Fuel line return routing with R&D rails

[TheRadBaron]

I’m rebuilding and modifying the entire fuel system on my ‘94 IDI-T.
I’ll be using an electric fuel pump and doing away with the engine mounted fuel filter.
I’m working on installing the billet fuel return rails from R&D and I’m not sure about the best way to route the lines. Here’s my first idea.

It’s been suggested that I need to use a check valve on the way back to the tank to prevent drainback, and that the brass 90 at the back of the engine on the drivers side has a check valve.

I’ve gotten some other opinions that suggest that the return system needs to be plumbed “in series” to allow all injectors to return properly. I don’t *think* this is the case but I could be wrong. I don’t remember the factory setup being plumbed that way and if it is necessary I can’t see what the optional fittings in the middle of the rails would be used for.
What do you guys think?
I’m trying to keep the hoses and fittings to a minimum for the sake of simplicity and less potential for leaks.

 

[franklin2]

How do you put a check in the return line? Wouldn't that stop the flow to the tank? So you turn the check around and now it allows fuel to return to the tank, but will not let the fuel from the tank flow to the engine in the return system. What good is that going to do?

I had an idea, have mentioned it a couple of times on here, but have never pursued it. If you had a electric solenoid valve rated for fuel and was 12v, what if you put that in the return line. Key on, valve is open. Key off valve is shut, and not letting fuel drain back to the tank.

The reason I never pursued it, it would really just be a big band aid. If your fuel system is in good shape, you do not need any checks or valves in the return system. But maybe if I get desperate and are having fuel drainback problems again, I can put a manual valve in the return line and see if that cures it, even though I have a leak somewhere. If it did, then possibly a hydraulic solenoid valve would work in the return line.

 

[TheRadBaron]

I think you’re right about the check valve. Someone said you needed one and I didn’t think too much about it.

 

[IDIBRONCO]

How do you put a check in the return line? Wouldn't that stop the flow to the tank? So you turn the check around and now it allows fuel to return to the tank, but will not let the fuel from the tank flow to the engine in the return system. What good is that going to do?

This is absolutely, 100% correct. Now you can install one in the rubber hose before the lift pump, if yours is still the mechanical style. Again, if your fuel system is in good shape, and you no longer have the return line coming off of the factory fuel filter, there really isn't a need for an anti drain back valve there either.

 

[DirtyWood]

I would ask R&D what the preferred routing is since it's their product. I don't have the fuel rails but I did buy the billet aluminum caps and have them routed in a loop basically. #7 connects to #8 through the return tee, and #1 connects to #2 with the IP return teed into it. Zero problems so far. I think the idea is to get away from deadheading the fuel at any point in the system.

 

[DougBoy66]

I have the fuel rails from R&D and have it set up almost exactly as you have drawn. I have eliminated the return to the filter and the return to the IP is on the driver side front instead of passenger and use the center ports to connect the two rails with the rear driver side of the rail with a short hose going to the brass block going to the return to tank line. I do not have a drain back or air intrusion problem...........so far

 

[DougBoy66]

Also, watch R&D video on installing the fuel rails. The injectors need to be installed into the rails before you install them into the heads. Install them by turning each injector a little at a time and at an even amount so that they all four go in at about the same pace. Maybe a half turn each until they are all the way inserted. If you try to install the rails onto the pre installed injectors you will fight them and cut the o-rings and fill your work area with an unimaginable amount of curse word (if you are so inclined to use them, if you are not, you may start to at this point). I also used the ends of some old leaky injector lines, cut off with about an inch of the end of the line still in the fitting and used those to keep the injectors from slipping out of the rails when I installed them. I will see if I have a picture of them during the install and add it if I do

 

[DougBoy66]

Here is what I was talking about for set up to install

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[TheRadBaron]

Here is what I was talking about for set up to install

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Interesting idea. I didn’t go that route but I did leave the injectors slightly loose when I installed the rails. I used some grease on the bores and the o-rings and the rails went into position easily and I don’t think any o-rings were damaged.
I guess I’ll find out when I start the engine hopefully some time in the next few weeks.

 

[DougBoy66]

Hopefully that works, I did not have it work out that way. I did all the ways you did but always ended up nicking a o-ring. One thing for sure you will find out pretty quickly if ya did or didn't.