33- Egr valve opening not detected.
Check engine light flashes on and off. This corresponds to small fluctuations in RPMs. Intermittent issue.

....does anybody have any experience cleaning or checking for egr function?

Any pictures on where to look for clogs...where to clean etc. would be helpful!

I could always go out and purchase a new unit, but I have a faint suspicion someone around here knows a fix.

Thanks in advance!

Mike

 

bumping this back to the top Mike....... so I can see the answers too.......

Bob

 

Bob-

Don't blame you in the least! It's a pricey apparatus.

Somebody here will have some experience clearing that up. Consider it bumped up to the top again.


Mike

 

Update:

Pulled Egr valve and position sensor. Cleaned both. Upon inspecting the diaphragm on the EGR valve, it appears to function properly. Carbon build up was not outrageous.

Egr position sensor appears to function...not sure if its reporting correctly.

Put it back together, cleared the CM codes, and the CEL came on 10 minutes into the test drive. KOER 33 again....

At $150 for the EGR valve and $45 for the position sensor, I'd like to not have to purchase both.

Any ideas?

Thanks
Mike

 

my 96 was doing that too it was the sensor. It sensece the vacuum before and after the egr inlet the stock on was alum the replacement was all plastic but has lifetime warenty. Note: parts stores called it by 4 diffrent names!

 

Just to clarify, it was the position sensor and not the egr valve itself, correct?

 

The EGR is controlled by vacuum. The amount of vacuum is controlled by the computer from data it receives from the sensor mounted above the EGR. The computer controls the EGR vacuum with a little device on the drivers side of the engine towards the back just above the fuel rail. You will see three little relay looking devices there, the EGR Vacuum Control is the one in front ( usually a round one that is mounted to the bracket that houses and mounts the rear two) . That is probably where your problem is. Check it's connector for corrosion. There is a green vacuum line that goes from it around the back of the intake plentum, then to your EGR valve.

With the engine warmed up, there should be a vacuum on this green line at the EGR when the engine is revved up. There should be no vacuum at idle, or when the engine is cold.

 

I followed that green line to the drivers side of the motor, next to the fuel rail. Am I checking the connector, where the green EGR vacuum line connects there? Or something else on the bracket? There are two lines attached to this area as well. Looked fine, when I removed the two....

 

I, am assuming that you have a bored out 302 5.0 EFI.

If so, the most forward of the three vacuum controllers you see there has a black and a green vac line. the black is the input and the green is the output to the EGR.
It also has an electrical connection to the computer. This often gets corroded connections on the connector pins. They get a greenish or whiteish corrosion.

 

That is correct. 4.032" bore

I found that. Removed the vacuum inputs, and saw nothing that stood out.

And these are located where? Behind the bracket where the vacuum lines terminate?

Just trying to clarify!

And thanks for your prompt responses thus far.

Mike

 

The connector plugs into the unit with the green and black vac lines.

If you disconnect the green and black vac lines from the unit, you can then remove the unit with two nuts that secure it to the side of the bracket that houses the other two control units.

Then it may be easier to remove the electrical connector and clean contacts.

 

Chances are the EGR Vaccuum Solenoid went bad, which is that thing everyone's talking about with an input and output of vaccuum lines, and an electrical connector. I've seen a few go bad. If I remember right, they run about 50 bucks or more. I remember it was too expensive for me to not go to a junkyard!

Either that, or the EGR valve position sensor went bad. You can test this. Give this thread a little bit and subford will chime in with exact information... but I'll tell you what I know.

The sensor has 3 wires going to it. A feed of usually 5V, a ground, and an output. When the sensor is closed, the output side should read a low voltage (maybe around 1 volt, if that.) As the EGR opens, it pushes that rod on the sensor, in which case the voltage numbers on the output wire should slowly rise. You can pull the position sensor, and just poke around on the wires with a multimeter with the key on to see what you can find. Just cross two together until you find the 5 volts, and then alternate one to the other. If you get around 1 volt, then the one you just probed is the output. If you get 0 on the other, keep searching.

 

Update-

Checked the Egr Vacuum solenoid. Contacts looked great, no corrosion.

Installed new EGR position sensor. Test drove and CEL came on shortly after startup.

I'm gonnna try finding another Vacuum solenoid in town next....

Unless I hear something from someone well versed with this code shortly.

Mike

 

The PCM likes to see about .6 volt at the EVP output when the EGR is closed.

 

Thanks for clearing that up netscanner. I wasn't sure exactly how much voltage it was putting out when it was closed. I know the TPS puts out about .08V at closed throttle and about 5V at WOT.