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6.7 Cummins Crank No Start

dieseldog5.9

Senior Member
Joined
Aug 11, 2014
Messages
614
Location
New Hampshire
6.7 Cummins in a LouGong G856 Loader. Operator changed the fuel filters he thought gelled up. After changing the filters it ran a few minutes died and hasn"t run since.

Spent quite a while priming the supply side of the fuel system, and am confident that is good, however the high pressure side i am not confident in, are there any special instructions for priming the high pressure side, big warning label on high pressure manifold about not opening injection lines, however old time machines need the lines bled.

Tried hooking older Nextiq scanner to the loader and it picked up no ECM available, not sure if this is due to being a LouGong, the fact it is a truck scanner, older programming, or the ecm is dead and that is what killed it in the first place.
 

Welder Dave

Senior Member
Joined
Oct 11, 2014
Messages
12,546
Location
Canada
Were the filters gelled up when they were taken off? If so there could be gelled fuel in the rest of the fuel system. Do you have a way to warm the machine up?
 

funwithfuel

Senior Member
Joined
Mar 7, 2017
Messages
5,600
Location
Will county Illinois
Occupation
Mechanic
Back to basics. Why were the filters replaced? Had the machine stalled already, was it low on power? Have you got a schematic for the machine? Have you checked your fuses? Does it have a Cummins ECM or is it the manufacturers. Do you have ECM fuses near the batteries or by the starter? What level of emissions do you have? III, IV Interim or IV final. I dont think they came over till we were into tier IVi .
 

AllDodge

Senior Member
Joined
Apr 2, 2011
Messages
2,312
Location
Kentucky
A 6.7 is easy to bleed the air out, or at least all of them I've worked on.

Turn key ON, just bump starter (do not crank) and listen for the fuel pump to stop.

Turn key OFF, Turn key ON, bump starter and listen for pump to stop.

Repeat this 2 more times, Turn key OFF, it should be good to do one more time and start
 

partsandservice

Senior Member
Joined
Feb 14, 2011
Messages
846
Location
Georgia
It would seem there would at least be warning lights light in the cab yellow and red if not some kind Murphy display or the like. If there are warning lights , when key on they should both light up then go off, if they don't come on at all the ecu is not powering or you have a possible no data connection to a dash module if equipped.
 

dieseldog5.9

Senior Member
Joined
Aug 11, 2014
Messages
614
Location
New Hampshire
Ok so got this figured out, so I was building an engine in the shop by the woodstove when owner came in said loader quite, he panicked and called dealer, scheduled a visit from the big fancy service truck, because the bigger and newer the service truck the faster better the repair is, oh fancy decals help too. They will be there next week. Ok he has it handled I will stay in my lane. This is Wedmesday.

Friday another major manufacturer was onsite for a leased dozer, asked to have a look. He spent the day, after replacing the fuel lines from the tank decided it was the high pressure pump.

Tuesday Dealer came after paying 120 mile road time each way, arrived 11am, left at 4 mostly on phone in truck. He had to call dealer for result, they Said load it on trailer take it to our shop. Owner says it's dead can't load it, not our problem.

I was called for a crane out of fuel on same site, asked if he wanted me to looke at loader. Spent some time priming system found fuel line that was replaced kinked at the tank, got fuel system primed each section to high pressure pump separately, removing filters and lines up to pump. Ran scanner got no ecm picked up. -5 degrees and 5pm so dark. Checked fuses and fuse links at battery.

Retreated to my office posted on HEF, found a trouble tree for crank no start, sat down worked through tree made notes to check, returned to machine found Ecm power slightly unplugged. Fired it up. Loader downtime from me 1 day. Downtime from dealers over a week, who knows how long they would drag it out but hp pump and low bed ride would cost $5000, jobsite working 7days a week 12 hr days.

I think owner was gelled, when changing filters didn't prime machine correctly, other issues I believed caused by faulty workmanship. I showed up in a 10 year old pickup with no letters on the door.
 

partsandservice

Senior Member
Joined
Feb 14, 2011
Messages
846
Location
Georgia
I find that is often more than one issue. Also it seems like that when techs have all the latest and greatest software it is relied on too heavily. It is still just an engine regardless of the teir level. Good for you, you will go far.
 

funwithfuel

Senior Member
Joined
Mar 7, 2017
Messages
5,600
Location
Will county Illinois
Occupation
Mechanic
I find that is often more than one issue. Also it seems like that when techs have all the latest and greatest software it is relied on too heavily. It is still just an engine regardless of the teir level. Good for you, you will go far.
Emissions are to be considered when dealing with fuel systems. Some larger engines have fuel dosing nozzles which parasite off the main fuel system. So yeah tier level and displacement matter.
 

partsandservice

Senior Member
Joined
Feb 14, 2011
Messages
846
Location
Georgia
I agree that Emissions matter, the point I was trying to make is that under all that stuff is the same old engine that still needs the three basics to run. Regardless if how those basics are controlled or administered. Like you said K.I.S.S.
 

dieseldog5.9

Senior Member
Joined
Aug 11, 2014
Messages
614
Location
New Hampshire
Well, I am not a pup, the sorel boots I wore all day today are older than the first guy that showed up on the jobsite, actually he has probably never heard of them before.

I think in these days with all the computerized this and that guys forget about good old fashioned police work, rely instantly on scan tool, I went to diagnostic tree and read the f***ing thing, which is the step so frequently missed today.

Oh and luck helps.
 

kith

Well-Known Member
Joined
Oct 5, 2009
Messages
96
Location
iowa
Ok so got this figured out, so I was building an engine in the shop by the woodstove when owner came in said loader quite, he panicked and called dealer, scheduled a visit from the big fancy service truck, because the bigger and newer the service truck the faster better the repair is, oh fancy decals help too. They will be there next week. Ok he has it handled I will stay in my lane. This is Wedmesday.

Friday another major manufacturer was onsite for a leased dozer, asked to have a look. He spent the day, after replacing the fuel lines from the tank decided it was the high pressure pump.

Tuesday Dealer came after paying 120 mile road time each way, arrived 11am, left at 4 mostly on phone in truck. He had to call dealer for result, they Said load it on trailer take it to our shop. Owner says it's dead can't load it, not our problem.

I was called for a crane out of fuel on same site, asked if he wanted me to looke at loader. Spent some time priming system found fuel line that was replaced kinked at the tank, got fuel system primed each section to high pressure pump separately, removing filters and lines up to pump. Ran scanner got no ecm picked up. -5 degrees and 5pm so dark. Checked fuses and fuse links at battery.

Retreated to my office posted on HEF, found a trouble tree for crank no start, sat down worked through tree made notes to check, returned to machine found Ecm power slightly unplugged. Fired it up. Loader downtime from me 1 day. Downtime from dealers over a week, who knows how long they would drag it out but hp pump and low bed ride would cost $5000, jobsite working 7days a week 12 hr days.

I think owner was gelled, when changing filters didn't prime machine correctly, other issues I believed caused by faulty workmanship. I showed up in a 10 year old pickup with no letters on the door.
This works both ways. I spent most of my working hours in one of the truck with the decals. Customer called to get the starter replaced because it was under warranty. I could smell the fried starter from ten feet away. Local guy serviced the engine with all new filters and fluids. It wouldn't start so he decided to jump it after running batteries low. It had a cold start option so it had two 12volt batteries he didn't check system voltage he just hooked up a 24 volt loader to it. There was arc marks on the frame that should have tipped him off! Anyway after installing starter I checked the fuel filter and found he had not removed old gasket so it was sucking air not fuel,still wouldn't start so I hooked up computer and he had also fried the engine and transmission controller. After I got everything up and going the customer thought warranty should cover it! I told him to call the guy in the pick up.
 

Joseph Marasco

Active Member
Joined
Dec 30, 2019
Messages
28
Location
Northeast NJ
Occupation
Heavy truck mechanic
I am a tech that often doesn't get the computer out until I have exhausted the other diagnostic processes. If there's a CEL, I'll start with the computer to point me in the right direction, but always trying to K.I.S.S.

I admit that I have wasted time with and without the help of the computer. Sometimes we can't see the forest for the trees.

Good thread, thanks everyone for contributing.
 
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