Phoenix Reduces Their Models

quote author=Ron Dittmer


"On this past trip, our E350 chassis died while driving on Interstate 90 which required a tow. 

The mechanical failure turned out to be the E350 fuel pump control module, a $150 part with an electrical connector on it, mounted on the frame between the fuel tank and engine."

The Dreaded FORD Fuel Pump Failure

Reports of this problem occurring are abundant, widespread, and concerning  Contributors to the PC Forum and many other RV blogs report their being stranded with Fuel Pump failures.  Often, the failure is sudden and complete.  Some victims report the threat can be mitigated by driving only when the fuel tank level is above half-full. Other victims observe the combination of driving uphill with a partial tank will instigate fuel deprivation caused engine stoppage.

Many who have experienced the problem refer to a Fuel Pump Reset Switch.  Supposedly, located under the passenger side kick panel, it can be relied upon to regain normal operation.

I am wondering if the replacement Fuel Pump Control Module is considered an upgrade and has a higher degree of reliability than the original

I am wondering if the replacement Fuel Pump Control Module is considered an upgrade and has a higher degree of reliability than the original.

I wonder too.  I would hope that Ford has recognized a "premature failure" condition and made some changes to that module.

Do the articles say what the problem is that can be solved with a reset? I had a car MANY years ago that kept quitting in the same place on my commute. My mechanic figured out it was "vapor lock" of the fuel pump. Being poor I couldn't afford to fix it for a good long while so he taught me to whack the pump with a rock. It worked like burping a baby. That rock became part of my tool kit.

About our Fuel Pump Driver Module (FPDM) road-side failure.

We were cruising 65 mph on Interstate 90 when the engine suddenly died as if I had turned the ignition key to the "off" position.  I rolled the rig off to the shoulder to a dead stop.  After some thought, the first thing I checked was if the fuel pump was working.  I turned the ignition key to hear the fuel pump make that humming noise but I heard nothing.  It was terribly windy outside (the wind noise was very loud) so I crawled under the fuel tank and had Irene turn the key, but I still heard nothing.  The next thing I did was inspect fuel pump fuses.  Under the hood, I quickly found a blown yellow 20 amp fuse.  I replaced it and it blew again when trying to start the engine.  I replaced it again, this time also replacing the supporting relay with the one from the HVAC blower motor (they are the part number).  The engine started, so I thought all was well and so we continued on our journey.  That lasted about 5 miles and the exact same failure happened again.  Now we were 25 miles east of Buffalo WY (5 miles further away), and 45 miles from Gillette WY, further deeper into questionable cell phone coverage.  I decided to call it quits and call a tow truck.

If I had a bag full of spare relays and fuses, I would have been tempted to keep feeding them until we got to Gillette, a decent sized city for finding a repair center.

I did not tamper with the fuel pump centrifugal reset switch located in the passenger foot well, though I should have to rule it out.

I did not open and close the fuel filler cap to release fuel tank pressure, though doing so would have been a good idea.

I did not know a FPDM existed on our E350 chassis until after the repair.

I initially considered, but quickly ruled out hitting the bottom of the fuel tank to jolt the fuel pump awake because the fuel pump was already running and suddenly stopped working.  The "fuel pump jolt" is always a remedy when trying to start a vehicle, not for a vehicle running that suddenly shut down.

I was reading on another RV forum, a poster asking where his E450 fuel filter is located.  That got me thinking about our fuel filter.  Dummy me, I never changed it.  Our E350 has 42,000 miles today.  I have the big service manual for our 2007 and just now read that I should have replaced the fuel filter at 30,000 miles, so it is OVER-DUE by 12,000 miles.  That is not horrible, but it is over-due none-the-less.  Maybe a restriction in the flow of fuel was influential in the system failure.  I think flow-resistance is unlikely the cause for the FPDM but you never know.  I will be replacing the fuel filter before going anywhere in our PC again.

footnote: Earlier I was calling the Fuel Pump Driver Module (FPDM) a fuel pump control module.  Ford calls it a "FPDM".

That looks like a big power transistor or DC  voltage regulator or converter. Perhaps it was an  added safety measure that was part of the change to a drive by wire throttle body, or just a change to a different  fuel pump assembly. It’s unfortunate that these types of electronic failures don’t throw a DTC.  I have the old cable type throttle body and it took me a long time to  chase down a bad TPS that was still causing intermittent upshifting problems, after the corrupt local Ford dealership charged me a $125 diagnostic fee for doing nothing and tried to sell me a remanufactured transmission. 

You were indeed very fortunate to be towed to an honest and competent Ford dealer service department. If my E350 had a FPDM I would definitely be ordering a spare to keep in the emergency tool kit (RockAuto shows multiple sources), along with the spare self-resetting breaker for the house battery charging circuit 

The part name says it all. It drives the fuel pump.

Ford has the bulk of the cutaway market and I wanted to know of any quirks others would share.  I learned this controller is a fairly common and well known problem by reading the various RV Forums.     

Among those rigs accumulating mileage, it seems the fuel pump driver module issue is the most often mentioned.  Corrosion is the culprit.  The module is made of a die cast type material and plastic.  And, like dissimilar materials, the die cast corrodes badly when mounted on the steel cross member  If this part corrodes enough, it just stops working.  Pictures accompanying the reports of failure showed severe corrosion perforating the outer shell and causing case separation  Loss of the circuit board's isolation and exposure to debris is the culprit.

Considering the replacement part includes standoff mounting washers to isolate the controller, I think that feature alone is enough to prompt me to do the installation.  I will consider the takeoff as a spare, if it isn't already demonstrating severe corrosion.  The other item for next spring before making the first trip is to locate the elusive Fuel Pump Reset switch that other claim is behind the kick panel on the passenger side floor.

My investigation found that often times the engine stoppage is wrongly diagnosed as a bad fuel pump which can be costly to replace when its not the actual issue.

Taildragger,

In my case with my 2007-V10 fuel pump driver module, there was no corrosion involved.  I even opened up the unit to see if water got inside.  It was well sealed and perfectly clean inside and all solder joints looked good too.

I removed the circuit board to recycle it properly.  Here are the electronics of the FPDM.




I designed hard circuit boards, flex circuits, and thick film circuits for Motorola all my adult life, 12 years in Motorola's Automotive Division 1977-1989.  Ford was our biggest customer back then so "This Is My Thing".

Something that stood out to me as a potential problem with the design are the two power components positioned between the two screw holes in the first picture.  They sit on the thick fiberglass FR4 circuit board with thermal grease behind them on the back side.  They are not heat sunk properly.  They should have hung off (or holes through) the circuit board and screwed or clamped directly on the alloy casting.  If they are not a ground contact, then use very thin insulator pads.  The heat is not able to efficiently pass from the components through the circuit board, to the alloy casting.  Therefore I suspect one of those two power devises overheated and failed.  They need not appear "fried" to fail internally.

I feel the design is potentially flawed, an effort to save a little money.  I frequently seen such poor design practice with Motorola's competition.  The units pass the customer robust operational specifications, but when conditions are just right, a failure still occurs.

Ron, you never fail to amaze me...

To simplify, the FPDM regulates the fuel pump supply voltage as a way to regulate the system pressure to achieve best mileage and emissions.   If the pump gets full voltage 100% of the time, it can affect mileage and emissions. Wont hurt the pump, however. 

This was a necessary item to have once they eliminated the fuel return line to the tank to decrease emissions, as the older style pressure regulators could not be used anymore. 

The FPDM can be bypassed to 'get you home'.

This is for educational purposes only.     ................found a good pic of the jumper configuration needed for Ron's (and my) style FPDM. This is NOT how it should look before you get back underway. This picture just shows a setup to test and verify the FPDM is the cause. If you need to have it work for emergency travel purposes, fasten and insulate things so road travel will not dislodge the jumpers or short them out!!



On the source thread, you can see what a heavily corroded FPDM looks like. 

Source - https://www.ford-trucks.com/forums/1645900-quick-diagnosis-for-fuel-pump-driver-module.html


 Despite corrosion seeming to be the cause most of the time, Ron D seems to be on a good diagnostic track with his dissection and analysis of his non corroded unit. I would agree that the power handling devices he mentioned are shorted/shorting to ground, blowing fuses.


But hey, for my 2006 (says it fits ""2004-2008 Fo-rd (sic) E150 E250 E350 F150 Super Duty 6.8L V10 & 5.4L V8"") and for $30, might be a good spare to have with..

https://www.amazon.com/4C2Z9D372BA-6L1Z9D372AD-Freestar-Explorer-Mercury/dp/B084ZBPZHK


or the Dorman number (590-001) comes up as 'in stock' and ~$110 at the auto Zone, also at O'Reilleys, also Discount Auto, but only $95 and in stock at NAPA. 

So not a hard item to source, but I bet they are scarce when you are broken down on the road. 


Topic drift.... where the best solutions hide.     

..........Ron D seems to be on a good diagnostic track with his dissection and analysis of his non corroded unit. I would agree that the power handling devices he mentioned are shorted/shorting to ground, blowing fuses..........

Hi Volkemon,

About your comment, you misunderstood me.  To clarify.....

"IF" the two power device internal heat sinks could be grounded, they should have been attached directly to the alloy casting, not to the circuit board because that green board is a good insulator, hence those two parts operate at a much hotter temperature which a bad thing.

"IF" the two device tabs are not permitted to be grounded (a uncommon case) then they should have a micro-thin insulator to the alloy casting to minimize their thermal isolation.

When engineering refuses to spend the money on proper heat sinking like in the FPDM example, the circuit board designer should have maximized the copper on the circuit board around those component bases to absorb the heat to act like cooling fins.  It is simply good PCB design practice that comes at no cost.  I wonder if my FPDM would have lived had there been more PCB copper retained around those two parts.

Gold instead of copper would have been even better, but obviously more costly.

The design of anything is always a compromise.  Last I heard, nothing is perfect, everything has some form of flaw.

So the fuel pump uses pulse width modulation to vary the duty cycle. All that to eliminate the fuel pump return line as a source of vapors. Gotta love Cal EPA.

D1 and D2 are diodes. Simple  enough to measure  if they are shorted across the anode and cathode.  They really should have been located on the back side of the pcb, with heat sink compound between the tops of the cases and the housing. But that would have added another layer to the pcb and increased the cost by a few dimes  . And they could have prevented  any potential corrosion issues just by potting it.

All the more reason not to pay premium prices for Motorcraft brand electrical parts, when the stuff from Oreilly or Autozone is cheaper and has a lifetime warranty instead of 12 months.

At least you didn’t have to get towed to the nearest  MB or VW dealership, and rest easy knowing that even in the middle of nowhersville USA those common good ol Ford truck parts are always available , unlike many single source oem Bosch parts that likely would have been obsoleted and discontinued by now. Been there done that. Hope you had Coachnet or equivalent with towing included . Keep calm and carry on 

Like mentioned on this thread, it would be smart to carry a spare module.  It is easy enough to replace on the side of a road.  Just remember to include a spare supporting relay and fuse.  When my module failed, it took out both of them.

Ron, the question becomes what spares are needed. On a trip I had a shock break, should I carry a spare? My gen starter failed should I carry one of those too? How about a engine starter or a coil pac, an egr valve and so on. Some will cause you to be dead in the water others a inconvenience etc. There’s so many things that could possibly go wrong or none at all. It takes forever right now to get parts as well. It’s all basic risk management. A person could spend a couple grand on just in case parts and still not have what’s needed when it hits the fan… Murphy’s law. 

Joseph, you make a good point.  Where does one begin, and then how far does one take it?  It comes down to "peace of mind".  Some people carry a spare tire and have never used it.  Others don't carry a spare tire for that same reason....they never needed one, so why carry one?