Thinking of installing the FASS tank Sump as I'm getting some minor fuel cavitation below half tanks of fuel. I hear fuel pressure drops are not as dramatic when hauling heavy up hills and the lift pumps running quieter. I already have all the fuel system mods except for the tank sump but I have one concern....

 

I read some discussion that it is illegal to draw fuel from the bottom of the tank in some states. Anyone know about this?

 

Also wondering if anyone heard of leaks from any tank sump installs.

 

Merry Christmas to everyone

 

Edited December 24, 20168 yr by JAG1

All I can say is do your research for your state laws. Check with Oregon DOT ask them. As for he sump I'm still staying away from them. All the videos show dragging an empty tank. Try driving over a rock or a log with the tank installed I bet the mighty Cummins will shear it right off.

Edited December 25, 20168 yr by Mopar1973Man

I plan on putting a bent upwards skid plate under it. I have a simple way of doing that.

"Also wondering if anyone heard of leaks from any tank sump installs. " 

 

Mine had or has a leak. Don't know which yet because waiting after Christmas to get diesel all over me again.  It appears that last mechanic torqued the screws and stripped some threads on the horseshoe thing that goes inside tank, that the sump screws onto.  Also I had two nylon washers cracked/broke. FASS thought maybe that's why a leak in first place?  I have installed it but not tested for leaks yet.  Also look up torque spec's on sump,  if I remember right, 30 inch pounds.  I don't have a "good" inch torque wrench.  FASS said finger tight then 1/4 turn with allen wrench is same thing. 

 

A lot of trucks at where I retired from have a "cross over" fuel line at bottom of tank to equalize fuel.  Over 25 year period 3 or 4 got nailed.  And they had metal protection, usually just a piece of angle metal. 

 

My sump was installed at the rear of tank,  just at end of my fingers when reaching in tank.  Would be lots easier if sump was closer to fuel module opening.   Mine is also 2 wheel drive.  I don't like seeing hose that close to ground.  Hopefully, I won't have to use my sump as I also have a draw straw pick up tube and modified fuel module.  

 

Idea...maybe not worth a darn but ...  If you have good venting, would attaching a longer hose with maybe a coil or two laying on tank bottom with the end aimed away from anything help with cavitation?

 

 

Edited December 25, 20168 yr by 015point9

I did a little looking around and did not see anything definite about legality. Sounds like some more searching is in order.

I guess until mine starts giving me trouble I will stick with what I have too. In the 6 or 7 years I have had the AD I have never heard it run except when the engine was off. I know my ears aren't what they used to be but I still cant hear it unless I get under the truck. 

015pointnine, thank you for that information. Certainly some things to think about.

After you had the sump installed, did you notice any increase in fuel pressure or any less drop in pressures at WOT?

 

Driply, I found some information from  the company that makes transfer tanks and they said several regulations from several gov't agencies come into play making some things apply only to big rigs, others to all vehicles. It ends up that one thing is certain that all vehicles must draw from the top of the tank, but, it's worded in such a way saying that no vehicle can be gravity fed. So I don't know if this applies since we still need a lift pump to push fuel up to the VP.

 

Dang.... I wish I could remember the name of the company, I hear it all the time since it is so popular. The info is on their website since they've done research on the regulations. Is it Transfer Tank Co.? dang memory Beer always helps a lot

Edited December 25, 20168 yr by JAG1

"015pointnine, thank you for that information. Certainly some things to think about.

After you had the sump installed, did you notice any increase in fuel pressure or any less drop in pressures at WOT?"

 

Can't answer your question.  I limped back home from Yuma to Northwest with new airdog pumps using the new sump.  Because old FASS  pump fuel system fell apart (11 years old and 90,000 miles)  Only test that was done was at different garage (because I didn't trust other guys work after seeing install) and idle and that was 21 pounds.  Got back home and tore everything out in late Sept to install fuel pressure gauge and to run hose better and then wife fell apart.  It's been one Dr appointment after another or raining most other days. 

 

When I put mine back together, I'm going to try to use fuel module first.  If it doesn't work, going to try draw straw.   Reason...with a sump the only thing you got is an "O" ring".  And you're stuck with hole in bottom of tank for a long time, if you don't like it.   With the module or draw straw, if anything goes wrong, at least those holes are at top of tank, not on bottom.

 

(Be aware) Directions on FASS sump says to use "mega black" dope on screw threads.  I had none.  Maybe that's why I had leak, and screws were torqued way over spec, hense a couple cracked the nylon washers, which might of been reason for my leak?

 

 

Edited December 28, 20168 yr by 015point9

@JAG1 we're you thinking of Transfer-Flow?

Yes Transfer- Flow, Thanks BBHD.

 

015point9, again thank you for the great detailed information. You wrote a long post to make sure I understood, but, most important of all....... you say your wife is getting better. Wow! That is great.

 

I repaired an entry door for a friend of a friend. He came down stairs to thank me but, two weeks later he was gone from the same thing.. Prayers from Oregon for your sweetie point9. Merry Christmas to her and you.

 

BTW, after reading your above post I don't think I will be doing the tank sump. I like the crossover tubes idea. I'm assuming they give the fuel time to gain momentum of flow before going straight uphill like a verticle draw straw. Is that right?

Remember im an old school drawstraw user for nearly 11 years now and ticking. Still no serious issues. Still capable off reaching the empty mark.

Yes Mike, when I get out your way again I'll have less than a half tank and let you drive my truck, if you can stand the automatic, you'll hear the cavitation and see the sudden F/P drop on the gauge.

Most likely your straw was trimmed wrong. I've seen plenty of bad installed draw straws. I've even got a new straw in my shop right now. I'll even sell it...

Okay, how much for it? Mine was the first one Eric ever did. He was trying to do some of the design when he put mine in, but got cut about an inch short so I added a piece of rubber hose to get nearer the bottom of the tank.

Eric has helped a lot and always will recommend him. Got my new VP from him.

Edited December 25, 20168 yr by JAG1

Eric sells the same thing for cheap. I place a quarter coin on the bottom and cut the tube to rest right on top of that quarter. FASS suggest 2 quarter coins stocked. I still do only one. Always do it with a empty tank. The bottom will deflect with fuel weight. So empty it will be right to the bottom but filled it will be farther away.

 

I'm going to bet your hose got rotten and floppy.

I think you are right since it's gotten worse in recent long runs.

Rubber hose won't last in diesel fuel. This why the tube is either metal or plastic. I like metal over the plastic.

1 hour ago, Mopar1973Man said:

I'm going to bet your hose got rotten and floppy.

 

 @CSM

My .02 on sumps. I had a draw straw in the fuel module with an AD II. I had ridiculous pressure drops with it feeding a p7100, like +30psi drops at wot. I installed a beans sump and saw only a 20psi drop. This was pulling the truck in the shop one morning and installing the sump and going right back out. I have been sold on their use since. The legality of it...I have not once been stopped or asked about it. Same goes for the hood stack. There are a ton of modifications we make to these trucks that are technically illegal. Oh well lol