fuel line routing

ZGjethro · Post by **ZGjethro** » Tue Apr 13, 2010 3:23 pm

I am replacing my fuel lines, which are a hodge podge mess of old steel armored lines, hose clamps and rubber fuel hose with a few leaks. I have an electric fuel pump and fuel filter just in front of the tank and will be eliminating the original fuel filter. I am looking to run 5/16 flexible fuel injection hose from the pump to my pressure regulator on the inside of the front right fender well. Does the original path work well or is it better to cross over behind the engine and follow the right frame member. It will be difficult to fasten the line under the radiator without removing it. Just wondering if anyone has any advice. Thanks, John

rixm37 · Post by **rixm37** » Tue Apr 13, 2010 4:27 pm

I just replaced mine with the engine and radiator in. I stuck to the original path under radiator. There should be a couple of clips bolted to the cross member under it to hold the line in position. It took some arm twisting and tweaking, but I got it in there without a big hassle. It is now out of the way and uses all the original hold downs on the left frame rail.

ZGjethro · Post by **ZGjethro** » Tue Apr 13, 2010 9:25 pm

rixm37, thanks for the tip. I did not see any fasteners under my radiator, but I will look closer. I would rather have it in the factory clips than try to fasten it myself.

ZGjethro · Post by **ZGjethro** » Sun Apr 18, 2010 7:28 am

So I ended up buying 25' of Goodyear fuel injection hose. That stuff is pricey! I ran it from my electric fuel pump, through the hollow frame cross member, through four small holes in some frame brackets and then followed the speedometer cable into the engine compartment. The fuel pressure regulator is on the right fender so it was pretty direct. I now have no fuel shut off valve, but the regulator is higher than the tank, so there should be no flow if I disconnect it on flat ground or in my garage. The whole reason for replacing the line was a leaking shutoff and leaking rubber lines at the fuel filter. I decided to remove all those parts. I have two fuel filters, one at the pump and one at the carb. I think it will work well

cuz · Post by **cuz** » Sun Apr 18, 2010 8:26 am

Make sure where the hose passes through steel framework that it is immobilized with a clamp or grommet to prevent it chaffing against the steel.

MSeriesRebuild · Post by **MSeriesRebuild** » Sun Apr 18, 2010 11:53 am

It isn't a good idea to use hose where hose isn't needed. It can get cut, burned easily, damaged by unsightly stuff as passed through frame members and a host of other issues. It will suffer damage over time from wear caused by a constant pulsating fuel pump. You may or may not see this action going on, but rest assured it is there. The best fix is to use steel brake line tubing as the main line, incorporating hoses at either end where it is necessary as a flexible member of the system.

Your choice of location for the pressure regulator is not ideal either, you will be better served locating it away from engine heat. I'm assuming from your posting that your new hose is routed along the right side frame rail as you mentioned a similar route of the speedo cable. If my assumption is correct, that's another bad idea as it runs near the exhaust pipe routing. You will be running a risk of being aggrevated by vapor locking in hot weather. Worse yet is the possible occuring tiny hole in the hose that very possibly would spray gas directly onto a hot exhaust system. I just can't see taking risk like this. As a safety factor alone, the line should be routed as far away from exhaust components as possible. There was a reason why the original route was inside the left frame rail and across the back side of the front cross member, this is an easy route to access, and the safest you can follow.

I'd hate to read a futue post explaining how your truck was burned down following a fuel leak and explosion, worse yet would be reading a post written by another telling us that you are no longer with us as a result.

ZGjethro · Post by **ZGjethro** » Mon Apr 19, 2010 5:46 pm

Thanks for the advice Charles. Given that my electric fuel pump is on the left side of the hollow frame cross member, where is a good place for the pressure regulator to be mounted. If it is not in the engine bay, is next to the fuel pump a good spot? I was hoping to avoid a bunch of junctions in the fuel line, as the leaks I had were at the fuel shutoff and at the fuel filter lines. I will rethink my routing.

MSeriesRebuild · Post by **MSeriesRebuild** » Mon Apr 19, 2010 7:44 pm

ZGjethro wrote:Thanks for the advice Charles. Given that my electric fuel pump is on the left side of the hollow frame cross member, where is a good place for the pressure regulator to be mounted. If it is not in the engine bay, is next to the fuel pump a good spot? I was hoping to avoid a bunch of junctions in the fuel line, as the leaks I had were at the fuel shutoff and at the fuel filter lines. I will rethink my routing.

Regulator mounting in the engine bay isn't all bad, I would suggest somewhere on the driver's side as far away from the engine as possible. This will keep it away from the larger heat sources. A location just ahead of the pump is also good. Routing the line across the back of the front cross member keeps it below the engine and further from heat. The use of metal tubing with fiberglass insulation where it crosses over the manifold going to the carb works well.

Master Yota · Post by **Master Yota** » Mon Apr 19, 2010 10:39 pm

Follow the instructions on the regulator - they usually indicate that for accurate regulation the line needs to be straight and level for several inches on either side of the regulator.

Something to consider - rubber hose does not transfer heat like steel tubing does. Vapor lock is more common with steel tubing when close to a heat source. Rubber hose usually softens or melts, but is generally a better insulator at keeping the heat at bay. So long as you have 3" or more of clearance between the hose and heat source, it will be ok. Heat shields work very well too, or even fiberglass exhaust wrap as a last resort.

Routing is critical with rubber hose as it will chafe at every oportunity. The black plastic split wire loom makes for a good protector at rub spots, and the hose should be secured at a minimum of every 12" or so...

Good luck.

ZGjethro · Post by **ZGjethro** » Tue Apr 20, 2010 5:13 pm

New idea. I will use the factory lines to the factory fuel filter location. They do not leak, yet. Since I do not need it, I will remove the filter and install the regulator there. Is there any reason I should not run a flexible line across the top of the engine to the carb. This way I would not have to run a steel line under the radiator like the original routing (I am not using the mechanical pump and will be removing and plating it off) and I could avoid having a fuel line right next to the exhaust manifold, which is way hotter than the top of the engine head. I could fasten the line to the oil filler breather tube. Give me your opinions. I changed my first install based on what opinions I got here. John

cuz · Post by **cuz** » Tue Apr 20, 2010 7:22 pm

John, Run a steel tube across and clamped to the firewall. Then use a short hose from the passenger side firewall to the carb. While you are forming this new tube and fittings perhaps you should install a "T" between the hose and the steel tube and cap the extra port to be used later when you want to troubleshoot the fuel delivery you will have a convenient connection available for a pressure gage.

hbb · Post by **hbb** » Tue Apr 20, 2010 7:46 pm

cuz

Great Idea on the tee for later diagnosis, if only would have had one awhile ago that would have been very convenient and saved some time.
hb

ZGjethro · Post by **ZGjethro** » Tue Apr 20, 2010 8:22 pm

I currently have a pressure gauge on one of the two outputs of the fuel pressure regulator. Would I gain any accuracy having it nearer the carb. The pressure in a fluid should be the same throughout the system.

I like the idea of running a steel line along the firewall. Would you use a steel line from the carb bent in a 180 degree arc to avoid kinking a hose? A piece of flexible hose from the firewall to this tube would take care of any movement or vibration.

cuz · Post by **cuz** » Tue Apr 20, 2010 9:36 pm

No need if you already have a gage in the system.

SierraM37 · Post by **SierraM37** » Wed Apr 21, 2010 4:22 am

I R&R'd all my brake and fuel lines this summer as part of my frame off. I stuck with the original routing along the drivers side of the frame and am not using a fuel pump at present. I did not want to re use the original lines as they are not that expensive to replace and I won't ever have to worry about them. Got to get a new bending tool to add to the tool box as well.

The original routing on the cross member under the radiator made the most practical sense as it is behind the member shielding it from objects that might fly in from the front. There are holes in the member that straps are secured to and I took off from steel to rubber right above the right front brake line bracket to the fuel pump and then rubber from pump to carb. Keep's it looking stock and as recommended, away from the exhaust system.

I also stuck with armor wrapped on the brakes but did not on the fuel line.