Hi, I seriously need some help here. I am pulling my hair out.

I have a 2006 expedition. Has run great for ever. Then this Tuesday if just quit. Had the check engine light come on.

It would re-start, but would quickly die seconds later.

It was a bit low on oil, as well as coolant. Topped all that up.

I figured it was fuel related. Turned over nice and everything else seems to be OK.

I checked all the fuses for the FPDM and the Fuel Pump Relays. Checked anything that looked fuel related. No blown fuses.

Even swapped out the R203 Fuel Pump relay. Nothing. No difference.

Ear to the tank could not hear the fuel pump running or anything on the key cycle. Banged the tank a few times still nothing.

So pulled the fuel line off of the fuel rail and cycled the key. No fuel pressure. Nothing.

Checked power at the Inertia Fuel Shut off. I have power to the Inertia Fuel Shut OFF (on the dark green wire) and leaving the Fuel Inertia Shut Off (on the solid white wire). So, I know I have power coming through the Fuse Panel through the Fuel Pump Relay to the Inertia Fuel Shut Off. I know I have power leaving the Inertia Fuel Shut Off. All shows 12v.

I have 12v power to the FPDM (on the solid white wire) from the Inertia Fuel Shut Off.

Oh, pulled the FPDM out and it was corroded all to heck. Looked just like everyone else's photos of failed FPDMs. Not pretty. I replaced that for $149 plus tax (+/- $200 at Ford). Still nothing.

Fuel gauge in the car works just fine. Showed 3/4" of a tank which is correct.

I have no error codes.

With every thing looking good, I figured the Fuel Pump must have gone when the FPDM rotted out. I was told they sometimes both go at the same time by a parts guys at the Ford dealership. Fuel Pump from Ford was quoted at $630. From local parts store $480

So, I figured the next thing to do was to pull the tank. Fun times with 3/4s of a tank of fuel, but got it all out in to multiple gas cans.

Pulled the tank and bench tested the fuel pump. The fuel pump works.
I put the pump back into the tank and testing it again. Now pumping out all over the floor, OOPS! yes the fuel pump still works.

Where I sit now is with the tank still out of the Expedition and testing the power to the 4 wire Fuel Pump power connector. Still no power to the Fuel Pump plug on the key cycle.

Going back out to the garage to check the continuity of the power lines from the FPDM to the Fuel Pump. Maybe a broken wire. Although I am doubting that. The wire casings are all in pretty good condition.

I am not sure where to go from here. If the wiring checks out between the Fuel Pump Plug and the FPDM, then the entire fuel wiring side checks out to be good.

I think that only leaves me replacing the PCM for some $300-$400 + at FORD. But I don't just want to throw parts at it.

Someone please tell me there is a magic button that I forgot to push to make this all go away !!!

Please help... I am lost at this point.

I have read about the infamous non-serviceable R303 Fuel relay module. I cannot find it. I read it is on the back side of the Fuse Panel. But took off the bolt to swing the Fuse Panel and look behind for something melted, but it all just looks like solid plastic. I do not see any relays back there or anything that even looks like a relay casing. Maybe need to look harder.

Do I replace the Fuse Panel to replace the R303 ? Question, doesn't the fact that I have power to the Inertia Fuel Shut OFF switch mean that the R303 relay is working ?

Or am I looking at the PCM ?

My head hurts !!!!! Please help.

I am going to sit down and have a beer and scratchy head some more.


Thanks in advance.


Kevin

 

Wire colours are a bit different. But the concept should be the same.

Kev

 

PAT security. I do not believe it is the PAT security disabling the engine. because when the vehicle first quite, it would restart and run for a bit then quit. A different interval every time. If the PAT disabled the vehicle it would not start up at all. Eventually, after many starts and quits the vehicle will no longer start. It does turn over, seems like it is trying to fire on fumes.

I found a neat way to check the Inertia Fuel Shut Off power. I removed the drivers rear tail light and then the wiring plug through the body. From there I could pull the smaller wrapped wires and cut back the casing. Found the Dark Green / Yellow wire from the Fuel Pump Relay and the white wire going down to the FPDM. Later cut back some plastic to view into the Inertia Fuel Shut Off and confirm they were the correct wires.

Took two small pins and poked them into the two wires. Was able to test voltage on both. Pushed RESET button on top of Inertia Fuel Shut Off multiple times. No difference.

Now I keep reading that the power to the Fuel Pump will only be on when initially cycling the key. I am not sure this is correct. I have power there all the time.

It is my feeling that when the key is cycled the fuel pump kicks in and builds pressure in the fuel system to a specific PSI then it shuts off. So in a working correctly system, pressure builds quickly and the pump shuts off.

However, in my scenario, there is no PSI build up so the system keeps sending power to the Fuel Pump waiting for the PSI to reach its spec, and then shuts off. As mine never builds PSI, power stays turned on to the pump.
Does that make sense ?


I keep thinking that because the power is getting to the FPDM, I am thinking that something from the PCM must be not allowing the FPDM to send power to the Fuel Pump.


I'm I insane, or am onto something here.


I keep reading through all the other posts here where guys did not have power to the Inertia Fuel Shut Off and found a melted R303 or failed relays. As I have power, all those relays must be functioning correctly ? Yes ?


I am leaning towards PCM replacement !

Thoughts ?


Kev

 

Sorry everyone, lots of posts, but lots of question and thoughts.



What about something weird going on back at the Evaporative Emissions Canister Vent Solenoid ?

Could the Fuel Tank Pressure Sensor cause this ? I have not put the tank back in yet. Think I will replace that in good faith, just cause the tank is out. Cannot be that expensive.

 

If you're getting power into the FP module, but not out to the pump, it would seem to me the problem is right there. Have you tested for power directly at pins 2 & 4 of the FP module when turning the key on?

 

No DTCs? No pendings?

So you have power to pin #5 of the FPDM connector. That's good.
Now do you have a ground on pin #3 of the FPDM connector?
(The FPDM needs power AND ground to do its thing. Additionally pin #3 provides the ground for the fuel pump.)

 

Going to add some photos for some extra splash, haha.

Question:
I am adding photos from my public DropBox, so once I delete them out of DROP BOX they will be deleted here (I think, as the link will be lost). Is there any way to permanently attached photos to these posts (sorry a bit off topic).

Here is a pic of my old FPDM



In order to prove continuity, I jumperred everything. The FPDM and the Inertia Fuel Shut Off (IFSO).





Now I have power to the IFSO plug, jumped down to the EPDM, jumped to the Fuel Pump.

Using the electrical tester, I pushed tested ends into the Pink/Blk (power) and Brn/Org (ground) at the Fuel Pump Plug and I now have power to the Fuel Pump Plug with the key ON. Power is there ALL THE TIME as long as the key is ON. No cycling and shutting off, which makes sense to me as the fuel pressure did not build to 35-70 PSI and shut off. This tells me all the wiring is working with full continuity.

With full power right out to the Fuel Pump now, I am ruling out Fuel Pump Relays R203 and R303. I think that is a safe assumption.


Working backwards. I unplug the jumpers at the FPDM and plug in the FPDM and loose power to the Fuel Pump with the key ON.


So the million dollar questions is,
- is it a faulty FPDM or
- is there something from the PCM telling the FPDM to not allow the power trough to the Fuel Pump
- or is it the plug harness itself not contacting the connectors on the FPDM

Need to do some more testing on the FPDM and the plug I guess.



Thanks for your posts guys. Greatly appreciated.

Alloro, thanks
I was thinking the same thing after a beer last night, so back out this morning and all above is what I found.

pdqFord, thanks
I only have a simple code reader. I show no codes. I pulled a bone head move though. When the truck was first starting and failing I wanted clean codes. So disconnected the battery to wipe codes, but did not read them before i did that. Thought the vehicle would start right back up for a bit and spill codes, but never got it started again. No new codes. Don't really know what I as thinking...dumb move. Anyways.. I have to live with that now.

There are 6 wires on the FPDM plug (either 1 or 6 is white where I have power down from the IFSO). Wires are as follows in this order across the plug.

white (power from IFSO) - Power is Good with key on.
pink/blk (Power to fuel pump) - Power is Good when jumperred out to the Fuel Pump
bl/org (something from the PCM) - not sure what it does ?
bl/red (something from the PCM) - not sure what it does ?
One of the bl wires has power the other does not. Cannot remember which one.
black (ground) - Ground is Good to frame
black/org (ground from Fuel Pump) - Ground is Good when jumperred out to Fuel Pump.

So the fact that I now have power (in a jumped state) right out to the Fuel Pump, tells me my wiring is all Good.

Is the FPDM faulty ?

Is the PCM sending some signal through one of those two bl/org or bl/red wires that is telling the FPDM to not allow the power out to the Fuel Pump ? Is that even possible ?

From my wiring diagram above, posted earlier, the PCM reads the Fuel Tank Pressure Transducer Sensor. If this sensor failed in the 'full pressure reached' scenario, could it be telling the PCM that the tank is at a pressure that would cause the PCM to deny the FPDM to send power to the Fuel Pump ? Seems unlikely. My impression is that the sensor is there more for the emissions side and would not effect Fuel Pump operation ? Thoughts ?

Thanks for your help guys. I think I am getting close.

I am leaning towards inadequate contact in the FPDM plug itself,

or a faulty FPDM.


Any other thoughts ? Think I am on the right track ?

Or, is my PCM acting up ?


Kev

 

Apparently, the inactive/dormant state of the FPDM is to jumper both the power and the ground out to the Fuel Pump. Therefore with no signal sent to the FPDM the power will simply be passed through the FPDM out to the Fuel Pump.

So that answers my question if the FPDM is faulty or not. It is not faulty.

What appears to happen is that when a signal is sent to the FPDM, the FPDM is activated and breaks the power circuit of power to the Fuel Pump.

I have power coming to my FPDM that is activating the FPDM relay and cutting power to the Fuel Pump. I am temped to cut the power wire to confirm my believe, but then I would have to patch that wire up and make is waterproof again. I am pretty confident this is what is going on.

I know that when I bench tested the FPDM in the dormant state both circuits in the FPDM are in the pass through mode. This pass through would function exactly as I set the jumpers in the plug on the vehicle. Also shown in the previous posted photo.

So the question is

Why is the PCM sending a kill signal to the FPDM ?

Is the PCM failing ?

Or is the PCM receiving a signal from another sensor somewhere that is telling the PCM to cut the power to the Fuel Pump and kill the motor ?

What sensors would do that ?

I don't think the MAP would do that ? Truck has been running good. MAP seems to have more to do with running conditions, poor idle , lack or power, etc.

Low oil on my generator will kill the motor. Does that same condition exist on the vehicle ?

Would the Fuel Tank Pressure Transducer Sensor kill the motor ? Under what condition ?

I am not sure what else would cause this issue ?

I though I was getting close narrowing down items. However, it looks like I have just expanded my search throughout the rest of the vehicle.

Any thoughts?

Going to put it all back together, put the tank in, etc and jumper the FPDM and see if I get Fuel Pressure and a running vehicle. Maybe I can get it running long enough to spit some codes.



Kev

 

Ok, i put it all back together. With the exception of the FPDM
Left that plug with the jumpers bypassing the FPDM.

Truck started right up and rubs good. Put in the FPDM and it quits.

Something in the PCM is shutting down the FPDM

I can now read codes. Truck is reporting Pending code
P0191 Fuel Rail Sensor Circuit Range/Performance.

Generally a warning that fuel pressure is either too high , above 70 PSI, or to low, below 25 PSI

I am assuming that the fuel pressure is too high right now as the fuel pump is running continuously as the FPDM is not hooked up to control it.

I am trying to figure out how to get the fuel pressure. Guess i need to buy a gauge with a 'T' connector so i can check while running. My scanner device will not read it.


I guess that is the next step.

But don't know what that will tell me. I assume with the jumpers in at the FPDM it will ready too high. If I install the FPDM the vehicle will not run as the Fuel Pump has no power. No fuel pressure.

Getting that head ache again....

Any thoughts....

Will do more reading...and youtube...

Kev

 

There should be a Schrader valve on the fuel rail to be able to connect a fuel pressure gauge to.

 

No Schrader valve on the fuel rail in an 06. They did away with that.

Even checking fuel pressure is an issue.

If i install the FPDM the pump does not come on in order to test fuel pressure.

If I jumped past the FPDM the fuel pump is on all the time and will produce abnormal pressure readings.


I have now installed and removed the FPDM so many time that I broke the clip last time taking it off. Off to the auto wrecker tomorrow for a new plug and will see if I can pick up a FRS for a test. $174 at the local parts store, would be more at Ford. Big gamble to buy a new one just to test it.

My vacuum is running about 17.5 inches and steady. That should be good enough to not be concerned about vacuum leaks I think.



I am running out of things to check.


I simply cannot get the new FPDM to work when plugged in. I benched tested both the new and old FPDM. In their unplugged state, they let both power and ground through on the terminals. Just as I have jumped them with the wires.

However, once I plug the FPDM in the pump no lounger works. Very strange.

Does the FPDM reduce the voltage to the Fuel Pump, or does the Fuel Pump need 12v and does not run in a variable speed.

Seems I read somewhere that the pumps in the 2006 Expeditions, etc are a two speed pump.

still stumped...

Kev

 

Still searching...

going to start posting stuff here that seem relevant

Found this on another site...

_______________________________________

If the PCM is bad that one output could be shorted and the reset of the PCM works fine.

You need to check the fuel rail pressure sensor, if it reading bad, the pump may think the rail is charged.

the FRPS has three wires, BVREF, Signal and Ground.

They have some complicated Duty Cycle for the FPDM
if the Duty cycle command is 0-5% the pcm will not output, Invalid FP duty cycle, the FPDM sneds 25% signal to FPM circuit, The FP is off
if the Duty cycle command is 5-51% normal cycle, FPDM operates the fuel pump speed as requested.
if the Duty cycle command is 51-69 the pcm will not output; Invalid FP duty cycle, the FPDM sneds 25% signal to FPM circuit, The FP is off
if the Duty cycle command is 70-81% the pcm, is a valid command to request a fuel pump off the PCM will output a 75% duty cycle
if the Duty cycle command is 82-100, the pcm will not output; Invalid FP duty cycle, the FPDM sneds 25% signal to FPM circuit, The FP is off

When ever I have issues like this, I pull the battery for 15 minutes and try again, it supprizing how many computer output lock up or go into safe mode.
_________________


Going to see if this makes any sense at the FPDM

kev

 

I'm having a little trouble following your wire colors with the wiring diagram you previously posted. And I'm not sure just which pins you jumpered on the FPDM's connector.

Different years seem to have used different wire colors but I will describe how the returnless fuel system works using the FPDM's pin #s. Maybe it will help in your diagnosis.

The FPDM recieves battery power from the IFSO on pin #5 any time the key is in the on or start position.

The PCM, looking at the Fuel Pressure Transponder Sensor, the engine rpm, load, TPS, etc, etc, sends the FPDM commands on pin #6. The commands are Pulse Width Modulated signals of ~150 Hz. Normal commands are in the 5-50$ duty cycle range and 68-83% range are commands to shut the fuel pump down. (That's how the PCM runs the pump for a second or two at key on.)

The FPDM, which is a smal computer, does some calculations to determine the duty cycle of the power to send to the fuel pump on pin #4 with the fuel pump return path on pin #2. The actual fuel pump ground is supplied on pin #3. (You want to be sure pin #3 provides a ground back to the battery negative of less than an ohm or two.)

The FPDM sends a diagnostic signal back to the PCM on pin #1. This is a much slower signal (1 Hz) and has a 50% duty cycle if everything is running okay, a 25% duty cycle if an invalid or no command was recieved by the FPDM, and a 75% duty cycle if the FPDM detected a fault in the fuel pump circuit. If the diagnostic duty cycle received by the PCM is not 50% the PCM will set a trouble code. (Best way to look at the FPDM commands, diagnostics or fuel pump power is with a graphing multimeter or a lab scope.)

As you can see, just checking for power with a test light isn't going to get it. You really need to look at the duty cycles. Hpefully this overview will hep you with your dignostics.

 

Thanks for the post. I am going to look at that in the morning.

With respect to wiring, my wiring appears to be different. Looking at the plug, into the connectors, from left to right this is the order of the wires on the back side.

white (power from IFSO) confirmed
pink/blk (Power to fuel pump) confirmed

Then in the middle of the plug there are two wire stacked overt top of each other. These are
bl/org (something from the PCM)
bl/red (something from the PCM)

Then on the other side we have
black (ground to the frame ) confirmed
Dark brown/org (ground from Fuel Pump out to Fuel Pump) confirmed


I placed a jumper wire from the white to the pink/blk, that provides the power out to the fuel Pump

Then placed a jumper between the black and dark brown/orange wire which provides the return grounding circuit from the pump.

This allows the pump to run upon ignition. The wiring definitely sounds different than you explained.

The two blue wires in the middle, must be the power and negative wire for running the different signals with different voltages from the PCM. The blue wires are a lighter gauge than the other 4wires i put the jumpers on.

I broke the clip on the FPDM plug so off to the autowrecker in the morning, plus I am going to pick up a FRS and swap that out for kicks to see if there is any difference.

My feeling is that if it is not the FRS (once i re-wire the plug for the FPDM) that it is looking like the PCM. I am running out of other things to check.


Will post what i find out.

 

Well that's just dumb.