Cummins fuel problems - What ya got?

[J RAD]

Hi guys. Got a bit of an issue with our top lifter (like a container fork lift) at work.


Its been running rough for about 2 weeks now and its getting worse to the point its stalling. Its as if its not getting fuel and not firing on all cylinders.


We've had a real good go at trying to fix the problem, but I'm now coming to the wisdom of AULRO members.


The actions we have taken are, run injector cleaner in the fuel, bleed from the injectors (about 10 times), replaced all the rubber fuel lines, replaced both filters, replaced all brass washers on fuel lines, blew compressed air through all lines to check for fuel bug, pressurised the fuel tank with compressed air hopping to find a hairline crack, taken apart lift pump (still makes vacuum) also kicked and swore..... a lot.


The only thing I can think of now is a problem in the tank it self, maybe a crack in the pick up.


We are more than happy to hear any suggestions at all. what have you got for me???

[Blknight.aus]

put a t piece in the delivery line from between the lift pump and the injector pump. fit a tap or blank to it.

get the engine running and then open the fitting, if its pumping frothy fuel then you have a fuel supply issue

if it starts to die as soon as you open the fitting then you have a delivery problem from the tank to the lift pump or the lift pump itself is faulty.

get a jerry of fresh diesel some fuel line and a facet pump and bypass everything but the injector pump give it a run.

If that doesnt get you running smoothly you have a problem in the injector pump, from there it comes down to which pump are you running?

[J RAD]

Righto. Ill have a crack tomorrow morning. Thanks mate

[whitedisco]

Blocked finger filter on the fuel pickup in the fuel tank?
I have seen that in a bus once.

Cheers
Peter

[J RAD]

Blocked finger filter on the fuel pickup in the fuel tank?
I have seen that in a bus once.

Cheers
Peter



I've blown air back through the lines to the tank. But still runs rough on start.

[Tank]

If it is the type Cummins engine that pumps the fuel through the head to the cam/rocker arm operated injector, then it could be a number of things including blown or worn O rings in head or the rocker needs adjustment, may need to get it pressure tested, Regards Frank.

[whitakerb]

What's the engine model / serial number?

Should be on the timing cover on the right hand side (looking from the front) or on the rocker cover

[Homestar]

Large container fork would run a 6B or 6C - both mechanical engines, but if it's fairly new, it could be running the electronic versions - ISBe or ISC.

[Gerokent]

I've blown air back through the lines to the tank. But still runs rough on start.

Only running rough on start?
Sucking air into system somewhere.

[whitakerb]

Large container fork would run a 6B or 6C - both mechanical engines, but if it's fairly new, it could be running the electronic versions - ISBe or ISC.

That's what I was thinking. Do the 6Bs and Cs have the small fuel strainer in the back of the fuel pump like the QSX15s do? From memory you have to remove the fuel inlet fitting and dig the strainer out from behind it with a scribe.

[Homestar]

That's what I was thinking. Do the 6Bs and Cs have the small fuel strainer in the back of the fuel pump like the QSX15s do? From memory you have to remove the fuel inlet fitting and dig the strainer out from behind it with a scribe.

Not that I can recall, no - they should just have a fuel filter and water separator up on the engine - fleetguard numbers FF5052 and FS1280 IIRC (wow, how many of these have I serviced in my life... :D ) then straight into the pump. The QSX15's have 2 of those strainers - there's one in the spud on the fuel filter too - same part number, everything. You can clean one out and still get hard starting - I think it's their just to catch you out ;). IIRC there is a 14mm hex head screw needs removing to fish them out, but I haven't done one in some time.