New Lift, Still Biting, Splash of Air

[Big T]

If you're interested in bypassing the stock FSU, I installed this draw straw kit on my truck. Have yet to use it as the IP died shortly thereafter and truck has been parallel parked ever since, but I was personally excited to get away from the stock setup

AirDog | 901-01-0351-QC | Suction Tube Kit (Draw Straw)

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airdogliftpumps.com

I drilled a hole for the rubber grommet behind the tank FSU and made my own 1/2" fuel line using NPT and -AN fittings instead of the supplied quick connect ones as I just don't trust them.

Bonus of this setup is you can use the original feed line as another return port if you ever install a fuel pressure regulator that needs a return line

I know you're not in salt country but I can't stand how the factory fittings always freeze up on the steel lines and how it's a stupid uncommon fitting. I know Leroy sells fittings to adapt to barbs but at the end of the day you're still sucking fuel from the tank from a 3/8" fitting and then into a 1/2" line. How much of a restriction this creates leading to sucking in air elsewhere I don't know, but the draw straw kit linked above seemed like the easiest route in terms of fab skills (drill a hole, cut a plastic tube to length) and time (took a few minutes when I swapped tanks last fall)

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If the ordered feed line does not cure the problem, I may have to go this route. I still may try to drop the tank and find the seal for the feed line this week to see if that fixes the problem. So haven't thrown in the towel just yet.

 

[Big T]

OK, the best goes on. Drained and dropped the fuel tank. Looks like a plume of fuel coming from the feed line:



The o-ring seals are hard and pretty beat up. I will try to source them locally at NAPA tomorrow.

 

[Will L.]

Try to get ones rated for methanol

 

[Big T]

Try to get ones rated for methanol

I’ll try, but will be happy with Viton

 

[jrsavoie]

I’ll try, but will be happy with Viton

I thought Viton were the ones rated for methanol

 

[Will L.]

Viton is rated excellent against ethanol, fair for methanol. You should get a decade, maybe 2 from it.

 

[jrsavoie]

Viton is rated excellent against ethanol, fair for methanol. You should get a decade, maybe 2 from it.

That's enough for me!

 

[Big T]

Y’all think I’ve found the problem?

 

[Will L.]

Highly likely. A better lift pump will cause more aeration.

 

[Big T]

Highly likely. A better lift pump will cause more aeration.

 

[dbrannon79]

be sure to check the rubber lines that connect to the tank sender too while it's down. it would be nice if the lines were long enough to set the tank on the ground, connect it all up and try.

Though you could pop the sender out, check the sock and tank condition too while your in there, set the sender in a open can of diesel with it all connected for testing before reinstalling the tank.

 

[Will L.]

I would rip out that sock. Thats what replaceable prefilters are for

 

[Big T]

be sure to check the rubber lines that connect to the tank sender too while it's down. it would be nice if the lines were long enough to set the tank on the ground, connect it all up and try.

Though you could pop the sender out, check the sock and tank condition too while your in there, set the sender in an open can of diesel with it all connected for testing before reinstalling the tank.

Right now I want to eliminate the air intrusion and get it running properly. If it gets there, I will reinstall the pre-filter and see how it runs. Then I have a new tank and feeder line coming. I will also order a new return line. When I finally have all of those, I will inspect the sock on the sender. I will note that I did replace the sender at some point after I bought the truck in 2010. It’s probably been in there for 10 years.

Note I typically ship all the parts to Montana to avoid sales tax. If the truck can be driven to SoCal this upcoming weekend, my wife will eventually bring them down in her 4Runner and I will send her back up with a load of split rail cedar fence posts which I have finally sourced. If not then I will deal with it at our Montana home on another trip up.

 

[Big T]

Changed the feeder and return seals at the fuel sender unit. Took a bit to prime, but putting back about 10 gallons of fuel fixed that. Took it on a 4 mile drive and it is now running smooth. Will do some more test drives and if all is well, I will re-install the pre-filter.

 

[Big T]

Changed the feeder and return seals at the fuel sender unit. Took a bit to prime, but putting back about 10 gallons of fuel fixed that. Took it on a 4 mile drive and it is now running smooth. Will do some more test drives and if all is well, I will re-install the pre-filter.

Drove the Suburban into Missoula to get a new floor jack at Harbor Freight and more engine degreaser at Home Depot. Took the long way home down Mullan to Kona Bridge and McClay Flats, back to 93. Put a total of 68 trouble free miles on it today. It's back to driving like a beast.

I will re-install the pre-filter in the am and may consider installing the pressure gauge, then I go fishing.

 

[Big T]

Re-installed the pre-filter and all is good. No fuel leaks and no longer sucking air.

 

[3500GMC]

Re-installed the pre-filter and all is good. No fuel leaks and no longer sucking air.

Good deal and thanks for checking back on the 'fix'.

 

[Big T]

I would rip out that sock. Thats what replaceable prefilters are for

Here’s why I would not rip out the sock: in addition to providing some pre-filtering, it is there to provide greater surface area so that a leaf or similar cannot be sucked into the pick-up tube end and obstruct it.

 

[Big T]

Good deal and thanks for checking back on the 'fix'.

I took it fishing and off-road yesterday and it performed remarkably well. It does feel like it gain some power. I’ve now driven it about 200 miles and got the tank down from just over half full to just under 1/4 full, which will make life easier when I come up in October and replace the tank plus feed and return lines.

 

[MrMarty51]

That is some mighty good news about getting the truck back to running like it should.
I have not been in the forum much lately but when I did make it in, without dozing at the keyboard, I was following this thread.
And now it feels like I could close my eyes and take a nap, already this morning.