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UPDATE: Hard starting Cummins ISM

Executive45
Explorer III
Explorer III
Good Morning everyone! Cummins ISM. 95,000 miles. Just had it serviced, replaced water separator, filters etc. including Allison transmission service. Generally used Speedco for service but tried out a new facility in Arizona. My engine has always started within 3-5 seconds, I'll call it a short crank. After service it will still start but it now takes a long crank. That's the best way I can describe it. I'm not used to cranking an engine for an extended period of time. What could be the cause? It appears they used the correct water separator when it was changed Racor RK12963. Any insight will be appreciated....Dennis
We can do more than we think we can, but most do less than we think we do
Dennis and Debi Fourteen Years Full Timing
Monaco Executive M-45PBQ Quad Slide
525HP Cummins ISM 6 Spd Allison
2014 Chevrolet Equinox LTZ W/ ReadyBrute
CLICK HERE TO VIEW OUR TRAVEL BLOG
15 REPLIES 15

Executive45
Explorer III
Explorer III
wildmanbaker wrote:
And I still like the "Low Rider" picture of your MH in your sig.


๐Ÿ™‚ Air leveling.
We can do more than we think we can, but most do less than we think we do
Dennis and Debi Fourteen Years Full Timing
Monaco Executive M-45PBQ Quad Slide
525HP Cummins ISM 6 Spd Allison
2014 Chevrolet Equinox LTZ W/ ReadyBrute
CLICK HERE TO VIEW OUR TRAVEL BLOG

wildmanbaker
Explorer
Explorer
And I still like the "Low Rider" picture of your MH in your sig.
Wildmanbaker

wildmanbaker
Explorer
Explorer
Yes, thanks for getting back with the results. As you know, not everybody does. You are a valued member of this Forum.
Wildmanbaker

2_many_2
Explorer III
Explorer III
Thank you for coming back with the results, congrats on an easy fix! :B

Executive45
Explorer III
Explorer III
Picked up the coach last night and it's fixed. When they put on the new filters one of the "O" rings didn't get seated correctly. Removed the filter, put on a new O ring and all is good again. Thanks everyone for your advice....Dennis
We can do more than we think we can, but most do less than we think we do
Dennis and Debi Fourteen Years Full Timing
Monaco Executive M-45PBQ Quad Slide
525HP Cummins ISM 6 Spd Allison
2014 Chevrolet Equinox LTZ W/ ReadyBrute
CLICK HERE TO VIEW OUR TRAVEL BLOG

Executive45
Explorer III
Explorer III
11178adm wrote:
the most likely cause is the wrong engine mounted fuel filter. The cummins N14, M11 and ISM engine fuel filter must have a metal tube down the center of the filter or they will have long crank time. There are a lot of filters that will screw onto the cummins filter base but whatever they installed should cross to fleetgard number FS1000


Thanks everyone again. After purging the system several times yesterday, I took the coach back to the shop this morning and advised them of the above and the other suggestions. They assured me they would fix it. I'm picking it up tomorrow and I'll post the results.

Thanks again for the sage advice....Dennis
We can do more than we think we can, but most do less than we think we do
Dennis and Debi Fourteen Years Full Timing
Monaco Executive M-45PBQ Quad Slide
525HP Cummins ISM 6 Spd Allison
2014 Chevrolet Equinox LTZ W/ ReadyBrute
CLICK HERE TO VIEW OUR TRAVEL BLOG

JackMS
Explorer
Explorer
If your separator is the type with the clear glass on top, there is usually an anti backflow valve in the outlet fitting. Very simple construction- a plastic cage with a ball and spring in it. Any bit of trash can cause a long crank situation, but it takes a while after shutting down to show up. If your engine is running and you shut it down and immediately restart, does it start better? If so then probably not that check valve.
2005 Holiday Rambler Neptune 34pdd, Cummins ISB 300, Allison 2500MH, Onan 8.0QD
Prior Toad-2001 Chevy 2500 CC 4WD
Toad-2012 Honda CRV, Blue Ox Aventa II

11178adm
Explorer
Explorer
the most likely cause is the wrong engine mounted fuel filter. The cummins N14, M11 and ISM engine fuel filter must have a metal tube down the center of the filter or they will have long crank time. There are a lot of filters that will screw onto the cummins filter base but whatever they installed should cross to fleetgard number FS1000

SidecarFlip
Explorer
Explorer
If it's a Racor, make sure the Tee handle is tight.
2015 Backpack SS1500
1997 Ford 7.3 OBS 4x4 CC LB

Executive45
Explorer III
Explorer III
Thanks everyone so far. You've verified my suspicions. Air somehow leaking back into the fuel was my initial thought. I've only driven it about 8 miles since the service..I;ll repurge the system today and see if that helps....Dennis
We can do more than we think we can, but most do less than we think we do
Dennis and Debi Fourteen Years Full Timing
Monaco Executive M-45PBQ Quad Slide
525HP Cummins ISM 6 Spd Allison
2014 Chevrolet Equinox LTZ W/ ReadyBrute
CLICK HERE TO VIEW OUR TRAVEL BLOG

wildmanbaker
Explorer
Explorer
Contact the shop and voice you concerns after the service. There may be a small leak allowing air into the fuel line.
Wildmanbaker

grldst
Explorer
Explorer
Are you using the water separator with the clear bowl on the bottom? Some installers get confused as to proper installation of seals on these.

Bird_Freak
Explorer II
Explorer II
Sounds like air in the fuel system. Maybe a bad seal on filter.
Eddie
03 Fleetwood Pride, 36-5L
04 Ford F-250 Superduty
15K Pullrite Superglide
Old coach 04 Pace Arrow 37C with brakes sometimes.
Owner- The Toy Shop-
Auto Restoration and Customs 32 years. Retired by a stroke!
We love 56 T-Birds

JaxDad
Explorer III
Explorer III
Typically a longer crank to start after a service would indicate you still have some air in the system. Unusual on a newer diesel, but not unheard of.

How far / long have you driven it since the service was done?