Cummins 4BT fuel problems

[ktm250rider]

Nope, not it or it's just not right enough. Started right up but rpms fell after about 20 min.

 

[funwithfuel]

Did your primary fuel filter remain full?

 

[RZucker]

fuel tank vent, could i just leave the cap off to check? There are two water filters, one between the tank and pump. Now that i think about it, there is a fuel filter and water filter at the top of the engine, not sure where those feed lines are.
i replaced the lines from the tank, to the first filter and then to the lift pump. They were cracked, thought that was my problem but nope.

That filter between the tank and pump could be your problem. it's a pos that will suck air even though it looks good. I trust them as far as I can throw them. If you have crap in your tank, bypass that filter with a clear inline type and run it awhile to see what you get.

 

[ktm250rider]

Filter up top of engine remain full. I'm back to that union. I just found it leaking. Im going to replace that next.

 

[ktm250rider]

shoot, anyone got a part number for that? My manual is on my work computer and I shut it down for the week so i cant log onto it remotely. arrghhh, i almost took that stuff home too.

 

[Coy Lancaster]

shoot, anyone got a part number for that? My manual is on my work computer and I shut it down for the week so i cant log onto it remotely. arrghhh, i almost took that stuff home too.

J303310 is the new part number it's a one piece line now.

 

[ktm250rider]

Awesome, thanks. I found a manual but could only find half the line. 1 piece is great.

 

[ktm250rider]

Is that the correct number? Cant find it online anywhere

 

[Coy Lancaster]

Is that the correct number? Cant find it online anywhere

That's the correct number according to the Case online parts website.

 

[thepumpguysc]

each one of those pieces have a tag on them w/ the P#.. {prob. painted over}

 

[ktm250rider]

Problems persist. I've run it about 10 hours over the past 2 months with no issue. Put fuel in tonight and died. Bled it 3 times to start and died each time. Pulled filter and it was low on fuel. I didnt pull the water filter but there was nothing coming out when I opened the drain.

 

[Delmer]

That filter between the tank and pump could be your problem. it's a pos that will suck air even though it looks good. I trust them as far as I can throw them. If you have crap in your tank, bypass that filter with a clear inline type and run it awhile to see what you get.

Did you replace this filter? or update us on what was done.

 

[Randy88]

Might be way off base, but I've seen this in other machines, where one of the banjo fittings has a screw in screen inside it that needs to be cleaned from time to time. If you haven't done it yet, I'd take all the fittings out and replace the copper washers in them, then check for the screw in screen.

If it has one, its usually in a rubber line that attached to a banjo fitting, saw two rubber lines in your photo, but over the years those little screen's have given me some grief, doing the same thing your experiencing now with being starved for fuel, then run fine for a while, then act up again.

I've not run into one in a cummins before, but who knows who's done what to it before you got it, just tossing out ideas and things to look for others have not yet mentioned.

 

[Delmer]

The scenario given sounds a lot like bacteria growing in the tank. Look for some slime in the filters, strainers and water separators. You mention a fuel filter and I think I might have seen an in line filter in the photos. If so did you get it from an auto parts store?

2" of crud in the bottom of a fuel tank is a **** TON OF CRUD in any tank. You have something plugged up with garbage and the system is sucking air. That's my guess. I know you say you cleaned the tank, but I still say you still have something plugged up.

The screen inside a banjo bolt is usually on Japanese Bosch/Nippon/Zexel, usually on the inlet to the piston type transfer pump. Anywhere you open the system and operate the transfer pump should squirt, if it dribbles, keep looking.

 

[Randy88]

I'm wondering if its not time to take the tank back off again and wash it out, then take the lines all off and blow through them all individually.

Back in the day, my father in law ran one entire night chisel plowing with his 4 wheel drive before he realized the fuel cap wasn't on, those tanks were taken off and steam cleaned a dozen times before they finally got it cleaned out good enough to keep the crap out of the lines and the filters clean. Even so years later he'd get corn stalk debris in the filters from time to time.

 

[thepumpguysc]

If u had that much debris in the tank.. & the problem pops up every time u add fuel.. I'd say u STILL have garbage in the tank.. & it stirs up when u add fuel..
There is also a filter inside the inj. pump.. I'll bet money that thing is plugged up.. or did u clean THAT out too??

 

[Delmer]

Come on Pumpguy, not everybody cleans the filters out with a screwdriver to reuse them, or forgets about them for ten years till they fall apart inside, or maybe it does seem like EVERYBODY. If the filters haven't fallen apart inside, then there shouldn't be a plug in your injection pump. Don't let thepumpguy worry you too much. Pumpguy, thanks for the injector nozzle numbers, you saved me a bunch of money. I'll let you know when I get the engine back together, might still have to dig in mechanically, we'll see.

Start at the tank, if it's not plugged in the tank, then before the transfer pump is next most likely.

Don't believe us? there's a couple things to try, run a temporary plastic boat tank and see how it operates, OR put a tee into the fuel line at the outlet to the last filter or close to the injection pump, run a line to the cab and use a vacuum/pressure gauge to see what the fuel pressure is normally and when it dies, or under full load if you can't catch it dying.

Another way to deal with a dirty tank is to use a large hose on the outlet, going to a filter base with a common motor oil filter (ph8a or ph2) that you can pick up anywhere for a couple bucks, then reduce down to the fuel suction hose size. If you ever replace that motor oil filter it will be cheap and you'll know it was worth it. You might be able to put a screen inside the tank, some people HATE those, as much as the banjo bolt screens.

 

[HollerDweller]

Do you have a mechanical lift pump? I have not red the entire thread, but it may be causing problems. Sometimes the diaphragm doesnt go before the rocker arms wears prematurely. Some times they will form cracks and bend just enough to cause an issue. I am a big fan of electric fuel pumps. Can help alot with air intrusion and cold starting.
You should also have banjo fittings and olives. If you have not cleaned/removed the screens and replaced the olives you might try that. It is probably due for olives anyway. Those always get overlooked. If you have rubber return lines replace those as well. Air intrusion happens long before an external fuel leak.

 

[HollerDweller]

Also you can pour some kerosene with a couple bottles of atf in your tank to get it clean. Just let is sit in there for a while and drain it. You can also fill your fuel filters up with ATF and run it for a minute and shut it off and let it sit for a few days. Will clean everything out from your tank lines to injectors.

 

[ktm250rider]

Yup I'm going with crud in the tank. I recently replaced the filter between tank and lift pump, so I ignored it. Well wouldn't you know that thing was just packed with gunk. I was shocked it even ran.
New filter tonight and ran great. Once I burn through the tank, it's getting cleaned out again.