Fuel delivery system identification

[Jdcline54]

Hey guys I'm just wondering if anybody has any tips on identifying what type of fuel delivery system I have on my 03 5.4 l.

I briefly glanced at the description and operation on all data which showed three different types. From what I can see under the hood it looks to be a returnless system. That being said there is a vacuum operated fuel pressure regulator on the injector fuel rails. So that doesn't seem to make a lot of sense.

So I guess what I'm asking, is there a clear easy way to identify my fuel system type?
if not it's not a big deal. I'm going to go back up to the school tomorrow and read about it on all data again, but I have a lot of thoughts going on in my head about what's potentially wrong with my fuel system and really I just don't want to wait until tomorrow. LOL

 

[dwm1294]

I fixed all my problems with my expedition 2003, it was clogged catalitic converters replaced and all codes went away and it's running like brand new

Sent from my Moto G (4) using Tapatalk

 

[Jdcline54]

I fixed all my problems with my expedition 2003, it was clogged catalitic converters replaced and all codes went away and it's running like brand new

Sent from my Moto G (4) using Tapatalk

I don't have any codes. cats are clear, O2's are good. just have some odd fuel pressure readings that suggest the fuel pump is weak. but without knowing how the rest of the fuel delivery system works it's hard to nail down if this is an issue or not, and if it is, what exactly it is.

 

[dwm1294]

Have you tried a fuel pressure gauge to see if your fuel pump is putting out the appropriate fuel pressure? Heck until I found out my cats were clogged I was scratching my head because I was getting different codes after I would think I was fixing one and another would fall in its place. All these codes and stuff end up feeding off the other and have people running in circles. I had a old school mechanic told me to disconnect the exhaust at the flange of the manifold and if it runs rite after that then that's the problem. Heck he had just put a high dollar reader diagnostic unit on it and he said he still couldn't tell me for sure what to do but gave me that suggestion off the symptoms I gave him

Sent from my Moto G (4) using Tapatalk

 

[Jdcline54]

Yeah I put the fuel pressure gauge on it. Spec is 55 with the key on engine off. And 55 with the engine running. I get 35 with key on engine off and 55 with key on engine running. But when the engine is accelerated the pressure drops.

After putting an oscilloscope on the power line for the fuel pump a pretty well determined that the pump is pretty weak probably due to the impeller. But like I said until you have the whole picture it's hard to say without a doubt what the problem could be

 

[John Stephan]

Internal, non-serviceable relay in passenger footwell.
Duty cycle controlled module inside drivers frame rail next to spare, behind axle.
Fuel pump
Fuel pressure regulator

Sent from my SM-G950U using Tapatalk

 

[John Stephan]

The control module has a nasty habit of galvanic corrosion between the aluminum housing and steel frame. In salty climates they are doomed. Updated units gap the module away from the frame.

Sent from my SM-G950U using Tapatalk

 

[Jdcline54]

The control module has a nasty habit of galvanic corrosion between the aluminum housing and steel frame. In salty climates they are doomed. Updated units gap the module away from the frame.

Sent from my SM-G950U using Tapatalk

thanks for the info that's exactly what I was looking for. about the salty climates, that's a great bit of info! I live in Eastern Utah, which isn't really what you would call a salty climate, but they salt the roads to death in the winter time here. although at this point in time I don't think I have that issue, its great to know that it could be an issue. that's something that would be very easy to over look. and since i'm likely going to be in there soon anyhow, I will probably go ahead and do some preventative work on it.

thanks again!

 

[Hamfisted]

Yours is an '03, you don't have that fuel regulator module back there. Your fuel pump is controlled by the PCM and a crappy little fuel pump relay in the fusebox there in the passenger side footwell. Just due to age your fuel pump can be getting worn out. No harm in putting in a new one and eliminating that possibility from becoming an issue later. There is a fuel pressure check valve in the fuel pump assembly, and that helps retain static pressure in the fuel line so you'll get quick easy startups. If you put a fuel pressure gauge on the fuel rail you should see fuel pressure stabilize at 20-30 psi after ignition key is shut off. It should hold that pressure. If it drops to zero the check valve in the fuel pump assembly is bad and the only way to fix it it replace the assembly.

thanks for the info that's exactly what I was looking for. about the salty climates, that's a great bit of info! I live in Eastern Utah, which isn't really what you would call a salty climate, but they salt the roads to death in the winter time here. although at this point in time I don't think I have that issue, its great to know that it could be an issue. that's something that would be very easy to over look. and since i'm likely going to be in there soon anyhow, I will probably go ahead and do some preventative work on it.

thanks again!