p0402 Where is EGR

JIMBOBX4 · #1 05-16-2005, 12:43 PM

I have received the above code immediately after a repair shop fixed my CPS code (new camshaft position sensor and synchronizer).
Could this be related to this work?

More importantly, I want to fix this code. Haynes says to apply vaccum to the EGR to see if it is working but I cannot locate the ERG.
This is a 99 v6 3.0 liter engine.
I am afraid it is on the firewall side of the engine which is not accessible to someone of my limited skills.
Anybody have any insight into the EGR on this engine and how to access it?
Thanks

wiswind · #2 05-16-2005, 10:01 PM

I tried to look on the Autozone website....under repair guides...but they do not list the '99 windstar.
I looked up the '96 3.0L and the EGR valve is located under the throttle body. The DPFE sensor is located kinda right over the EGR valve.
The DPFE is MUCH higher failure as far as items failing.....however.....as you had work done.....I would check to make sure that there is not a vaccum line that has been bumped loose.

Using my '96 3.8L as a reference point....the EGR valve is opened by a vaccum....which comes into the top of the EGR valve through a hose. That hose goes to the EGR Vaccum Modulator Solonoid.
The EGR Vaccum Solonoid has an electrical connection.....and 2 vaccum lines. One vaccum line is the one that goes to the EGR valve....and the other is a constant (as long as the engine is running) source of vaccum. On my engine....that source.....ultimately....through a few "T" connections......is from the PCV line.

The Electrical connection on the EGR vaccum Solonoid.....ends up going to the PCM. The PCM gets a signal from the DPFE as to how much EGR flow there is.....and sends the signal to open / close the EGR valve. The EGR valve is not a high failure item....but as I mentioned....a problem in the vaccum connections is possible.
There is a pipe that goes from the EGR valve.....to one of the exhaust manifolds. This is where the exhaust flows from the exhaust manifold.....through the EGR valve....into the intake manifold.....

The DPFE has 2 hoses that go to the EGR Pipe. There is a slight restriction in the EGR pipe in between the the 2 hose connections....so when there is flow through the EGR pipe.....there will be a pressure drop between the 2 hoses....which will be an indication of how much flow there is in the pipe. The DPFE sensor....senses the difference in pressure....and converts that into an electrical signal...that goes to the PCM....and so on.

Sitting at idle....there should be NO EGR flow.
If you were to apply a vaccum to the EGR valve.....with the engine at idle.....it should start to run rough.....If it does NOT.....then there is a problem. I am not sure if the 3.0L has multiple EGR ports......or if it only has 1 port.... On the 3.8L....which has a port for each cylinder....the EGR ports often become clogged.

Sorry for the lengthly discussion.
I find it easier to solve a problem when I understand how the system works. Most of the windstars have the 3.8L engine......

You may find the autozone website helpful....even if you do have to look at 98 and before.....they have pictures and drawings showing where things are....and what they look like......

JIMBOBX4 · #3 05-25-2005, 08:00 AM

Thanks for the help. The Autozone site was helpful anyway since I found a similar engine. The EGR appears to be under the throttle body? (aluminum structure on top of engine). Is that difficult to remove and reinstall without special tools, gaskets, etc.?
Thanks again for taking the time to post.

12Ounce · #4 05-25-2005, 10:15 AM

In the Haynes chapter 4 ..."Fuel and exhaust systems" ... does yours have photo 13.8? It shows the top of the EGR valve with hose detached. This area is probably better accessable with the wiper arms and cowling removed.

wiswind · #5 05-25-2005, 08:50 PM

I replaced my EGR valve...while trying to track down an intermittent problem. The EGR valve is not a high failure item. The DPFE (which senses the EGR flow through the pipe) is a much higher failure item. When I replaced my EGR valve.....I bought a can of "PB Blaster" and sprayed a SMALL amount on the threads of the EGR pipe....where it connects to the EGR valve. I did that a day before I changed the valve. Then I sprayed a small amount at the same location about an hour before I started the job.

JIMBOBX4 · #6 05-25-2005, 10:54 PM

Quote:

Originally Posted by 12Ounce

In the Haynes chapter 4 ..."Fuel and exhaust systems" ... does yours have photo 13.8? It shows the top of the EGR valve with hose detached. This area is probably better accessable with the wiper arms and cowling removed.

Yes, I have photo 13.8. Photo 13.12 is similar correct? I have concluded that my EGR valve location is similar to 13.12, but it is against the fire wall, and in the windstar impossible to reach. I can't even reach it sufficiently to verify the vacuum hose is connected. Is it reasonable to remove the intake plenum to work on this valve?
Thanks

JIMBOBX4 · #7 05-25-2005, 10:57 PM

Quote:

Originally Posted by wiswind

I replaced my EGR valve...while trying to track down an intermittent problem. The EGR valve is not a high failure item. The DPFE (which senses the EGR flow through the pipe) is a much higher failure item. When I replaced my EGR valve.....I bought a can of "PB Blaster" and sprayed a SMALL amount on the threads of the EGR pipe....where it connects to the EGR valve. I did that a day before I changed the valve.

Was your engine a 1999 3.0 liter? Was your EGR located toward the front of the compartment or back by the firewall?

12Ounce · #8 05-26-2005, 07:29 AM

"Is it reasonable to remove intake plenum......?" No.

What is reasonable .... is to remove the wiper arms ... and the two-piece cowling in front of the windschield. Once you do this the first time, it will not be so intimidating thereafter.

12Ounce · #9 05-26-2005, 07:44 AM

For "Cowl cover - removal and installation", see Haynes chapter 11, section 28.

5 steps.

wiswind · #10 05-26-2005, 07:19 PM

Mine is a '96 3.8L.
Pictures of locations of various things are posted at
http://community.webshots.com/album/201931518cScpNK

I removed the Throttle body to gain access to my EGR valve......removing the wiper cowling would not have helped in my case....as my EGR is not back that far.

JIMBOBX4 · #11 05-26-2005, 07:24 PM

Quote:

Originally Posted by 12Ounce

For "Cowl cover - removal and installation", see Haynes chapter 11, section 28.

5 steps.

Ok, I think I got it. I should be able to check this thing out.
Thanks for the advice. If I find anything, I will post back.

JIMBOBX4 · #12 06-02-2005, 05:24 PM

One more thing. Can I check for a potential disconnected EGR hose by connecting a vacuum gauge to an intake manifold hose? If so, what is the correct reading for normal operation at idle (14-inches hg)?
Thanks

12Ounce · #13 06-02-2005, 06:48 PM

I think the only way to know that value is to have taken and recorded it when there were no issues.

Boy, wouldn'd we all be so smart ... if, when the auto is still pretty new, we went around all over the engine box measuring (and recording) sensor voltages, pressures, vacuum levels, .... wouldn't that make a great maintenance reference notebook!

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