are good from EVR and EVP to the ECU, then check for full engine vacuum to the EVR. If that is good, then one test I did, is use a 12V test light in place of the EVR . Drive the truck and once it's warmed up and crusing like 30 to 45 MPH, the test light should start to flicker. That means the ECU is trying to control the EVR solenoid.

Next step is here on my thread I did: https://www.ford-trucks.com/forums/1...d-evr-fix.html

 

.31 VDC is good for closed EGR value. Now you need to see if it increases with vacuum is applied.

I see someone else has suggestions to verify the EVR is being told to activate. I would verify the EVP output under static conditions as I previously outlined before going that direction.

 

Ah, found the 2nd thread finally ..... https://www.ford-trucks.com/forums/1...p-mileage.html

I knew there was another thread with more info.

 

it was a pain to get that .31 volts using a wire to back probe the EVP sensor using wire. I dont have any back probe pins and i do not have a vacuum gauge to apply vac to the egr valve why i do this to see if the voltage increases and i have to use 2 hands to hold my voltmeter to the evp sensor.

 

Use some pins from a sewing kit to pierce the wires. It's cheap and so am I.

You can take some time to diagnose the problem or start throwing money at it. It's your choice.

Reading between the lines here it appears you are convinced the PCM is bad. If you were simply looking for validation then I apologize for suggesting otherwise.

 

No I do not want to just throw money at it thats for sure I will get some from somewhere i just got tired of messing with it earlier plus It's not exactly warm in our neck of the woods but we're supposed to have another decent day down my way tomorrow. but i do wanna make sure it's something else or whatever before I have to buy a computer. thats cheaper.

 

Sorry rla2005 I am just aggrivated. I do want to try to diagnose it right I appreciate your, help I guess I did kinda want it to be the pcm because that would be the easy fix. But if I did put in a new computer and it ran the same, I would be even more mad, at myself for not listening to you guys about how to try to do it right. So i will get some pins pierce the wiring to see if the voltage increases. But I do not have a vacuum pump either you did say just use another vacuum source from the intake right? Again I apologise man I appreciate your help. Thanks Again!!! Robert

 

If you don't have a vacuum pump, the next best thing is get some longer vacuum line and hook it directly to the EGR valve. With engine off but key on, use the pins to go through the EGR sensor wires. Then pull a vacuum with your mouth(The old suck test!....insert joke here lol), and watch the voltage of the EGR sensor. The EGR valve will fully open with not much effort and EGR sensor voltage should increase. That's how I tested my EGR system.

Also you can verify the EGR valve function with the engine running, apply vacuum(ole suck test) and the engine should start to stumble more and more as you apply more vacuum to the valve. On my 89 F250 and 95 E350, I can stall the engines with EGR at idle. That test will show you the EGR passage ways are at least open enough and the EGR valve to function.

Now if you get no EGR sensor change with vacuum(EGR sensor change or engine stumble), it could be a bad EGR valve diaphragm ,one test for that is it will not hold the vacuum. Another possibility is the EGR pentle valve is stuck with crud causing it not to move(valve will hold vacuum).

The last thing I found with my 89 F250 was the EVR solenoid was a dead short, it should OHM out around 30 to 70 ohms, anything less than 30ohms or more than 100ohms means the EVR is bad.

The EVR solenoid is a venting type vacuum valve. When it is NOT grounded by the ECU it will vent the vacuum off the EGR valve. When the ECU does ground the EVR, it will apply vacuum to the EGR valve. It is also a duty cycle solenoid, that means it cannot handle full power for long period of time before failing!

 

Hey guys I just ran A KOEO test on my truck this time I got a code 84 EGR valve solenoid curcuit failure anyone kmow what this means the EVR is bad? please let me Know. Thanks Robert

 

DTC 84 indicates a failure in the EGR Vacuum Regulator (EVR) solenoid circuit.

Possible causes:

-- Damaged EVR solenoid

-- Open harness

-- Shorted harness

-- Damaged Powertrain Control Module (PCM)

l Key off.

l Disconnect EVR solenoid.

l Measure solenoid resistance.

l Is resistance within specification (20-70 ohms)? If not, replace it.

If it is within spec. then verify continuity of the wires.

 

Ok rla2005 I have good continuity to all the wire to EVP sensor, I know that. checked it again today. Checked voltage again to Evp sensor connector Had a good 4.97 VDC, Then I checked the volts with the connector on the EVP it was .410 VDC so that should be good. correct? Also I checked to make sure the voltage Increased as I applied vacuum to the EGR and it did that also, then I checked the OHMS to the EVR, it was 31.9 OHMS so that checked good there. Also there was A good 12 VDC to the red wire to the EVR, And there was good continuity, To the green wire from that. so what do you think? Thanks again for all your help. I appreciate it a bunch.

 

Assuming the wires are good leading back to the PCM from the EVR (and the EVP) I suggest you follow what was suggested in Post#16 Ford Truck Enthusiasts Forums - View Single Post - EVR problems again HELP!!!

Under static conditions everything appears to be good. Now you have to confirm the PCM is telling the EVR to turn on. It would be very rare to have a PCM exhibit this failure mode IMHO.

 

I am not sure how to hook up the test light to try this exactly to check that.

 

Also earlier today i had an old EVP that I put on the reason I replaced it in the first place was Because it had a code 32 so I replaced with the one that was currently, on the vehicle so i tried that one again on today and the code 32 came back with KOEO so this evening I changed them back disconnected the battery then tried KOEO and got code 84 and 52 Then did KOER and got codes 44 34 77 and 52 that doesn't make sense. Thanks again