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HELP installing electric fuel pump
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HELP installing electric fuel pump
I have read and been told that replacing the mechanical lift pump with an electric fuel pump would be a great idea for my ageing 1983 F250 6.9 IDI. I have run a new fuel line from the filter housing back to the brand new (and tested) fuel pump (5-7PSI 30 gal/min). Wired in a relay with a fuse even! Quite the luxury for this old farm truck :-) The issue I am having is that I can pull fuel from a jerry can but I cannot pull fuel from the tank. I am within 2 inches of the fuel selector valve (which work fine) but I cannot draw fuel at all. I am totally mystified. I can pull fuel through 10' of 5/16" fuel line but I can pull it through 2" of original line that worked at the start of the day? Any help or even a direction to go in would be VERY helpful. I need this old girl running in the next few days to go and get hay and I am at my wits end.
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From: Virginia
Are you positive the valve is working? If you have plenty of fuel in the tank, then I think I would bypass the valve for the time being. They do not have a very good reliability record. Of course you would need to splice in two lines, the supply and the return lines.
If that doesn't work, or you are positive the valve is ok, then you will have to pull the tank. I think I would bypass the valve before I dropped the tank.
If that doesn't work, or you are positive the valve is ok, then you will have to pull the tank. I think I would bypass the valve before I dropped the tank.
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The FSV was working literally this morning. I can also hear it switch when I have my wife flip the switch from front to rear to front. I traced the line from the water separator back to the FSV and I know I am on the right line.
Should it be possible for me to "back flush" the fuel supply line? I hooked up a section of line to it through a hose barb union and it wouldn't take fuel that way back to tank, I assumed there would be a check valve there but i was desperate and trying to see if I just needed to prime the line.
Should it be possible for me to "back flush" the fuel supply line? I hooked up a section of line to it through a hose barb union and it wouldn't take fuel that way back to tank, I assumed there would be a check valve there but i was desperate and trying to see if I just needed to prime the line.
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From: Virginia
No check in the suction line at the tank. Do you have plenty of fuel? The pickup screen on the ending of the sending units on these diesels likes to break off. It's called the "shower head" because that is what it looks like. When that breaks off, you can't go much below 1/4 tank before you run out of fuel. Mine's broken off on my rear tank and I have run out of fuel once with it.
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I am not saying that you are wrong with the FSV gone bad, I am just saying that it is a ******* and a half to bypass it with where the truck is currently and I find it funny/fishy/unlikely that the FSV would just totally fail as soon as I looked it. I mean I get that stuff fails but it just seems weird that it would fail RIGHT when I put in an electric fuel pump, you know what I mean?
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From: Virginia
Well, you are going to have to do some sort of testing. I think what I would do is take the fuel line off the input to the valve, which ever tank you have selected, and put your line and jerry can on the other side of the valve. If it pulls fuel from the jerry can, through the valve, and the engine runs, then you know the valve is good, there is something wrong from there to the tank.
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Yeah, I was afraid you were going to say that. I was hoping that there was some stupid thing I overlooked. I will head into town tomorrow morning and grab some hose barb unions so I can test further.
Can't blame me for hoping right? :-P
Can't blame me for hoping right? :-P
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From: Virginia
You are using the original fuel line setup with the quick connect fittings? When you take the quick connect fitting off, you are left with a plastic piece with a bump on it correct? I have just slid rubber line up on that piece with a hose clamp before. Should be good enough for a test. And then just stick the line down in the gas can. I am assuming the fuel from the can will just return to one of the tanks, I wouldn't think you would need to mess with the return line.
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@Franklin2 , yeah I agree. I will no bother with the return line right away, I just need diesel to flow right now. LOL! I will get at it again tomorrow and if I have to run on only one tank for awhile so be it. While this truck is one of the reasons why I can keep my farm running this truck is very short haul so I would be fine with one tank, I just like having two :-)
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The more I think about it the more I am convinced that the spool or solenoid or whatever you want to call it is stuck. I say this because the engine has been acting like it was starving for fuel under load of a week or so. I also say thins because I SHOULD be able to back feed fuel into the tank through the FSV. so I tomorrow I will bypass the FSV and remove it from the truck. I will try to take it apart and see what is what. Worst case senario I will be runnign on the front tank only for awhile, there are worse things in the world I guess.
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From: Angier, NC
So you have this new pump up front after the 2 tanks, the FSV and a water filter and wonder why it will not pull fuel?
It's because electric fuel pumps push fuel not pull fuel.
Then you want to pull a thicker liquid thru all that stuff?
Not going to happen as you found out.
Electric pumps need to be mounted as close to the tank(s) and below fuel level as can be.
Dave ----
It's because electric fuel pumps push fuel not pull fuel.
Then you want to pull a thicker liquid thru all that stuff?
Not going to happen as you found out.
Electric pumps need to be mounted as close to the tank(s) and below fuel level as can be.
Dave ----
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From: Virginia
Don't worry. We had a f350 dump truck with a 6.9 in it. It had one of those little square fuel pumps that sit there and make a clicking noise, and someone had mounted it way up on the pass side inner fender in the engine compartment. It never gave us any trouble up there, it always had a good fuel supply. I would not have thought so myself, but why mess with success. And it was a nice protected place to put it not very far away from the fuel filter.
By the way, the original thread starter mentioned a water separator. The older trucks had a water separator and then the fuel filter on the engine. Everyone bypasses that original water separator, they are bad for leaking air and letting the fuel drain back to the tank, making it hard to start. If you have some sort of aftermarket water separator, then that could probably stay in place.
By the way, the original thread starter mentioned a water separator. The older trucks had a water separator and then the fuel filter on the engine. Everyone bypasses that original water separator, they are bad for leaking air and letting the fuel drain back to the tank, making it hard to start. If you have some sort of aftermarket water separator, then that could probably stay in place.
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So today I pulled out the FSV and just plumbed the electric pump to the feed side of the tank and ran the return back to the tank. I then switched the relay and I got fuel in very short order. I purged the air and the truck started right up and ran great! No more random stumbles at idle or weird random surges under load. I will probably take the FSV apart one of these days to see if I can get it to work again. Upon my VERY quick look at it today it appears that the spool valve or whatever it uses is jammed between positions and that is why I couldn't back flow (or draw) fuel through it.
I thank you for your time, efforts and guidance to get me to a working solution.
I thank you for your time, efforts and guidance to get me to a working solution.
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