Hard Starting 2003 common rail Cummins ???

G Anderson · 07-08-2014, 05:32 PM

I have a 2003 Dodge with a 5.9 Cummins 223k miles It has recently become hard to start 20-30 seconds of cranking ! But when it starts it runs just fine. Just don't shut it off-or it will continue to have starting issues. Everything I read on line says 1 or more bad injectors. Are there any other possibilitys ,such as cam or crank sensor or maybe rail pressure sensor ? Any help would be appreciated. Thanks Greg

Rob Petrie E395 · 07-08-2014, 08:37 PM

Try taking the line off of the relief valve and cranking it. During cranking NO fuel should bubble out. If it does bubble out it means the valve is not sealing properly and that causes it to not build pressure fast enough to start. If you have a gauge you can check it that way too but most guys dont that is why I suggest what I wrote above.. Should build to 6K pretty quick it needs 4k start.

Chipper Chapman · 07-24-2014, 02:10 AM

I second whats stated above. Have seen many that the pressure relief on end of rail will get hung open a fraction by foreign material, usually shortly after a fuel system repair.

Run to Rund · 07-24-2014, 08:45 AM

A big reason why these common rail systems need new injectors and sometimes the pressure relief valve is that Bosch wanted 4 micron or better fuel filtration, but such filters weren't readily available until a couple years ago. The Rams came with 10 micron filtration, and later 7 micron was made available. Commercial diesel fuel in this country often has up to 15 micron particulates.

07-08-2014, 05:32 PM	#1
G Anderson Member Join Date: Dec 2009 Location: Iowa Posts: 103 Likes: 12 Liked 3 Times in 2 Posts	Hard Starting 2003 common rail Cummins ??? I have a 2003 Dodge with a 5.9 Cummins 223k miles It has recently become hard to start 20-30 seconds of cranking ! But when it starts it runs just fine. Just don't shut it off-or it will continue to have starting issues. Everything I read on line says 1 or more bad injectors. Are there any other possibilitys ,such as cam or crank sensor or maybe rail pressure sensor ? Any help would be appreciated. Thanks Greg

07-08-2014, 08:37 PM	#2
Rob Petrie E395 VIP Member Join Date: Dec 2007 Location: Woodlawn IL Posts: 1,093 Likes: 162 Liked 219 Times in 79 Posts	Re: Hard Starting 2003 common rail Cummins ??? Try taking the line off of the relief valve and cranking it. During cranking NO fuel should bubble out. If it does bubble out it means the valve is not sealing properly and that causes it to not build pressure fast enough to start. If you have a gauge you can check it that way too but most guys dont that is why I suggest what I wrote above.. Should build to 6K pretty quick it needs 4k start.

07-24-2014, 02:10 AM	#3
Chipper Chapman Member Join Date: Jan 2004 Location: Belmont N.S. Canada Posts: 452 Likes: 211 Liked 141 Times in 63 Posts	Re: Hard Starting 2003 common rail Cummins ??? I second whats stated above. Have seen many that the pressure relief on end of rail will get hung open a fraction by foreign material, usually shortly after a fuel system repair. __________________ Chris Chapman 1969 Chevelle NHRA F-G/SA 1090

07-24-2014, 08:45 AM	#4
Run to Rund Senior Member Join Date: Sep 2007 Posts: 574 Likes: 6 Liked 44 Times in 22 Posts	Re: Hard Starting 2003 common rail Cummins ??? A big reason why these common rail systems need new injectors and sometimes the pressure relief valve is that Bosch wanted 4 micron or better fuel filtration, but such filters weren't readily available until a couple years ago. The Rams came with 10 micron filtration, and later 7 micron was made available. Commercial diesel fuel in this country often has up to 15 micron particulates.