Slow Starting 5.9 Cummins
#3196236
12/09/23 12:18 PM
12/09/23 12:18 PM
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Joined: Feb 2005
Posts: 528
SW CO
HemiSportFury
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mopar
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OP
mopar
Joined: Feb 2005
Posts: 528
SW CO
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My 2003 5.9 Cummins HO is getting harder to start. I've owned it since new and it has 220,000 miles, about 90% highway, with about 20% of that towing. it's always had a stock tune. About two years I noticed it was getting a little slower to start. Instead of firing right off it might take six or seven revolutions to fire. Then a year ago it was taking significantly longer at times. I have gauges on it and the rail pressure was slow to build. It would fire as soon as it got to 1.5 kpsia. I replaced the relief valve since that is easy and no change. I then retorqued the cross tubes and that made it about 90% better. Now it's back to where it was. When I retorqued the cross tubes I was worried if it they had been leaking for some time that it might have cut a groove in the tubes or injector recess, so I'm not too surprised the problem came back.
So, the question is, what should I do now? Try retorquing the cross tubes again? Try new cross tubes? Or bite the bullet and replace the injectors along with the cross tubes? Once it builds 1.5kpsia it fires off quickly, no smoke, idles smooth and no change in fuel mileage. (I have been hand calculating the fuel mileage since it was new.)
I know that at 220,000 I'm on borrowed time on the original injectors, but if they don't need to be replaced, I can use the money elsewhere. If I do need injectors where is a good place to buy stock OEM injectors?
Any other advice? The batteries are new. (They aren't cheap either!)
Thanks for your help.
'64 Sport Fury, 528 Hemi, FiTech EFI, 4-speed, 4.10 Dana 60
'57 Belvedere 2dr sedan, current project in process
'19 Cherokee Trail Hawk Elite
'03 Ram 2500 CTD HO, 6-speed 214,000 miles and still going strong
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Re: Slow Starting 5.9 Cummins
[Re: Cab_Burge]
#3196320
12/09/23 06:43 PM
12/09/23 06:43 PM
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Joined: Feb 2005
Posts: 528
SW CO
HemiSportFury
OP
mopar
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OP
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If I was you I would put this on the truck forum if it is not on there now    I'll do that. Just more traffic on this one.
'64 Sport Fury, 528 Hemi, FiTech EFI, 4-speed, 4.10 Dana 60
'57 Belvedere 2dr sedan, current project in process
'19 Cherokee Trail Hawk Elite
'03 Ram 2500 CTD HO, 6-speed 214,000 miles and still going strong
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Re: Slow Starting 5.9 Cummins
[Re: A12]
#3196446
12/10/23 12:01 PM
12/10/23 12:01 PM
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Joined: Feb 2005
Posts: 528
SW CO
HemiSportFury
OP
mopar
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OP
mopar
Joined: Feb 2005
Posts: 528
SW CO
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No smoke on start-up and smooth idle so they can't be leaking too much into the cylinders, but high return rate a good possibility.
'64 Sport Fury, 528 Hemi, FiTech EFI, 4-speed, 4.10 Dana 60
'57 Belvedere 2dr sedan, current project in process
'19 Cherokee Trail Hawk Elite
'03 Ram 2500 CTD HO, 6-speed 214,000 miles and still going strong
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Re: Slow Starting 5.9 Cummins
[Re: HemiSportFury]
#3196651
12/11/23 11:42 AM
12/11/23 11:42 AM
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Joined: Jan 2003
Posts: 74,978
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 74,978
U.S.S.A.
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My 2003 5.9 Cummins HO is getting harder to start. I've owned it since new and it has 220,000 miles, about 90% highway, with about 20% of that towing. it's always had a stock tune. About two years I noticed it was getting a little slower to start. Instead of firing right off it might take six or seven revolutions to fire. Then a year ago it was taking significantly longer at times. I have gauges on it and the rail pressure was slow to build. It would fire as soon as it got to 1.5 kpsia. I replaced the relief valve since that is easy and no change. I then retorqued the cross tubes and that made it about 90% better. Now it's back to where it was. When I retorqued the cross tubes I was worried if it they had been leaking for some time that it might have cut a groove in the tubes or injector recess, so I'm not too surprised the problem came back.
So, the question is, what should I do now? Try retorquing the cross tubes again? Try new cross tubes? Or bite the bullet and replace the injectors along with the cross tubes? Once it builds 1.5kpsia it fires off quickly, no smoke, idles smooth and no change in fuel mileage. (I have been hand calculating the fuel mileage since it was new.)
I know that at 220,000 I'm on borrowed time on the original injectors, but if they don't need to be replaced, I can use the money elsewhere. If I do need injectors where is a good place to buy stock OEM injectors?
Any other advice? The batteries are new. (They aren't cheap either!)
Thanks for your help. I know nothing about the common rail engines , but I'm willing to learn in case I decide to swap my VP44 pumped 98 24V over. What builds that rail pressure , a lift pump , assuming it has one , or the Common rail CP pump , that may be your issue ?
running up my post count some more .
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Re: Slow Starting 5.9 Cummins
[Re: A12]
#3196732
12/11/23 03:48 PM
12/11/23 03:48 PM
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Joined: Jan 2003
Posts: 74,978
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 74,978
U.S.S.A.
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Just curious but I would assume it has a block heater of some sorts? Both a block heater and in place of glow plugs in the cylinder the ISB Cummins has a grid heater in the intake manifold , or incoming air path that warms the air when the outside temp is below a certian temp and untill the engine coolant reaches a certian temp and shuts off. The block heater warms the coolant and will run the grid heater for a shorter amount of time. I have my truck plugged in and on a timer and run it for about 2.5 hours in the morning which aids in quicker starting and faster coolant warm up.
running up my post count some more .
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Re: Slow Starting 5.9 Cummins
[Re: JohnRR]
#3196763
12/11/23 05:47 PM
12/11/23 05:47 PM
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Joined: Feb 2005
Posts: 528
SW CO
HemiSportFury
OP
mopar
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OP
mopar
Joined: Feb 2005
Posts: 528
SW CO
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[I know nothing about the common rail engines , but I'm willing to learn in case I decide to swap my VP44 pumped 98 24V over.
What builds that rail pressure , a lift pump , assuming it has one , or the Common rail CP pump , that may be your issue ? The lift pump supplies fuel to the CP, The CP is what makes rail pressure. In my case, the rail pressure is slow to build up the pressure the ECU needs to see to fire the injectors. As soon as it hits 1.5kpsia it starts instantly.
'64 Sport Fury, 528 Hemi, FiTech EFI, 4-speed, 4.10 Dana 60
'57 Belvedere 2dr sedan, current project in process
'19 Cherokee Trail Hawk Elite
'03 Ram 2500 CTD HO, 6-speed 214,000 miles and still going strong
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