Safe To Use?

crash-harris

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When checking on the springs in the flywheel yesterday, I noticed what looked like a small filter just after the FSV. I thought it odd since the 7.3L has a filter on top of the engine and frame rail filters are normally bigger.

Turns out it is a switchable electric pump, I'm guessing to aid in starting. I've never seen a small on that looks like this and I'm wondering if it's safe to use to aid in startups until I can get to replacing seals on the fuel system. I don't want to damage the diaphragm on the lift pump by playing around with it.

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And if anyone recognizes it and could offer some specs on it, I'd welcome it.
 

IDIoit

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I would delete it.
makes no sense having it on just 1 tank
IMO its a hokey attempt to fix a bigger issue.
 

crash-harris

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I agree with that. The FSV is stuck on the rear tank. I'm only curious if it would be safe to use to bring fuel pressure back up before cold starts.

I do plan on doing a new fuel filter and return line kit with new o-rings and injector olives, but it may be a few months before I can get the parts/time to get it done.
 

snicklas

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Good golly I have never seen rust like that!

Welcome to the Midwest.......

The DOT loves their salt in the winter..... Unfortunately, there is a lot of stuff up here like that.... my 91 Jetta from Michigan is similar in shape on the bottom.....

Kroil / Blaster is your friend up here........
 

The Warden

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I agree with that. The FSV is stuck on the rear tank. I'm only curious if it would be safe to use to bring fuel pressure back up before cold starts.

I do plan on doing a new fuel filter and return line kit with new o-rings and injector olives, but it may be a few months before I can get the parts/time to get it done.
Fuel filter and return line kit are good ideas.

As to using the electric pump...if the mechanical lift pump is still plumbed in, running that electric pump is really not a good idea. I thought about doing something similar, but if the electric pump is putting pressure on the diaphragm on the mechanical lift pump, and that diaphragm fails, you will be filling the crankcase with fuel :shocked: if you want to run the electric lift pump, be prepared to run it full-time and bypass the mechanical pump ;Sweet
 

crash-harris

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Yup, lots of rust. Plus it came from Northern Ohio so it's s little worse.

I wouldn't run the electric pump while running the engine, just for a few seconds to reprime the fuel lines. I could hear it load up when I tested it, so once I hear it start to load I would shut it off and start cranking.

Not sure if it would be able to fuel the engine running all the time anyway.
 

fsmyth

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FWIW, I have been running mine like that since I got it.
Added a pump and in-line filters on the frame.
The filters are to catch any crap before it reaches the pump.
One on each tank, so I can see where a problem begins.
Band-aids until I can drop the tanks and clean them.
Pump on to prime or start, off while running. Mechanical pump
pulls fuel through it just fine when it is off. Either pump will
crush the element in the in-line filters when clogged :)
Makes getting the air out a LOT easier.
Also added a 10-micron filter in the line from the lift pump.
All of this stuff was added because: 1) that's what I do to
all diesels I get, and 2) because I had it on hand.
 

crash-harris

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I'm planning on getting another filter head for a wix 33005 filter that I can put on the frame rail since filters have a certain duty cycle for their advertised filtration ratings. Figure it'll catch some more crap before it gets to the lift pump and I can put a slightly better filter on it too. The head I'm looking at plumbs in with hose barbs.

I haven't really looked since I haven't gotten around to it yet, but does the line on the frame rail from the FSV to the lift pump converge, or stay seperate until the lift pump? If they converge, I'll put just one filter head on the frame rail. If seperate, I'll probably do 2 slightly cheaper ones that I can plumb in with hose barbs.
 

fsmyth

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Not sure I understand your question. The feed line doesn't "converge", unless someone
plumbed the electric pump in parallel with the mechanical pump. Bad idea, unless you
put check valves on both. The return lines DO converge. Different places for different
trucks/engines. Mine is used as a pusher - plumbed in-line immediately after the FSV.
The in-line filters are on the lines from the tanks to the FSV. I did have another at one
point between the FSV and the electric pump, but it got lost somewhere along the way.
All other filtering is done after the mechanical pump. The tighter weave needs pressure.
As an aside, I only filter the older diesels to ~10 microns. The later engines get 2-5.

I should add: use this setup with some common sense. Not all electric pumps will
allow you to pull fuel through them. Most of those are higher pressure (vane and gear
pumps). I check my oil level often - I would notice if my level was going UP instead of
down :) So, I don't worry too much about the diaphram. If it DOES begin to leak, I
will just bypass the mechanical pump, and run the electric pump constantly.
 
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icanfixall

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Our trucks have 4 lines going to anthe fuel switching valve but... Only 2 lines leaves the valve. I'm not seeing this electric pump installed BETWEEN the tank and said valve. You might try this. Remove the rubber line at the mechanical lift pump and attach it directly to the line going up to the standard fuel filter. then run the electric pump all the time. If it fails just reconnect the rubber line to the mechanical lift pump.. Easy peazy really.
 

crash-harris

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I just checked a labeled picture of the FSV since I'm states away from the truck at the moment, and did indeed see that there's just one send line from the valve to the pump. IDIoit mentioned "just on one tank", so I wasn't sure how different the send line was from the EFI gassers (maybe had 2), but just one, same thing, all good.

So in conclusion, I'm going to tie it into an unused switch in the cab to help with starting until I can get to reselling the fuel system. Although I'd love if I could cheaply connect an indicator light to it that would change brightness (like dim) when the pump starts pressurizing the lines to reduce the risk of damaging the mechanical pumps diaphragm. I'll just use it with my normal common sense and overly **** paranoia :D
 

fsmyth

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I just checked a labeled picture of the FSV since I'm states away from the truck at the moment, and did indeed see that there's just one send line from the valve to the pump. IDIoit mentioned "just on one tank", so I wasn't sure how different the send line was from the EFI gassers (maybe had 2), but just one, same thing, all good.

So in conclusion, I'm going to tie it into an unused switch in the cab to help with starting until I can get to reselling the fuel system. Although I'd love if I could cheaply connect an indicator light to it that would change brightness (like dim) when the pump starts pressurizing the lines to reduce the risk of damaging the mechanical pumps diaphragm. I'll just use it with my normal common sense and overly **** paranoia :D

Tip. Add a fuel pressure gauge. You will be glad you did ;)
 

dunk

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Good golly I have never seen rust like that!

Pretty common in the northeast. This is why every little task takes me forever. First you draw staws if you're gonna be fighting rusted fasteners, maybe a trip to hardware store for new fasters, drilling and tapping if you're real lucky, then disassemble everything, disassemble whatever is rusty that you can now get to, wire wheel/sandblast is all, prime, paint, etc... finish job you originally intended to do. If you intend to keep a vehicle for a long time you're constantly addressing rust issues before they become bigger issues.
 
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