Fuel issue, need some help

[jlb8748]

It's driving me crazy I tell ya. Just when I think I have a handle on things something else just decides to happen. I'm the type that hates to leave something unfinished. I'm just at a stand still now with the project until I get this resolved. Not going to go through putting the floor and framing the interior on a bus that is not running.

[Rusty]

Originally Posted by jlb8748

I'm just at a stand still now with the project until I get this resolved. Not going to go through putting the floor and framing the interior on a bus that is not running.

Step 1) Get bus running GREAT. You are doing it correctly.

Skimmed your post, it'd sure help us diagnose your issue if you filled-out your profile so we know what engine it is, year, milage, etc.

We love pictures 'cuz we will see stuff you don't- more eyeballs.

[mmoore6856]

Post pictures of the filters and lines

[golfersmurf57]

Originally Posted by jlb8748

So just to update I went under the bus again today to inspect the fuel line more closely and I found a point between the main and secondary filter where the two lines connect. This part had a lot of gunk and debris caked on which and smelled like diesel so I'm hoping I've found where the air is getting in the line. So I tightened it as much as I could and went back to fill the secondary filter and went to disconnect the fuel line so I could prime it and for no freaking reason other than this bus hates me the nut stripped right away. So now I have no way to prime it enough to get it to run long enough to see if that fixed the problem

First of all my condolences on the 8.junk Detroit here's how to find your suction leak: make an adapter for fuel inlet attach a pressure regulatorand apply air pressure adjust pressure slowly upward so not damage tank cap off other tank if you have 2 your suction leak now leaks fuel which can be seen with inspection. Don't use more than 30 psi this is how I find them and I'm a tech

Sent from my LGL64VL using Tapatalk

[Rusty]

Originally Posted by golfersmurf57

First of all my condolences on the 8.junk Detroit here's how to find your suction leak: make an adapter for fuel inlet attach a pressure regulatorand apply air pressure adjust pressure slowly upward so not damage tank cap off other tank if you have 2 your suction leak now leaks fuel which can be seen with inspection. Don't use more than 30 psi this is how I find them and I'm a tech

Sent from my LGL64VL using Tapatalk

30 psi is high- 10psi is fine. Like he said- go easy, plug your vent lines. I made this modification to fuel cap and showed my lines had many tiny cracks- replaced all fuel lines with good stuff (hydraulic pressure hose).

[mmoore6856]

Yea i used 10 to 15 with no problems also. Still would like to see pics of the filters and lines

[jlb8748]

I'll post pics later today when I get back to the bus. I'll take pics of the entire track of the fuel line so you guys can help me identify what each part is. I've read about putting pressure to the system this way. just so I understand when I add air to the tank it will create pressure that will eventually force the fuel into the lines and wherever air has been getting sucked in I should be able to see fuel leaking out of correct? Would this method also work to prime the system once the leak is fixed? The secondary filter also has three screws that go in the top that I'm guessing is for bleeding, would I be able to hook up my hand pump to one of those and manually pump fuel in to prime as well?

Sorry for sounding like a noob but I am to this kind of stuff. I'm more of a carpenter than a mechanic but I'm learning a lot from this site.

[golfersmurf57]

Originally Posted by mmoore6856

Yea i used 10 to 15 with no problems also. Still would like to see pics of the filters and lines

The parts books online will help you there. I dl to my laptop in a folder for easy access if you have the cloth covered lines some times just the hose can be renewed plastic compression lines will require new ferries

Sent from my LGL64VL using Tapatalk

[jlb8748]

Originally Posted by Rusty

30 psi is high- 10psi is fine. Like he said- go easy, plug your vent lines. I made this modification to fuel cap and showed my lines had many tiny cracks- replaced all fuel lines with good stuff (hydraulic pressure hose).


Attachment 16187

What kind or brand of hose did you use? I'd love to just replace all the hoses and not have to worry about this again.

[golfersmurf57]

Is it inverted flare or compression fittings?

Sent from my LGL64VL using Tapatalk

[jlb8748]

Inverted flare from what I've seen

[Rusty]

Originally Posted by jlb8748

What kind or brand of hose did you use? I'd love to just replace all the hoses and not have to worry about this again.

Mine originally had 1/2" JIC push-fit hose ends. Love JIC (military uses them), hate push-on as is held by barbs and eventually gets air leaks.

I bought a 3/8" kit from Discount Hydraulic Hose that uses 2-wire 3000psi hydraulic hose. It is way overkill, nobody normal does this, but the kit with 2 field-installable ends (just a couple wrenches, no crimp$$ tool) 25 feet and 2 fittings was $70.



You cut it with a angle grinder/air cut-off tool. I slid my old hose out of that corrugated plastic cover and fed the new in it's place. Didn't unbolt all those existing hose supports, but did have to replace zip ties. Put bolt in hose before feeding to keep crap out.


my build

I also put a real lift pump by the fuel tank as liquids liked to be pushed, not sucked. Injection pump will try to suck fuel if starved and that kills them $$$$$$.

Now when I leave the bus for a few weeks and go to start, quick bump and vroooom. No cold cranking from air leak killing batteries and long cranking to prime.

[Tango]

Hey Rusty...good info, thanks. Also, what pump did you go with?

[Rusty]

Originally Posted by Tango

Hey Rusty...good info, thanks. Also, what pump did you go with?

Cummins used that crappy little carter lift pump mounted on the motor- where it's hot and vibrates, then dies. When they die, you don't know and the VP44 will try to suck fuel from the tank, until it dies.

I went with the Air Dog Raptor- it has an adjustable pressure regulator built-in. The pickup guys like that one or the FASS. Reused the old separator and ran the power wire back-up to the plug for the old carter. Very happy with it.



At the engine, I kept the secondary filter and fed right into it as it has the WIF alert (water in fuel) and useless pre-heater. Some guys who want mooor power bypass the canister and feed the pump directly, but it is uber tight fit in FE bus.



I used proper JIC fititngs- online or speedshop (jegs). JIC fittings are measured in 1/8 ths, so AN -6 is 3/8 hose. The"F" is fuel filter on motor, the arrow points to fitting with plug for fuel pressure gauge at the engine (on order).




Cummins 5.9L likes 15-18 PSI @ WOT.

[golfersmurf57]

Ok the hose is called stratified usually the ends are reusable the outer barrel is left handed thread and screws onto the hose the actual fitting then is screwed into the outer barrel by wiggling it inwards toll the threads catch the fitting spreads the inner liner thus gripping the hose some have wrench flats on the inner piece this that don't you will need an extra fitting to tighten to the connection end so you can turn the inner fitting it will be right hand thread if it is not reusable there will be crimper marks on the outer barrel take a line with you for proper sizing

Sent from my LGL64VL using Tapatalk

[golfersmurf57]

Oops meant stratoflex

Sent from my LGL64VL using Tapatalk

[golfersmurf57]

If memory serves me the 8.2 only ran about 7 lbs fuel pressure like the older 71 and 53 series do just enuff to fill those mechanical injectors.

Sent from my LGL64VL using Tapatalk

[Brad_SwiftFur]

Originally Posted by jlb8748

I'll post pics later today when I get back to the bus. I'll take pics of the entire track of the fuel line so you guys can help me identify what each part is. I've read about putting pressure to the system this way. just so I understand when I add air to the tank it will create pressure that will eventually force the fuel into the lines and wherever air has been getting sucked in I should be able to see fuel leaking out of correct? Would this method also work to prime the system once the leak is fixed?

This is *EXACTLY* how we did it on the farm with our older mechanical DT466, 3208 Cat, 8V71 Detroit, 350 "Big Cam" Cummins, 6.9/7.3 Ford/IH engines, dozens of farm tractors (of course, many had gravity-fed systems) and whatever else I am forgetting. Doesn't need much pressure, 10 PSI or less should do it.

[mmoore6856]

Mack used the same plastic line for thier ail lines as for fuel. Use the brass sleeve compression fittings and 5/8 for suction and 3/8for the return line. The Schrader valve he put in his cap can and has been used to prime these motors (by me also)

[golfersmurf57]

Not familiar with the 4 stroke Detroit priming method. Old 2 stroke we used the wing nut on the valve cover and removed rear crossover pipe and filled the rack with a hose then reinstalled the the pipe and cranked it up and held throttle wide open till it caught and ran

Sent from my LGL64VL using Tapatalk