Fuel Injection Questions

I am still working on my Ford 5.0 EFI swap. Free time for wrench turning has been in extremely short supply. The engine is now bolted firmly into it's new home thanks to some MORE Bombproof motor mounts, and the installation was much easier than anticipated.

My current problem to resolve is the routing of the fuel return line to the tank. I just finished pulling the factory tank and fuel lines in preperation of installing a new poly tank,lines, high pressure electronic fuel pump & filter. I have been trying to figure out the best way of running the return line to the tank.

I noticed while comparing the old and new fuel sending units that the second port (not the pick-up tube) on the factory setup is capped off. Can I use this to return fuel to the tank safely or is it too close to the electrics in the sending unit? This would be much easier than drilling the new tank for a fitting. How about adding a bit of fuel line to it as an extension?

Alternately, how about using one of the vent tubes on the drivers side of the tank?
I had planned on plugging these anyway to prevent fuel spilling at extreme angles or in the event of a roll-over. Im open to suggestions.

Also, does anyone know which is the feed line and which is the return line on the 5.0 EFI ?(not the Mustang HO, but the regular car/truck engine) There is a line on the drivers side as well as the passengers side, with a schraeder valve on the passengers side of the fuel rail.

 

I have used the vent tubes on the side of the tank for a return. Works fine. I stayed away from the line in the float assembly, just because I didn't want splashing near my pick-up tube.

 

Thanks,
I should be getting started on plumbing the fuel system in a couple weekends, as I will be on duty this weekend.

I finally have a few photos loaded, so hope you like seeing how the (verly long-term) project is coming.

 

Grab a Mustang 5.0 book.
That will tell you which is inlet and out (return) lines on the fuel rails.

also maybe give you an idea where to hook up the return at the tank.:hurrican:

 

Wouldn't the schraeder valve be where you monitor fuel pressure. Making it the supply line.

 

Yup. Unfortunately not all Fords have those....
You can usually tell supply and return by looking at the size of tube/fittings. Normally the smalll is return and larger is supply. Nickmil

 

The lines are both the same size, with the schraeder valve being on the passenger side front and the factory pressure regulator on the drivers side near the firewall. I have been told by guys on 5.0Tech.com that the line closest to the regulator is the feed, so Im going with that and hoping for the best. As this is a regulas car/truck EFI motor instead of the HO 5.0 Mustang notor they realy didnt have a lot of advice either.

The rest of the fuel supply parts should be in by this weekend, so as soon as the chassis wiring harness is installed the fuel supply system comes next followed by the engine/EFI harness. Thanks for the advice and help.

BTW, from the pics whay do ya think of those M.O.R.E. Bombproof motor mounts?? I was very impressed with them. The physical fit is far better than I thought with the exception of the clutch slave-cylinder, brake line junction block & exhaust clearance on the drivers side.

 

That exhaust really is in a heck of a place. Couldn't you find any manifolds or headers that had a better exit?

 

On my 5.0 engine, the supply line is 3/8 and the return is 5/16. I used -6 and-8 AN adapters and ran Aeroquip low pressure hose (250psi) and Russel's barbed AN fittings to plumb the system. I removed the small vent tube from the sender and drilled out the sender to fit the correct size tube for the return line (solder the new tube to the sender flange). I used tube long enough to extend to the bottom of the tank (about the same length as the pickup tube) and secured the return tube to the supply tube on inside the tank(tie the tubes together).

The return should be the one nearest the regulator. The supply side pressurizes the entire fuel rail and the regulator passes the excess fuel back to the tank.

The engine you have, or at least the intake and fuel rail assembly, was never used on trucks. The truck intake assembly is a lot different. The style you have is car only, and it's pretty much identical to the Mustang HO setup except for the upper intake and the injectors themselves.

 

Unfortunately Mustang type headders have a large collector (over3 inches diameter) leaving no clearance for the clutch slave cylinder,and street-rod type headders direct right on top of the motor mounts. Right now priority is getting it running, then I'll rout the exhaust and fix the little things.

 

I had thought of the possibility of extending the vent tube on the sender as a return line. The local Ford Dealership shop manager gave me the info about the engine being the car/truck version, but as even he wasnt able to identify the feed from return line, guess I shouldnt be counting on the accuracy of his info.

AFAIK the EFI 5.0 and the HO 5.0 differed in intake (HO had longer runners), cam and injector size. for a difference of 15 to 20 hp.

Thanks for the info about identifing the feed line, will help a lot.

Either way ,,,free time permitting it should be running soon.

 

I was noticing the oil filter, can that come off okay ?
oh, and the mounts look good

 

Just enough room for it to come off with anout half an inch to spare, although it got banged up a bit during the engine install ( I left it on to protect the threads from damage). Might go with a remote filter mount in the future sometime. I will be replacing the brake lines with ones that fit better (possibly braided stainless) once I relocate the junction block to get it away from the exhaust and clutch slave cylinder.

All in all I'd say the SB Ford motor is a great fit ans mechanically an easy swap,,,even better than the SB Chevy swaps I have seen and done in the past (I am a Chevy guy). The MORE mounts,,although pricey, made the install very easy. If this was a carburated engine it would have already been running, but I really want the dependability of FI , so thats why it's taking a bit longer. In the long run Im sure I'll be happy I took the extra effort.

 

The return line is closest to the fuel pressure regulator, it regulates the amount of pressure to bleed off back to the tank.

You can use the extra port on the sending unit if you want to. My replacement sending unit allready had an extra port and thats what I used. No problems for as long as i had the stock tank. It really doesn't matter as long as the fuel can get back to the tank.

I'd caution you about doing to much spray painting before the engines running though. You don't want to spray paint over all the wires or connectors in case you need to rewire or trouble shoot the fuel injection system latter on in your swap. Had a jeep on the rubicon we had a heck of a time figure out a fuel pump issue because all the wires were painted gray. Just an FYI not raggin on ya though. Looks good otherwise.

Kevo

 

Since I am using a new harness I cut off the existing wiring, leaving the connectors in place to protect the connectors from overspray. Those without covers got covered in duct-tape. All the painting was done on the engine prior to installation, and I wound up having to clean,strip and repaint the inside of the firewall because the old clutch master cylinder leaked fluid all over it.

Thanks for the info on the return for the FI system. depending on my work schedule it should be running by late spring (or sooner).