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dsalinas1939
Top Member
USA
1324 Posts |
 Posted - 05/16/2022 : 06:33:50 AM
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| 2014 c2 cummins 6.7 isb getting a code 4691 and every once and a while the driver states bus will crank and crank and wont stsrt anf finally after a few time if long crank it fires up now everytime they bring it in to shop i have no problems starting i have takin it out for long rides shut it down it fires right up i let it sit over night next moring its fine i am thinkin its a lift pump problems any thoughts |
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Bluenozer
Top Member
Canada
644 Posts |
Posted - 05/17/2022 : 03:04:11 AM
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if you do the fuel pressure test with INSITE , does it reach 24,000 psi every time , could be dirt holding pressure valve in rail open, and after a while the fuel washes it out and valve closes and unit starts, never seen an electric lift pump on a ISB before( they can be spec with on) , but with an ISC if you hear it turn on with key then it is working, 10 psi I think is pump output if yours is equipped , injectors and pump usually when they go bad there is no coming back
was work done on fuel system recently , red paint flakes can hold the valve open seen it alot , no one cracks the lines then use a blow gun to remove loose paint |
OEM trained in wiring and all engine platforms for over 20 years
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dsalinas1939
Top Member
USA
1324 Posts |
Posted - 05/17/2022 : 04:53:39 AM
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| there was no work done to this bus or to the fuel system resently and when i did the test it was always over 24000 it went as low as 244000 and hi 247000 i no what u mean about the paint i always try and blow those chips out it flakes off everywhere. but like i said its been running great all day yesturday i drove it around alot let it sit for half hour when out started right up it happens so rarely at least once week but the driver says it will always eventuall start afrter two or three trys |
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Bluenozer
Top Member
Canada
644 Posts |
Posted - 05/17/2022 : 08:46:11 AM
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| i just used the red paint as an example, could be any kind of dirt, is the tank full, empty, just got filled when this happens , most of our fleet fuels up once a week at least |
OEM trained in wiring and all engine platforms for over 20 years
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dsalinas1939
Top Member
USA
1324 Posts |
Posted - 05/19/2022 : 05:38:34 AM
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| its happened fuel its happened half tank they usually fill up every other day |
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c2 code 4691
