'92 F150 5.0L

My understanding of the EVR:

The EVR controls the position of the EGR via delivery of vacuum.

The EVR will deliver vacuum to the EGR when energized. When not energized it does not. Based upon input from the EVP (EGR position sensor) the computer will turn on and off the EVR. The EGR should remain closed until engine is at temp and at load.

In diagnosing vacuum leaks starting at the intake manifold. I pulled a vacuum with a hand pump down each line. The line going to the EVR will not hold a vacuum.

Should the EVR hold a vacuum when not energized?

I assume it should until energized, at that point it passes vacuum to the EGR. It should at no point just suck air.

All this to just to say that my EVR is sucking and it is a dealer only item. Am I correct in my assumptions and I need a new EVR?

Thanks,
Craig

 

On my 89 302 van, the EVR is not supposed to hald a vacuum. It passes air all the time and modulates the amount of vacuum that goes to the EGR valve. It even has a filter in it because air goes to the intake through it at all times. So if yours is of a similar design, it may be ok.
Make sure it is not applying vacuum to the EGR valve at idle and see if it does apply vacuum when you raise rpm to 2000 or so. If it does that, it's probably ok.
Hope this helps.

 

The Exhaust Valve Regulator should vent the EGR side when it's de-energized, but hold vacuum to the intake side. The filter is to keep the EGR diaphragm from collecting dust.

 

So, Steve, is it a duty cycle system instead of a modulating system?

 

From the Ford service manual:

1. Run engine until normal operating temperature is reached.

2. With engine running at idle, disconnect EGR vacuum supply at the EGR valve and check for a vacuum signal.

NOTE:
The EVR solenoid has a constant internal leak. You may notice a small vacuum signal. This signal should be less than 3.4 kPa (1.0 in-Hg) at idle.

3. Is EGR vacuum signal less than 3.4 kPa (1.0 in-Hg) at idle?

If not, then INSPECT EVR solenoid for leakage.

And yes, it is a duty cycle component. From the manual:

The EGR Electronic Vacuum Regulator (EVR) solenoid is an electromagnetic device which controls vacuum output to the EGR valve. An electric current in the coil induces a magnetic field in the armature which pulls on a disk closing the vent to atmosphere. The Powertrain Control Module (PCM) outputs a duty cycle to the EVR which regulates the vacuum level to the EGR valve. As the duty cycle is increased, so is the vacuum signal to the EGR valve. The vacuum source is manifold vacuum.

 

I had never noticed that there was a constant small leak. This is what Haynes says:

Electronic fuel injected systems operation and checks

EVR Solenoid Valve Operational Checks
47 Vehicles with EFI use only one solenoid valve to control vacuum to the EGR valve, the Exhaust Valve Regulator (EVR) (see illustration). In operation, the EVR is supplied a continuous source of manifold vacuum at its inlet port. When directed (energized) by the PCM, it will open from its normal closed position and allow vacuum to the EGR valve. When the EGR valve opens to the proper position (EVP sensor indicates position to PCM), the PCM will turn the EVR off and the solenoid closes. Vacuum between the EGR valve and the EVR solenoid valve now vents through the EVR valve, allowing the EGR valve to move to a more closed position. To maintain the EGR in desired (Hold) position, the PCM must again direct (energize) the EVR to open, and the cycle continuously repeats. To change EGR valve position, the PCM simply holds the EVR open longer (opens EGR further) or closed longer (closes EGR valve further). This duty cycle occurs continuously, maintaining the EGR valve at the desired position. The EVR solenoid is provided continuous voltage in RUN position, the PCM completes the circuit on ground side by alternately grounding and opening circuit. Caution: A small leakage during valve closed tests is considered acceptable.

48 The conditions for testing are as follows:
Engine not running, key off, EVR electric connector disconnected.

49 Remove the vacuum supply line from the EVR solenoid. Install a vacuum gauge to the EVR outlet port and using a hand-held vacuum pump, apply vacuum to the manifold vacuum supply inlet port. Vacuum should hold and no vacuum should be indicated at the gauge. If not, replace valve.

50 Install ground jumper to one EVR solenoid terminal and a 12-volt source jumper to the other to open valve. Release trapped vacuum if required and repeat the vacuum pump test. Vacuum should now be indicated on the gauge and vacuum should hold. If not, replace the valve set. Caution: Do not leave the hot (battery) jumper installed any longer than necessary.

51 Remove the jumpers to close the valve and connect the vacuum pump to the EVR outlet port. Apply vacuum to the port to test venting. Vacuum should bleed. If not, replace the valve.

52 Measure the resistance of the solenoid valve at its electrical terminals. Resistance should be between 20 to 70 ohms except for the 7.5L engine, which should be between 100 to 135 ohms. If not, replace the valve.

53 If all checks pass, the EVR solenoid valve is operational - proceed to the circuit checks.

EVR circuit checks

65 Disconnect the EVR electrical connector.

66 With ignition switch in RUN position, check for voltage at B+ (VPWR) terminal on the EVR electrical connector (see illustration). Greater than 10.5 volts should be indicated. If not, proceed to Chapter 4 Section 15 and perform the EEC power relay checks to obtain voltage.

67 Disconnect the EEC PCM electrical connector (see Chapter 4 Section 16 if necessary). 68 Check the resistance between the EVR electrical connector signal return pin and PCM electrical connector pin 33 (see illustration 5.57). Resistance should be less than 5 ohms. If not, service the circuit for open.

69 Check the resistance between the EVR electrical connector signal return pin and around (PCM still disconnected). Resistance
should be greater than 10,000 ohms in both cases. If not, service the circuit for a short to ground.

70 Check for stray voltage at the EVR signal return pin (PCM still disconnected). No voltage should be indicated. If it is, service the circuit for a short to power.

As you look into the harness connector for the EVR with the lock tab on top, the L terminal is hot from the EEC Pwr relay (and goes to almost every other sensor & actuator), and the R goes directly to pin 33 on the EEC.

 

" ... Install a vacuum gauge to the EVR outlet port and using a hand-held vacuum pump, apply vacuum to the manifold vacuum supply inlet port. Vacuum should hold and no vacuum should be indicated at the gauge. If not, replace valve. ..."

So I get to buy a new one.

Where other than the dealership can I order this part. All the local auto part stores don't have it or can't even order it.

 

You could try:

http://www.fordpartsonline.com/

 

I replaced mine a lil' less than a year ago. Got it from the dealership for about $26, cuz like you said, no one else carried it.

 

I think the Haynes is not very clear on this. The only way that the above will occur (Install a vacuum gauge to the EVR outlet port and using a hand-held vacuum pump, apply vacuum to the manifold vacuum supply inlet port. Vacuum should hold and no vacuum should be indicated at the gauge), is if you remove the sponge air filter on top of the valve and plug the line.

The question at hand is how tight of a seal does that sponge air filter need to create? Mine will not hold a vacuum and I can only make the Haynes diagnostics happen if I remove the sponge air filter on top of the valve and plug the line.

Comments?

 

billman
Yours is leaking. Reread section 47. The sponge filter is only there to allow the EGR to leak down when the EVR is de-energized. Your "small leakage during valve closed tests" is a little too much. You might be able to reduce it by removing the valve & tapping it to free up the solenoid at the bottom of its travel & reseat the pintle.

 

O.K. So the big question is, what are the effects at idle and driving performance (hesitation, gas mileage...) if the EVR is leaking?

 

Same as any other small vacuum leak. I'm not saying that valve is the source of any particular symptom you've observed: just that there's a reason it's not passing the test. It's defective, but not necessarily significantly.

 

Evaluating the EVR solenoid valve from the Ford Service manual takes a differrent approach than the Haynes. It seems as if their concern is that when the solenoid is not activated, there is no flow through the EGR port of the valve and when activated, there is flow through the EGR port to the manifold vacuum port.

I just don't want to go on a goose chase. Like most others, I prefer not to throw parts at a problem.


The manual:

1. Disconnect the vacuum hoses.

2. Blow into the EGR valve (EGR valve) (9D475) and verify that air does not flow.

3. Disconnect the EGR valve electrical connector.

4. Apply battery voltage and a ground to the EGR vacuum regulator control (9J459) as shown.

5. Blow through the EGR vacuum regulator control and verify that air flows.

6. If not as specified, replace the EGR vacuum regulator control.

 

Billman has the same testing symptom that I do, EVR not holding a vacuum when a hand pump is applied to the manifold side.

Anyone else willing to go out their driveway, pop the hood, and perform this test on theirs?

Seems to me that if the EVR just sucks air that it creates a huge vacuum leak. The line to the EVR also goes to other stuff....