89 E350 with a 460

I ran KOEO with no faults, but KOER give me a code 33 (EGR valve not opening)(Yes, I did a WOT during the KOER test).

First I checked the EGR Valve. Hooked a vacuum pump directly to the EGR and it opened.

I then checked the vacuum on the input to the EVR and it is 20inHg. The output is ZERO. (Most of the time that's OK.)

However, during WOT, or with the engine under load, the EVR output vacuum remains at ZERO. Well, I did get about 5in.Hg at one time but the valve didn't physically open.(I can see the shaft on the EGR valve.)

I pulled the filter off the bottom of the EVR and plugged the hole with my finger. I got plenty of vacuum on the EVR output when I did that. Now I just wish I knew what it all means means.

So, how do you check the EVR? For instance, what should the output vacuum to the EGR read and under what conditions, and what is the electrical input signal to the EVR under what conditions.

 

Just in case anyone else ever needs this info.

The EGR Vacuum Regulator (EVR) controls the opening and closing of the EGR valve. The EVR is an electromagnetic solenoid and should have between 20-70 ohms resistance between the pins. +12volts should be constant on one side from the EEC Relay, the computer controls the ground signal when EGR flow is needed.
When the EGR Vacuum Regulator (EVR) is off, both ports vent slowly to atmosphere.
To test it mechanically check to see if vacuum is present at the EGR valve with the electrical connector unplugged from the EVR. The top port should not have vacuum! Because that would open the EGR at the wrong times.
With everything connected and the engine running at operating temperature ground out the pin 33 side. The EGR valve should open and the engine RPM should change.Ford EGR valves will open 50% at 4 in.Hg of vacuum, and 100% at 8 in.Hg of vacuum.

 

I just went out to the old beast and checked the voltage at the EVR connector. +12v on both sides of the connector. I then grounded the pin 33 side and the EGR opened and the engine idled rough.

So, the EVR/EGR is working as expected. Now all I have to do is make sure the ground is getting to the pin on the EVR from the computer. I should see a voltage drop on that pin when the engine needs EGR.

I'm still trying to figure out exactly when the EGR should open and how the computer knows to open it - I'll figure it out sooner or later but if someone would like to tell me it would be greatly appreciated.