I'm using an Innova brand code reader that is giving me 2 codes in the second group of testing.

The first code is

327 - EGR valve position circuit below minimum voltage

There is another description for the same code that points to.

327 - EVP/EPT circuit below minimum voltage

The other code is

328 - EGR closed valve voltage lower than expected

I have done some research about the EGR system and how it works, but I don't have a full understanding of it yet. The guy at the Ford shop said there was an issue with the sensor for the year of the vehicle and recommended I not use the after market part for this specific EGR Valve Position sensor.

The van starts and idles fine, the hesitation is happening when it's warmed up and accelerating from a complete stop or driving below 30 mph. It runs fine and drives fine when it's cold. I would just like to ask a couple questions before I go replacing unnecessary parts.

Does anyone know where the EGR Valve is on a 92 E350 5.8L? I'm looking from the front passenger side under the transmission dipstick, is that where the EGR Valve to my left of the throttle body?

I also have a tank filler hose that has a hole in it...I will be replacing that also, but I'm wondering if that can have an effect on performance like this?

If this issue was related to the coil would there be an error code for the coil and/or other sensors in the system?

Last question, it looks like whoever had the van before me removed the catalytic converter will that cause a performance issue?

I just took the engine cover off and warmed it up...when I turned it off it was making all kinds of strange noises like clicking. I am going to have someone else listen to it so I can figure out how best to describe it. I will update this as soon as I can get a better description of the sounds.

Thanks in advance.

The sound is like a light chattering like something is winding down. I had someone listen and point out where they think it could be coming from and she says around the ignition coil. I think it sounds like it's coming from something that looks like a fuel regulator kinda behind where the coil is. it has a braided hose and a single red wire connected to the top. I haven't been able to trace where that wire goes yet.

 

Both of those codes point to a bad EGR valve position sensor which is located right on top of the valve which is just to the passenger side of the throttlebody as you suspected. I would agree with the Ford tech about the aftermarket sensors too, I routinely use unknown milage junkyard Ford sensors instead of brand new aftermarket sensors because these new parts are so unreliable.

Tank filler tube won't affect engine operation but there are codes for all the other sensors and you could expect something to show up for them if there was a problem.

This vintage truck doesn't have a downstream O2 sensor so the computer wouldn't know the cat exists even if it was there.

 

Thanks for the reply Conanski.
It sounds like everyone I've talked to says the sensor too....any idea on the lifespan of those sensors as a temporary fix until I can afford $108 for the Ford part?

 

Aftermarket sensors can last years but some only last days, I think you will be relatively safe with an aftermarket version of this particular sensor however as it's a very simple device.

 

Thanks again Conanski.
One more question...I'm suspecting those sounds i'm hearing when turning off the engine, with the engine cover off, is the fuel pressure regulator. I'm about to research this some more, but I'm wondering if it's normal for it to make strange sounds like it's winding down and clattering. The clattering sound may not be a good description of the sound...maybe it's more like a steady ticking coming near the valve covers. I don't think it has anything to do with the valves though. Could the fuel rail and injectors be the cause of the noise?

 

Here are some simple checks of the fuel pressure regulator:

Pull the vacuum line on the regulator to see if there's any fuel in it. If so, the regulator diaphragm is leaking, and it needs to be replaced.

Otherwise, make sure there's no fuel around or beneath the regulator (although you would smell those first). There are a couple of O-rings that seal the regulator to the fuel rail that can leak with age.

 

Thanks for the input xltwd90. I haven't started digging into this project yet, kinda waiting til this weekend and doing some more research.

I've been reading another forum post for a 96 Ford Explorer where someone explains that the position sensor reports the position of the EGR valve which is vacuum controlled by the EGR vacuum regulator. The vacuum regulator is controlled by the PCM via an electrical solenoid. If the regulator isn't working correctly then the sensor will report what appears to be an incorrect value.

I plan on testing all of these systems this weekend, but now that I found that information about the EGR vacuum regulator solenoid I'm wondering if that could cause a lower than expected voltage reading on the EGR Valve Position sensor. The issue for that Explorer was related to EGR valve excessive flow. The guy with the Explorer replaced the sensor but it didn't clear the code he was getting. Unfortunately he never posted whether the issue was fixed or not.

It seems like a lot of people are replacing the EGR Valve sensor without it resolving their issue and I would like to avoid replacing something that doesn't need to be replaced...who wouldn't huh. I've suspected the symptoms are more fuel related from the beginning because someone had tried to steal gas from it when the previous owner had it. The filler neck was tore apart and the flap was missing where the nozzle goes in, the filler hoses were leaking and the guy had the wrong fuel filter on it.

Could a fuel issue cause problems with the EGR system like this?

 

No, I do not believe a fuel system problem will cause the EVP error message.

There is actually a pair of solenoids that the PCM uses to regulate the vacuum to the EGR valve; one is a source that applies vacuum when energized, and the other is a dump that vents the vacuum when energized (to deactivate the valve). I've never seen those go bad before, though anything is possible.

The EVP sensor, being an electronic device that sits right on top of a valve that controls very hot gasses, tends to fail more often. It's just a potentiometer that is moved by a little pin on the diaphragm of the valve. You can pull it off and test it with an ohm meter for smooth operation, or dead spots.

A very common failure is that the EGR valve gets stuck in some position due to crud build up. This can cause it to not close completely which can cause idling problems, and can cause the PCM to register an error code. You can try pulling it off the intake manifold and cleaning it; pull the valve open with a vacuum pump and scrape the crud off the opening. You will probably destroy its gasket in the process, so you need to find a replacement.

 

Thanks for the reply xltwd90. I will pull the egr valve out to check everything. It's kinda looking like it would be easier to pull the whole thing rather than just the sensor anyways.

Hopefully this solves the error code so i can proceed to the next level of code scanning if it doesn't resolve the symptoms.

UPDATE

So, while I was checking the fuel pressure regulator, I noticed there was a spot that
looked damp with some dry dust in areas under where the intake gasket is. When I barely
touched a part of gasket sticking out, it about crumbled. I compiled and compared some
troubleshooting tables for the issues I'm having and the most common issues relate
mostly to air and vaccuum. I still only have the error code 327 and 328.


EGR Valve not functioning properly
HESITATION
SURGING (at cruising top speeds)

Improper feedback system (Emissions)
FAULTY ACCELERATION
HESITATION
SURGING (at cruising top speeds)
POWER NOT UP TO NORMAL
FAULTY LOW-SPEED OPERATION
FAULTY HIGH-SPEED OPERATION

Air leak in manifold vacuum
HESITATION
SURGING (at cruising top speeds)
FAULTY HIGH-SPEED OPERATION

Restricted air cleaner
FAULTY HIGH-SPEED OPERATION

Restricted idle air vents & passages
FAULTY LOW-SPEED OPERATION


Air leak in vacuum hose connections
HESITATION

Throttle body leaking
HESITATION


The problem started as a minor hesitation when accelerating from a complete stop when it
was warmed up. I quit driving it van as much since the problem started...mostly just to
the store every once in a while. As the hesitation got worse, it started to display
minor surging similar to the early stages of the hesitation. Now the surging is at the
point where I need to do something about it while I have the time.

I was figuring it was a fuel problem because of the issues with the filler neck and
hoses when I bought it, but as I began researching this it was seeming more like an air
or vacuum issue and the code sort of confirmed that with an EGR system issue. The only
problem with that was the code being related to the EGR sensor and voltage. I'm stil
going to take out the EGR valve and test it and the sensor and connections. I'm thinking
it's possible a lot of the gaskets need to be replaced so I'm going to be getting a Head
Set to do the whole top of the engine. It's going to be the perfect opportunity to clean
up and check everything that's hard to get to under the hood so that's cool.

As far as I can tell, this manifold leak may be causing the EGR vacuum solenoid to not
open the EGR valve enough when warmed up because it doesn't have the correct vacuum
pressure. So if the valve isn't opening within specs, it could be causing the EGR
position sensor to give something like a false reading. I'm not so sure it could be
called a "false" reading though, because wouldn't a lower than normal voltage indicate
that the position of the EGR valve is lower than it should be? And if the reason the EGR
valve is lower than it should be is because there's not enough vacuum pressure to open
the EGR valve to where it should be, then the sensor could still be good? I noticed some
hoses near the vacuum pump that could be leaking too, so I'll be replacing those. I'm
thinking that even though the code is pointing to a faulty EGR position sensor, there's
a chance the problem isn't because of the sensor itself.

Am I off base on this reasoning?
Does anyone who has done this job on a 5.8L e350 have any tips?
I'm still researching if there's any tools I don't have. I mostly just have the basics.