rjg426

Hi All,


I know there is a lot of information about these but I wanted to add a little more about my experience with this failure that might help someone else, because it is due to this forum, and others like it, that I was not left stranded 300 miles from home last weekend. Turns out I had a bad Fuel Pump Driver Module. It didn't fit the majority of symptoms which seem to be no-start problems. Here's the story.


My truck's a 2008, 4.6L, with 117,000 miles that I bought used 2 years ago. The truck always ran fine with no symptoms until we were a few miles from our destination for the weekend, 300 miles from home.


It suddenly started bucking, mildly at first but quickly developed into a severe, I'll call it rhythmic, bucking. Any attempt to accelerate at all caused bucking in a rhythmic sort of cyclic pattern of power then dead then power then dead, etc.


We were able to drive slowly for short distances this way but it was seriously not right. I thought it might be a coil/plug problem but it seemed too severe for a single cylinder missing.


There was no Check Engine light on (the light is functioning) and I had my scanner with me and there were no faults detected.


The truck ran fine the next morning at a cold start after sitting overnight. After it reached close to normal operating temp the problem began again and continued.


Then while parked and idling, I faintly heard the fuel pump cycling on and off. I hooked up the scanner to view live data, and found that the Relative Fuel Rail Pressure was fluctuating. That's when I started searching for fuel pump problems and realized it could be the FPDM. I would have normally brought it somewhere to have the fuel pump replaced and would have had to most likely leave it and rent a car to get home, then drive back to pick it up, since we had to leave for home that day.


There was only a local NAPA store in the area, and they had the FPDM in stock. I paid $35 more ($98.49 plus tax) than Amazon Prime, but that was fine with me since I had my hands on one immediately.


Needless to say, it solved the problem. The old one was corroded but not split or broken like I've seen pictures of. I didn't open it yet to see what was going on inside, but obviously there was a malfunction in the circuitry somewhere. The connector and wiring looked good. The truck was back to normal with the new module, and ran fine for the trip back home, and to date with a few hundred more miles on it since.


BTW, the NAPA part (600-5477) is actually Dorman (has the Dorman sticker and part number on back). It also comes with the standoffs.

techrep

iTrader: (1)

Nice...

gmctech

I have my first Ford truck that i've ever owned and got the dreaded P0191 code. took the module off and it was super corroded and took the module off and it rattles when shaked. It only happened once but all the great info on this forum helped me to go right to the issue right away. I had surging at highway speeds that lasted a few minutes then went away. ordered a new module and know that it will solve my problem. My truck is a 2004 new style with a 5.4 and its in great shape but this darned module could have left me stranded. I opened it up and the corrosion is everywhere inside so i used electronics cleaner and filled it with dielectric grease and resealed it to get me by till my new module comes in.

techrep

iTrader: (1)

I wonder what non conductive dielectric grease in there would do ?

gmctech

It's working like a champ with a whole tube of dielectric in there. Likely not good for cooling properties of the PCB but I'm not concerned. It's working till I get my new module in.

norbert mcguirk

Checked my fpdm today. 2007 lariat. I be replaced every plug every coil pack. Ran a little better still not right for a year I've been fighting this truck. Ran across this article by chance. While trying to change starter. I checked my fpdm and to my happy surprise found mine was actually broken. Hope new one fixes issues. That starter I replaced ford engineers should be beat for that. The up 13mm bolt 1 out of three is ridiculous. To top it my wife has an 2007 expedition limited and having same problems. Same engine. Already replace a seized up rocker. Not very happy with ford. Heads up the wire loom in the driver's door the wires break. They break inside insulation hard to find until they finally break the insulation. I had 5 of them. Chinese CU.

prheath

redfishtd

Mine was intermittent and would shutdown engine and not restart. I didn't have torque pro then to see fuel pressure on rail .When water gets in there it can really act funny .If its corroded on back and not on standoffs-- replace .Dorman seems to be fine .

prheath

Thanks!

rjg426

I'm the OP, and my symptoms are in the initial post. It ran fine at cold start but then sputtered with no power shortly after, when it warmed up. But I'm sure there are many different symptoms when these things go bad. Maybe relevant to your question, is that some time after this problem was solved, the truck started to lose power and also misfire in the damp weather. The plugs had maybe 30K on them (last changed at a non-Ford dealer before I bought the truck used). I decided to change the plugs and coils (with the boots) with Motorcraft parts. That solved the problem. A few plugs were loose in the head and a few boots were in bad shape. The truck has been running great for a few years since.