FLU fuel issues

[The FLU farm]

I did add some to in and bent the track bars a bit to get the rear axle tracking right.

Would the adjustments not allow centering the axle, or did you bend the bars to get it done quicker?

 

[911joeblow]

Would the adjustments not allow centering the axle, or did you bend the bars to get it done quicker?

My bars, like most of the Texarkana trucks are bent because they got lifted up by a telehandler on them. I wonder of some of the handling issues people have might be because the rear axle is cocked and articulated forward shortening the track?

 

[General Hood]

Today I learned several things while spending a few hours trying to clean out the tank. One is that the (formerly) parts SEE really is a SHEE.
Since this particular tank won't come out easily, the cleaning consisted of draining, scraping, wiping, and scrubbing. This was repeated three times, while wishing that the pressure washer somehow could be made to spray diesel instead of water.
Partway through, the line from the valve to the pickup was blown out with compressed air since yesterday's adventures indicated that the pickup was blocked, again.

Maybe half a coffee cup's worth of crud came out this time, making the total about three or four full cups. Surely there's more towards the rear of the tank, which I couldn't reach.
What likely happened is that the solidified "JP8 chemical reaction remains" got loosened up once subjected to anti-gel and other additives, turning into crud with particles ranging in size from fine sand to coffee grounds and slightly larger.

Took a test drive and got about twice as far as yesterday before fuel starvation symptoms set in again. Not enough fuel flow to support 2,300 rpm in high gears - which is something I would normally never aim for, but I want this fuel problem fixed.

One final (desperate?) thought was to clean the strainer's filter. While the cup has been cleaned out numerous times, I don't think that I ever cleaned the filter itself. This bright idea was triggered after seeing how much fine stuff was floating around in one of the pails the fuel had been drained into. I'm used to just dumping out the big stuff, not paying attention to the filter itself.
Took some parts cleaner and sprayed away, reinstalled (there was very little crud in the strainer this time, by the way) and took another test drive. Finally! No guarantees, but that might have been the final thing. Well, until more crud plugs up the pickup and/or strainer, anyway.

So what I've learned is that if there's a vacuum in the strainer, there are no air leaks farther upstream.
Having chased air leaks for a long time, it seems that an empty (no fuel) strainer is a sure sign of air leaks. Before or after the strainer.
New copper washers are so worth it. In my trials with an electric pump, there were never any visible leaks, yet things improved with new washers.
A bad pickup tube (pinhole) could make the vehicle run only with a certain amount of fuel in the tank. Thankfully, that's not something I've experienced, yet.
Not enough fuel, but the strainer is full, may indicate a bad vent on the tank or a blocked pickup tube.

Now that the SHEE runs better than ever, perhaps an explanation of that new name is in order.
SHEE needs constant attention, or gets moody. Even after installing new shoes, SHEE wasn't happy for very long. Then there's the leak in the rear which isn't constant, but periodic.
I could go on, but you get the idea.View attachment 681147View attachment 681148View attachment 681149

If you recall, I dropped the fuel tank on FLU #2 last summer and scrubbed it clean. Less than a year later the entire inside of the tank is once again covered in this rust looking growth (top to bottom) and once again causing problems with clogging the strainer screen. You can see by this photo, it looks like the tank had never been cleaned. It's interesting that the other FLU I picked up from the same GP location (same year model) has a problem free fuel tank.

 

[The FLU farm]

My bars, like most of the Texarkana trucks are bent because they got lifted up by a telehandler on them. I wonder of some of the handling issues people have might be because the rear axle is cocked and articulated forward shortening the track?

Ah, I guess I misunderstood you then. You didn't bend the bars, you straightened them a bit, right?
I didn't dare drive the SHEE with bent bars, not knowing what the effectively shorter wheelbase would do the driveshaft, transfer case, and U-joints.
After straightening them, I put them in the same position in the serrations as the had been, but never did check if that's the correct position as far as alignment goes.

 

[The FLU farm]

If you recall, I dropped the fuel tank on FLU #2 last summer and scrubbed it clean. Less than a year later the entire inside of the tank is once again covered in this rust looking growth (top to bottom) and once again causing problems with clogging the strainer screen. You can see by this photo, it looks like the tank had never been cleaned. It's interesting that the other FLU I picked up from the same GP location (same year model) has a problem free fuel tank.

Yikes! I'd give that tank's interior a bath in N-Terpinal (or one of the now common brands, such as Evapo-Rust - which is probably an N-Terpinal product anyway).
Then you'll have to figure out where all that moisture comes from. I'd think it has to be condensation.

 

[General Hood]

Yikes! I'd give that tank's interior a bath in N-Terpinal (or one of the now common brands, such as Evapo-Rust - which is probably an N-Terpinal product anyway).
Then you'll have to figure out where all that moisture comes from. I'd think it has to be condensation.

I thought condensation as well, but I keep the tank topped off, and the rusty stuff covers the entire inside of the tank.

 

[The FLU farm]

I thought condensation as well, but I keep the tank topped off, and the rusty stuff covers the entire inside of the tank.

I was afraid you'd say that. Bad fuel doesn't make sense to me, either, as the water should go to the bottom.
One thing to try could be a hefty dose of an additive that absorbs water. Although, the rust that's already there is still a problem.

And speaking of crud in the tank, the sand (?) I found on top of the skidplate today looks suspiciously similar to what I've been flushing out of my tank. Just a different color.

 

[General Hood]

I drained my tank again yesterday, the fuel looks to be okay, but the tank was a different story. I scraped some, shop vac'd some, used a little southern engineering to get a wire wheel up in the tank to hit some stubborn spots (BTW, face protection advised, I sure didn't want that rust looking crud up in my eyes and nose) The inside of this fuel tank is heavily pitted, and I'm thinking those pits might be a breeding ground for whatever micro-organism , nuclear waste product caused the initial assault on the tank.
I haven't refueled the tank, contemplating on researching additional cleaners or protectant products that may be beneficial to the health of this tank, or buy a new tank and be done with it. I'm missing a barrel under my boat dock and that FLU fuel tank is just about the right size. BTW, thanks FLU Farm for the emailed tips

 

[The FLU farm]

Hey, until my back lets me work effectively again, I might as well read up on the subject - and pester you by email.

 

[The FLU farm]

It could very well be a pure coincidence, but either the crap in the tank has finally gotten flushed out/caught in the strainer, or the BioBor did its job.
Ran the backhoe for an hour plus today, and when checking the strainer there was very little crud in it. Just like the time before.
If pouring some anti fungus stuff into the tank solved my fuel issues, I'm a happy camper. One who wishes he'd done it a year ago, but still.

 

[LZahariev]

I noticed today that my tank is filled with a brown gunk that is sticky to the touch. I drained the tank and the fuel came out clean. The gunk is settled on the bottom of the tank and doesn't seem to be mixing with the fuel. I wiped as much as I could by sticking my hand in the tank but seems like there is a lot more. The tank looks clean on the inside without any rust. Anyone have any idea what this brown gunk could be? An old fuel stabilizer? The fuel strainer was also covered in that stuff.

 

[The FLU farm]

These days my guess is that it's fungus/bacteria crap, literally. Try a biocide of your liking and see what happens. Worst case, you won't get any fungus in there.
I tried to fight that war for a long time without using chemicals (other than normal additives) and lost.

 

[LZahariev]

I will try cleaning it with chemicals. Thanks.

 

[The FLU farm]

Well, a biocide won't clean it per se, but kill the fungus that creates the poop which is what we see.
In my case it was partially like sand, partially like a spray-on bed liner. It took quite a few cleanings of the strainer, after having cleaned the tank out best I could with it in place.

 

[LZahariev]

I plan to clean it in place. Thanks for the info.

 

[LZahariev]

More fuel system chronicles. I have owned my SEE for about 6 months. This is the first time having fuel system issues. I noticed the brown sticky slime on the bottom of the fuel tank shortly after I brought it home. The fuel tank was cleaned in place. I was never able to get it completely clean but felt it was enough at the time. Two days ago, as I was moving a heavy gun safe with the backhoe, the truck was parked with a steep backward tilt. With less than a quarter tank, the truck got a healthy helping of air in the fuel lines. After topping off the tank and bleeding the fuel lines by a constant pattern of hand prime pump, bleed the fuel filters, and crank the engine; the Truck was running again allowing me to finish the task at hand. The following day the SEE started a bit shaky followed by rough idle. Soon it was back to the prime pump and bleeding again. I did notice the hand pump was not releasing air/fuel through the fuel filter bleed screw with the same intensity. I finally removed the fuel filters to find them completely clogged with the brown sticky slime. They were so clogged that the hand prime could no longer push fuel past the filter element. I have ordered the complete fuel filter assembly and the screen filter near the tank for replacement. I just hope this brown fungus has not contaminated anything in the Bosch fuel injection pump. Has anyone fighting this mystery sludge ever found traces on the high pressure side of the fuel system and had to remove the Bosch pump for cleaning?

Thanks

Lu

 

[peakbagger]

Wow sounds like a major PITA. I haven't heard of crap getting to the injection pump through the filters. The stock felt Mercedes fuel filters do have a good reputation of stopping anything from getting to the injection pump. This filter arrangement was used for decades on multiple engines and going back to the Unimog agricultural roots, the fuel system was designed to deal with low quality fuel.

Others with far more experience with Bosch injection pumps have advised that the injection pump is lubricated by the fuel and repeated attempts to start the truck with no fuel is not good for the injection pump. As you are doing, the right way to do it is prime the filters and then attempt a start. If it doesn't start quickly reprime. Some folks apparently like to skip the prime step and just crank the engine repeatedly hoping that the air will eventually work its way out of the system. I expect all of us have figured out that if the fuel system is up to snuff and the filters are primed, the engine will start quickly.

 

[Migginsbros]

Some pics from inside our tank.
After reading about the brown sticky slime find the way to the 2 big fuelfilters we ordert them, too.
Perhaps we have the time on saturday to change them.

 

[The FLU farm]

I have ordered the complete fuel filter assembly and the screen filter near the tank for replacement. I just hope this brown fungus has not contaminated anything in the Bosch fuel injection pump. Has anyone fighting this mystery sludge ever found traces on the high pressure side of the fuel system and had to remove the Bosch pump for cleaning?

I'd think the filters did their job and kept the crap out of the injection pump. The fungus/bacteria is probably all throughout the system, but when even modern and much more finicky pumps can tolerate that, I don't think it's an issue on a SEE.

The strainer's mesh can easily be cleaned with almost anything, so there shouldn't be a need to replace that one.

Do yourself a favor and order up (at least) new washers for the banjo fittings from Bel-Metric before replacing the filter assembly. I've learned that it's worth replacing them no matter how good they may look. Oh, and you can get rid of the diagnostic gizmo on top while you're at it.

I have yet to find any fungus/bacteria crap in the filters, it has so far only made it to the strainer, but it looks like I'm getting down to the finer particles in the tank now so a check of the first one may be in order. And letting another gallon or so out of the tank and see what comes out this time.

 

[LZahariev]

I was trying to figure out what that gizmo on top of the fuel filter assembly was intended to do. I will go ahead and remove it. I plan to replace the fuel filters before having some Turkey.

Thank you to everyone that replayed!