Yesterday I removed my fuel tank thinking that I'd need to clean it out because I had a stumble from my engine.

That's how I did it and what I found out.

Emptying the tank is really easy- you need about 6 ft of 10mm id fuel hose and 2 pcs of test wire about 5 ft each.

Push the fuel hose over the drain hose of the fuel filter, unplug the lift pump plug and using the test wires apply 12V from the battery to the fuel pump. With the fuel drain open you can empty the tank into canisters that way.
I found that my truck did aerate the fuel like mad while doing this. (You can see the air bubbles in the transparent hose of the fuel filter drain and the foamy stuff going into the canister.
When the tank is empty disconnect the wires.

Remove the hose clamps for the fuel filler on the tank, spray the region with silicone spray and pry a little with a screwdriver to loosen the hoses. Slide the hose clamps up the hoses as far as possible.

Hand over the frame rail unplug the fuel sender connector.

Repeat with fuel lines and go crazy because the rusted quick connects won't come off. Resort to violence and cut them with a knife.

Loosen and remove fuel tank holding bracket bolts, catch tank by hand, tilt it to the side and slide it out from beneath the truck. (Doing this in the snow helps... )

Take a look at the top of the module- there are two lines that feature quick-connects, the smaller one is the return.
Both of them were rusted through, no wonder there is some air getting in.

Pulling the module is easy- take a blunt chisel to the ring that holds it in and after one or two taps you can turn the ring by hand- remove ring and slip module out. (Take care not to bend fuel level sender)

In the module the suction line makes a kind of a spiral.- At one point of that spiral it touches the point of a screw, naturally there is a hole in the line- another source for these little bubbles.

Due to the stock part with the feed and return connectors being completely rusty and because I already have a holley blue in the frame rail we decided to do something nasty- we removed the whole metal cap with the connectors and the lines on the inside of the module. Now we attached a 10mm id fuel hose to the point where the stock feed line starts it's climb to the connector part. Using some different sizes of fuel hose (each about 2,5" long) we built up enough rubber to get to the same diameter that the cap with connectors had- adding 2 hose clamps keeps it together (Using the stock rubber gasket) -leave the 10mm fuel hose long, don't cut it yet.

For the return line you can use about 8" of 8mm id fuel hose- it will slide right over the stock return line plastic part (we cut the quick connect before) and it will also fit on the 5/16" auxiliary connector in the module. The straw of the aux connector can be turned to end at the same place as the stock return.

Install module in the tank, install tank and route the 10mm feed hose to the fuel pump.

Now I've got a suction line to my lift pump where the minimum id is 9 mm , no kinks and it's made completely out of rubber fuel hose. No more corroding fuel tank quick connects.

Fill tank from canisters, using the method to empty the tank pump fuel into canister again until the air is purged, be glad that there are no more bubbles and remove the fuel hose, test cables and close the drain valve.

Start engine and smile. (Idle is a good bit smoother than before)

Materials used: some hose clamps, 6ft rubber fuel hose 10mm, less than 1ft rubber fuel hose 8mm , some scraps of other fuel hose material.

I think that the advantages of doing it this way over a draw straw etc are that you keep the in tank de-aerator and strainer functional, the catch tank for running low fuel level too, and you avoid the corrosion issues of the stock setup for cheap. The only downside is that you lose the aux fuel connector to use for an espar heater or a genset.

I couldn't take any pics because my cam was frozen and it was a kind of roadside repair. (10 F and windy by the side of a stream)


AlpineRAM

 

Good post and good fixes, all - however, there must be some kind of Negative Commendation Award for having almost all of the failures associated with that tank module - there is only one other: where the tank rusts and the tank module falls thru into the tank

Prolly a good time to give the entire tank an in-depth inspection

Are the roads salted in snowy weather, or just natural failure from DCX not protective-coating anything under the truck?

 

The roads are salted over here- especially the highways, you can easily have about 3-5mm of salt crust after 3 days.
The module is in an ideal position to catch a lot of spray on my truck- don't know whether this is different for other model years or wheelbases.

I think it's astounding how different the engine is running now. It seems to me that there must have been a long standing problem with fuel aeration because the change in engine sound and also engine power is significant (seat of pants dyno only)
What I did notice is that since I did the line my EGTs are lower when just putting around.
I do also need to push the truck much harder to get it to smoke- no way to get it to smoke from 30mph now on wet roads. (will loose traction before it smokes)

I think that the VP44 trucks will still run with a lot of air in the fuel- and this may be one of the differences in fuel mileage we do see across this board.
I think I'll try something similar to my fuel bleed test with the 12V of a friend of mine. I'm curious whether there are bubbles or not.. (especially at high revs with the 12V)

About the tank rusting- my 98 already has the plastic tank so no rust to be feared there. But still there are the holding straps to rust through

AlpineRAM

 

AlpineRam - good post! I will be doing that chore next spring. I'm curious, was the inside of your fuel tank real grungy? Did you see any algae or such? What chemical did you use for cleaning?

 

The inside of my tank was almost spotless, a tiny amount of water ice (about 1-2 teaspoons) and about 1/2 teaspoon of rust and other solid junk (I think I got this into the tank when removing the module)
I'm running lots of bio and the fuel over here is much cleaner than in the US.

If we have to clean fuel tanks we usually take the high pressure washer and get the crud out, then dry them and clean with brake cleaner on a rag. (This is for the PE/PP tanks)

HTH

AlpineRAM

 

You have got to be kidding! I would PAY someone to see it done When I changed the fuel system on my truck I was never able to undo that doggone connector, and ended up lowering the tank as much as it would go without braking the wires and working around it like a fool. I tried to look at the connector this way and that, and figured that one has to somehow disengage some red clip on there, but neither prying, pressing, pushing or peeling the darned clip seemed to help. I was tempted to clip the wires, pull the tank out and find out how in the world they attached the connector but then had a beer and remembered that I was not under there to do damage, just to fix the fuel system and the module did so far work fine... so I had another beer and left it alone.
-P

 

LOL, somehow I think Alpine had already gotten the stupid red plastic lock off on a prior occasion......... Don't feel bad man, I tried and tried, thought about doing the same thing, finally said the heck with it like you did.

Someday I will remove the lock and leave it off for good!

 

With this flatbed on my truck, I'm able to look right at that rascal standing beside the truck. I know what you mean when you say you would pay to see someone unplug it with the stock bed.

 

The first time I had to do mine I did wash the top of the tank with a garden hose for 30 minutes. Then I sprayed it with some penetrating oil. Ten the tab did slide towards the front of the vehicle when using some force. I found that these safety tabs fill with salt and road grime so they can't compress the little slit they have and then they are stuck.
Time and water usually helps a lot, but you need to use contact spray or dielectric grease on the connector after drying it really good.

AlpineRAM

 

I don't catch your drift - what issue were you addressing with the changes that you made?

 

I adressed the problems that the in tank module in some cases has the suction line perforated by a screw on the inside of the tank, then that the quick connect fittings on the tank can start to leak, and that the metal part with the quick connect fitting can rust through. I had all of them happen to me. All of them led to aerated fuel and the VP44 hates that.
I am working on creating a "plug in" fitting that can be used with standard 3/8" fuel hose and reuses the in-tank module for a cheap and quick repair that adresses all these issues and also gives a min. id of 9mm from within the tank to the lift pump.

AlpineRAM