Need some help. PO401 code

[tsweers89]

I currently have a 98' explorer XLT v8. I have a MIL with a po401 EGR Flow Insufficient code. I'm assuming that the egr is bad. I cant pass emissions the way it is. You guys agree with me on a bad EGR. Also if i were to order one would it come with the gasket and stuff with it or would i have to order them seperatly?

Any info or comment would be appreciated.

Thanks

 

[Turdle]

I currently have a 98' explorer XLT v8. I have a MIL with a po401 EGR Flow Insufficient code. I'm assuming that the egr is bad. I cant pass emissions the way it is. You guys agree with me on a bad EGR. Also if i were to order one would it come with the gasket and stuff with it or would i have to order them seperatly?

Any info or comment would be appreciated.

Thanks

This could be very simple--
first-look to the rear left of the intake manifold for the egr selenoid, and DPFE sensor--
Now , looking at the passenger side intake manifold-look for a 5/8" metal tube going up to the egr valve. This is the EGR tube
Look for 2 smaller lines coming off the egr tube-going to the DPFE sensor. Remove the smaller rubber lines and look them over real good for holes-especially on the ends-
Look for a crack, in the egr tube -do you hear a slight exhaust leak?

Once you find the lines are all sealed up, and there is no exhaust leak-clean the egr valve-it might be sticking. Look at the vacuum solenoid line for leaks.

If the code still persists, then replace the DPFE sensor.

Welcome to the forum!!

 

[tsweers89]

Any way to get pics of this. The egr valve is the thing kinda behind the throttle body that looks like a fuel pressure regulator correct. HAs a small tube connected to the top of it. From there were do i go for these lines.

Thanks for the quick response though

 

[tsweers89]

Were is the DPFE sensor located in comparison to the actual EGR valve.

 

[Turdle]

Yes-that is the egr valve-
the tube you mentioned is the egr tube--follow down it until you find the 2 smaller lines running off it-
follow those smaller lines to the DPFE sensor. It is kind of hidden, but you can see the top of it-it's mounted on the same bracket as the egr vacuum solenoid-on the rear passenger side of the intake manifold-toward the firewall-

 

[tsweers89]

What is the other fuel pressure regulator looking thing that is kinda to the left of the EGR valve? It looks the same as the EGR valve but smaller. Also how do i go about cleaning the EGR valve?

 

[Turdle]

What is the other fuel pressure regulator looking thing that is kinda to the left of the EGR valve? It looks the same as the EGR valve but smaller. Also how do i go about cleaning the EGR valve?

If you are talking about a black plastic thingy with a vacuum line-it is the coolant bypass valve-cuts coolant flow to the heater core when using AC


To clean the egr valve-you must remove it, get some carb cleaner and go to town. Rinse it well --you can test the diaphragm by applying vacuum to it-

(I didn't tell you to suck it--lol)

make sure you get a good seal when re-installing it. You could use "mega copper" Perma-Tex for this. It will take the heat pretty well.

 

[tsweers89]

What does DPFE sensor stand for? And if the hoses and such are ok why do i need to replace this and not the EGR valve itself?

 

[Turdle]

Differential Pressure Feedback EGR

It monitors the pressure difference between the 2 lines, to insure the egr is indeed flowing--
Inside the egr tube is an orifice-right between the 2 smaller lines-this creates a pressure differential-

 

[manaen]

I agree with jsmith on that one, there is also a slim chance that the EGR tube is clogged, I have seen them completely get blocked by carbon. But I would check the DPFE first make sure non of the vacuum lines are leaking that go to it. This code is most often caused by the DPFE going bad.

 

[tsweers89]

So i prob wont need to change the EGR valve itself. Most likely the DPFE sensor correct

 

[manaen]

You got it

 

[tsweers89]

So i just took off the DPFE sensor and disconnected the two lines going to it. The lines are ok. No cracks or anything but one of the nipples that the lines went to one the sensor is all corroded and the other one you can see is somewhat corroded inside because it isnt a perfect circle. So should i replace it?

 

[Turdle]

Yeah--if all else looks good-replace the DPFE and clean the egr valve-
You might also clean out the egr tube while you are dirty-

 

[chaingang]

Any update on this thread. I too have this issue on my 98 V8, except mine is going to be a broken EGR tube most likely. Have a nasty exaust leak somewhere at the back of the motor and figure it is the tube. Does the upper intake need to come off to service the valve and tube? Would like to do the TM Headers also, should I wait to fix the EGR tube at the same time? Just found the site, lots of info here.
Thanks,

 

[Turdle]

Chaingang--
you are on the right track-
your intake can remain in place.

You'll need a new tube for the headers-so I'd get it with them. Ask Robert

 

[chaingang]

Man that was quick. That's what I call service. Thanks.
I see a lot of guys have these headers and have had them for sometime, any problems over the long term and have they been well worth the cost and effort to install.