Hey everyone, I haven't posted on here in a while. The last time I posted was when I had fuel delivery problems. I replaced the fuel pump on the rail and the fuel pump in the tank. I know it sounds crazy but look at my ordeal here.
https://www.ford-trucks.com/forums/1...s-in-my-x.html
Now the last week I noticed my truck had no pick up/acceleration. It seemed very sluggish. I checked the fuel pressure and I am getting 60psi at an idle, then 60 psi when I wrap the throttle in park. Then when I foot brake it and get on the throttle the fuel pressure drops to about 35 psi. My fuel pump on the rail has been sounding weird, like pressure is building up (it begins to strain) and then spins freely, then pressure builds back up and then spins freely again. It doesnt sound like it is under constant pressure.
I am on vacation right now in Virginia beach and drove from New Jersey like this. Trying to get around people when the truck doesnt want to accelerate is frustrating. I just wanted to pick some of your brains so when I do get home I can fix this problem. I'm hoping it's not my trans. Nothing seems like it is slipping so I don't thing it's my trans. Oh, the other thing is my fuel mileage has gone up as well. This is the only reason, why I think I have a fuel delivery problem again.

 

theres 2-fuel pumps,for the Ex?

Ever consider the Hutch mod?

 

Did you remove the gasoline fuel pump from the tank and install the correct diesel pickup assembly? Is it possible the pump in the tank has failed and your frame rail mounted pump is working overtime to suck fuel through that unit?

 

Yep, read your other thread and as soon as I saw the gas-engine pick-up in your tank I knew how to fix it. Then, it looks like you replaced it with another one just like it???

The gas engines in X's and Super Duty's have a fuel pump in the tank - 7.3/6.0 PSD's do not have a pump in the tank. Not sure what pressure/volume the gasser pump makes, but it could be a restriction slowly killing the PSD pump all along.

I don't see any reason to replace the whole assembly. Just extend the supply and return lines to the bottom of the tank. Be sure to add a pre-pump filter like the WIX 33972 - but I DO NOT recommend using a primary-type filter upstream of the pump like Guzzle did in his write-up.

 

SKY, did you write that wrong, or am i reading it wrong. "Upstream" of the pump, to me, means "after" the pump, which i agree since the fuelbowl filters' there, but i dont remember seeing Guzzle do that though..

 

If you are standing on the bank of a flowing river, "Upstream" is the direction from which the water comes.

Upstream of the pump is toward the tank from which the fuel comes.

Guzzle put a fine filter between tank and pump: upstream.

Most folk like to use a coarse filter/strainer/water separator before the pump and then a fine primary filter after the pump (downstream).

 

What Travis said!! ^^^

I'm gonna have to do another write-up, so I don't have to tell everyone I refer to this NOT to do that. IIRC, he ended up adding a pusher-pump before that filter to compensate for the obstruction... For A LOT more $$, he could have just used a gasser pick-up with pump built-in!!

The (correct) OE pumps don't like restriction 'upstream' - they push better than they pull. Even the massive FASS pumps with Honda starter-sized motors only want 150mic strainer in front of them.

 

Got back from VA Beach last night. Had some problems on the way home. The worst was every time I hit a traffic light I had no pick up and you could tell that the engine was starving for fuel because it was shaking like crazy. When I stopped to get some fuel cause I only had a quarter tank left I went and filled it up and that seemed to help but the power still wasn't there like I am used to. So I am going back through my fuel system once more and see what I can find. I plan on looking at the FPR today. I didn't want to mess with it down in VA beach, god for bid something went wrong there. I would have just had to make the vacation longer! LOL


To answer some of your questions, yes I considered the Hutch Mod, however I bought my Excursion back in 2003. I never made any modifications to the tank. At that point it was 3 years old when I got it and if you look at the date stamping on the "in tank" unit it matches the same date stamp on the door of 4/2000. So I replaced what was in there. At the time I was thinking it worked for 10-11 years without a problem so why change it. Needless to say is I am probably going to end up putting the proper in tank sending unit on mine or modify the one I have. A new unit is $300! Money I don't have right now. so I am about to head out to my garage and take a look at what I have going on. Til this day I still don't know why that in tank unit was in there and no one could explain to me why either. Maybe a mistake at the manufacturing plant?

 

Mine is doing the same thing on the fuel pressure drop, and I don't have a pump in the tank. On WOT runs, it drops to 39-40 psi, and on regular launches it drops to 48 psi (from 58). I have ruled out in tank restrictions, fuel filter and the water separator that came with the DI kit. Mine is not acting like it is starving for fuel...still runs very strong even while the pressure is dropped. So, am at a point where it is either the pump or the gauge. I doubt it is the gauge...it is new.

 

I bet you can figure out how to do that!! It's not rocket surgery. If you decide to use 'hose' in the tank, make sure its OK for immersion - some hose exteriors will fall apart under diesel.

Plug off the Frx and see if that helps. 40psi isn't hurting anything though.

 

Two things, what is a DI kit and what/where is the FRx?

I did install one of these...

Riffraff Diesel: Fuel Rail Crossover™

Maybe that eliminates what you were talking about.


Well, I just took my truck for a test ride and it feels much better. All I did was check power at the pump on the rail and power at the pump in the tank. The pump in the tank is not working. I partially dropped the tank, and checked power there and there was power at that connector. I pulled off the FRx and checked the spring (black) it was a little bent. I straightened it out. Now it seems like it has quite a bit more pep in its step. I still want to see what the fuel pressure is while driving. I will try to foot brake it and step on the throttle to see if the pressure still drops. I really have no other way to check the fuel pressure while driving. The hose that is connected to the fuel bowl isn't long enough to run it any where. Maybe I'll just have to make a new hose.

 

When I wrote DI kit, I meant the Strictly Diesel hutch mod kit. It comes with a Baldwin water separator that is installed before the pump. It is not causing the drop in fuel pressure for me, because I bypassed it and got the exact same drop on a test drive.

Jason, you think the RiffRaff FRx is causing the drop? I know dropping to 40 psi isn't "hurting anything" per se... I just don't need my pump to go out on the side of the road if it is the culprit and on the way out. I didn't put a fuel pressure gauge in until I got the FRx installed, so I don't really know what the pressure was doing under a load before the FRx. Before the FRx, I had monitored it for a bit with a mechanical gauge while revving in the driveway, and it held pressure fine then (53 psi). When I rev it in the driveway now, it holds pressure with my electronic sender & gauge. I only have a problem when under load it seems.

 

Well I foot braked it at 2400 RPM I'm at 20 PSI, at 2000 RPM I'm at 35 psi and at 1500 RPM I'm at 50 psi. At idle I'm at 64 psi. I don't know how that compares to what you have Nicmike.

 

Mine has a similar drop. Yours seems to be a little more extreme...mine only gets to 39 psi at 3000 rpm while rolling. No foot-braking here. As my RPMs rise, my pressure drops proportionally...just like yours.

 

How old is your pump? I just replaced mine with a Bosch like a year ago.