96 5.0L P0402 but no DPFE Sensor?

[cbr rob]

96 5.0L P0402 but no DPFE Sensor? **UPDATE - FIXED!**

Hi guys and gals.... Love the board. Lot's of great info here... I've been searching the board here for the answer but have not found it. Please forgive me if this has already been asked...

I have a 1996 XLT Explorer with the 5.0L. I am receiving the p0402 EGR Flow Excessive code. I understand this is usually related to the DPFE sensor, but for the life of me I can not find it. I do not have the riser coming off of the Passenger side exhaust manifold, so I can't follow the lines from that to the sensor. I have followed the lines from the EGR valve itself to a sensor, but that one does not look anything like the pictures I have seen of the DPFE.

So my question is, does this model year even have a DPFE? If it does, where the heck is it? If it doesn't, what are my options on how to clear the p0402 code? Thanks in advance!!

***UPDATE - FIXED!!!***

So after two months and several weekends of troubleshooting, I was able to clear the codes and not have them return. Turns out that the EGR valve was working, but it was not closing all the way. It was a a little coked up at the plunger end (135K on the odometer) which did not allow it to close completely. This in turn did not allow the position switch to fully extended, telling the computer that the valve was still open, throwing the "EGR Excessive Flow" code.

So, long story short... I changed the stupid EGR valve ($130, which is why I wanted to check all other options first) and all is well. It's not too bad of a job, but you have to remove the Throttle body elbow (Ford calls it a Throttle Body Adapter). Make sure you pick up the gasket from Ford for this adapter because coolant runs through the elbow, and you will need to replace it.

 

[410Fortune]

This is a pic of the 96 5.0L PCV valve location, but you can also see the EGR setup on the right.

Your code is excessive flow, but doesnt necessarily refer to the DPFE

You dont have an EGR tube because your EGR connection is made inside the intake manifolds and the intake elbow. This is why your EGR valve is mounted on the back of the elbow

You do not have a DPFE on your model
but you do have excessive flow, so check your vacuum lines then the valve itself.
I have had two 5.0"s where the orange diaphram itself inside the valve has a tear in it, and gave me the same code, on both different EGR 5.0L setups (with tube and without)
I have my $$$ on that sucker


http://fordfuelinjection.com/index.php?p=35

http://fordfuelinjection.com/index.php?p=43


Hope that helps!

 

[cbr rob]

Thanks for the reply!! Just to get my head around this.... If the EGR valve had a tear (assuming) that would mean the valve does not open, and this would cause a EGR Excessive Flow? Correct?

Is it possible that the EVP sensor is bad? How 'bout the EVR? That EGR valve looks like a huge pain to replace. Interesting that your picture shows the EVR right next to the EGR valve. My EVR is up next to the IAC Valve.

Thanks again for the info. I'm just trying to pin down the right part without buying up everything in the parts store and replacing items one by one.

 

[410Fortune]

climb up on the engine and get back there and look.
Check vacuum lines first

Then plan on removing the intake elbow, this is the fastest way to get the EBR valve on and off, for inspection or replacement.
When I bought a replacement for my 98 model 5.0L (with p heads, not 96-97.5) I had a hard time locating the correct part at the parts stores, their books kept trying to sell me the 96 model. So its a good idea to get the part number off anyways and removing it is the best way to inspect the vacuum lines, wiring, gasket, and valve itself. ON my 96 with a 3" body lift I can remove the valve without taking the elbow off but its a real PITA, and I find the intake tube, throttle linkage and 4 bolts for the elbow are much faster (10 min job)

You can use an OHM meter to check both the flow regulator and the pintle sensor as discussed on those sites, but those sensors RARELY go bad, if ever.

 

[cbr rob]

Thanks for the info 410Fortune. I went home and checked the EGR valve for operation. It pulls down smoothly and holds a vacuum with about 5-6 inches applied to it. So I figured the culprit would have to be one of the two sensors. Picked up the Position Sensor and the Regulator. You guessed it.... no luck. Still pulling the P0402.

Autozone wants $129.99 for the EGR valve itself. All lines and wires look good, and as I mentioned earlier, it pulls and holds a vacuum. Do I need to replace the EGR? Is there anything else I need to look at?? Thanks again for all the help....

 

[410Fortune]

have you tried clearing the code???? comes right back?

 

[cbr rob]

Yes. The pending code comes back within a few miles.

 

[410Fortune]

http://www.obd-codes.com/trouble_co...recirculation-flow-egr-excessive-detected.php

hmmmm

did you inspect the vacuum line 100%?
You can either buy the new valve and replace it and risk having the code come back
OR
you can remove the elbow, then possibly the intake to look for blockage/bad gasket, etc
and then possibly still have to buy a new valve.

How many miles?

If it helps there was not alot of carbon build up when I had the intakes off either of my 96 5.0L engines, one had 154K miles, one had 83K miles and they both looked similar internally.
I did replace all the geskets, I cut them myself from sheets of gasket material though so its cheap...

I did not test my valve by applying vacuum to it, I cleaned it up a little bit and then saw the tear, bought a replacement, bolted it on, and the excessive flow code went away.

I am thinking the orange bladder is what gets pulled up by the vacuum and opens the EGR flow, right? So it may open and close, even with a tear in the side of it (meaning the vacuum line only pulls on the middle of it, not the entire diaphram because its in a metal cage with holes on the back side. So even though it is holding vacuum its possible its opening and closing, but the EGR flow is still not being controlled....
I dunno, not sure without a DPFE how the computer would know?
is the check engine light on? does the truck surge at all? engine run okay?

 

[Turdle]

I don't understand the egr system on pre external models all that well, but my thinking is that the valve is sticking open-not closing completely.
I would clean the egr valve real good.

 

[410Fortune]

JT smith, well they are basically identical to your setup, except the EGR feed is through the head/intakes

there is no DPFE because there is no easy to get at tube to hook it up to so it can monitor the flow.

 

[Turdle]

JT smith, well they are basically identical to your setup, except the EGR feed is through the head/intakes

there is no DPFE because there is no easy to get at tube to hook it up to so it can monitor the flow.

So
Does it monitor the flow by actually monitoring position?

If so, stuck open would be high flow?

 

[cbr rob]

Well, I did confirm the line from the Regulator to the EGR valve was 100%. I attached a vacuum line and fitting to it and pulled a vacuum. I watched the EGR valve pull down and hold no problems. The other side of the regulator is the vacuum source so that is always pulling down.

One question....when vacuum is applied to the EGR, is that open (excessive flow) and when vacuum is release, is that closed (insufficient flow)? Or do I have it backwards? I'm wondering if TOO much vacuum is being applied to the valve.

As far as I can tell there are only three parts to this system. The EVP, EVR and the EGR valve itself. The only thing that I believe reports to the ECU is the EVP. There appear to be no sensors that actually measure the amount of exhaust gas flow (like the DPFE does).

Thanks for the ideas

 

[410Fortune]

I want to say yes, but would have to compare my BII to my 96, i get the differences all mixed up

 

[410Fortune]

the external setup does not have the position pintle sensor does it?
if so then thats the difference and how it measures flow

 

[Turdle]

OK
in 410's pic above, there is a black thing with a red and brown wire--see it? very far right.
EGR solenoid

Disconnect that plug and see if the valve closes.
That solenoid is sticking huh?

or
is there a chance the two vacuum lines going to it are crossed?

 

[410Fortune]

he replaced it, thats the vacuum regulator, all it does is turn the vacuum supply to the valve on and off, they RARELY go bad

 

[Turdle]

The egr valve shouldn't be open at idle, should it?

 

[cbr rob]

The EGR valve is the same as the one in the picture. It does have the Position Sensor on it, and it was replaced today as well. Just for gits and shiggles I went out and measured the vacuum source. I'm pulling just over 20 inches. All lines looks good.

This is driving me nuts.

 

[cbr rob]

Just for clarification... what is open? Vacuum applied to EGR, or NO vacuum?

 

[410Fortune]

I assume vacuum opens the diaphram and increases flow

however if the diaphram is leaking/ripped then it wont do a damn thing to flow and it will likely always be excessive

Bottom line is you have replaced 2 out of 3 of the EGR components.
I seriously doubt it is carbon blockage internally
You checked the vacuum lines and wiring

so..............

also if the sensor was faulty (pos sensor) you would not get an excessive flow code, but a no switching code, so the sensor is doing its job, well at least we know that now since you replaced it, i guess if it was stuck it could cause all sorts of codes