hard starting
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From: Quincy IL.
hard starting
i have a 96 5.9 deisel with around 118 thousand miles on it it is getting hard to start seems i have to recycle the wait to start light several times and even then it dont always start the local dodge dealer said it was probaly the lift pump is that the same as fuel transfer pump im new to this please someone help there is another shop that i talked to about ordering a lift pump for me they did i just want to know will this cure my problem help please
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Re:hard starting
Rarely is the lift pump (same as the transfer pump) the cause of hard starting on a 96, but it is easy to check.
Reach down beside the engine block, below the upper fuel filter and right beside the fuel heater/prefilter, and you will find the lift pump mounted to the left (driver's) side of the engine block. It has a rubber bulb that covers the piston follower for the lift pump. That is the primer, and give it a few pushes. If it is hard to push, it is doubtful the lift pump is the problem. If it pushes real easy, or you get fuel on you hands, it is time for a change. Go to a Cummins Service Center and get the replacement pump, or have them do the service.
The most common problem with hard starting is air in the fuel from old fuel lines. The soft hoses should be changed every few years, and a lot of people do not change them until the rig gets hard to start. Replacement hoses can be had at most diesel truck repair shops, or marine service centers that work on diesel boats, and they are 3/8 id on the feed side, and 5/16 id on the return lines. When you replace them, use the OEM style compression clamps, not airplane (screw type) or they will leak air at the junctions in a few months after the hose takes a set. There are two pairs of feed and return line hoses, one from the frame to the engine, and the other set is from the tank to the hard lines on the frame.
While you are at it, and have the fuel system open anyway, replace the screen and gaskets in the fuel heater, and check the connection to the wire for the heater for an air leak (the best way is to unplug the connection, fill it with dielectric grease, and replug the wire to the body of the unit). Also, replace your primary fuel filter (the one on top), and check the water detector (the plastic housing on the primary filter) for any cracks.
The next item to service is the overflow valve. It is a little fitting located in the valley between the injection pump and the head, and has the fuel return hose (the 5/16 id one that should be replaced as routine PM every few years). The valve should be routinely replaced after about a 100,000 miles, and get the new one from Cummins, not Dodge.
Some of the engines do not have enough clearance to remove the overflow valve without grinding away a bit of the engine head where it gets in the way. If you need to do that, be sure your fuel system is completely closed before you grind. Then use brake cleaner to clean all grindings away before you open the fuel system. The least bit of dirt will damage the system.
The hardest part of fuel system maintenance is repriming the system. The little fuel primer, located on the lift pump, is a real pain in the backside to get it pumped enough to completely reprime the system. If the overflow valve is the least bit worn, you can pump your fingers off and it will take about an hour to get everything primed. If the overflow valve is in good shape, a few pumps to get fuel to the injection pump, and then cranking on the starter will generally get them primed in a fifteen minutes or less. You can also sometimes get air in the injectors, and have to bleed them during this process.
It all sounds rather daunting, but it is not. Just take your time and be absolutely certain there is no dirt or dust near any open fuel system components.
If you are mechanically inclined, and do not already have a service manual, get the Haynes Manual #30041, about $15, and it has real good instructions on the work needed.
If you are not into grease and wrenches, it is my experience that Cummins will be way less expensive for both parts and labor than the Dodge dealer. The Cummins mechanics are also trained and experienced in the work, and most Dodge dealer service departments do not work on enough of the 12 valve diesels to have well experienced technicians.
Reach down beside the engine block, below the upper fuel filter and right beside the fuel heater/prefilter, and you will find the lift pump mounted to the left (driver's) side of the engine block. It has a rubber bulb that covers the piston follower for the lift pump. That is the primer, and give it a few pushes. If it is hard to push, it is doubtful the lift pump is the problem. If it pushes real easy, or you get fuel on you hands, it is time for a change. Go to a Cummins Service Center and get the replacement pump, or have them do the service.
The most common problem with hard starting is air in the fuel from old fuel lines. The soft hoses should be changed every few years, and a lot of people do not change them until the rig gets hard to start. Replacement hoses can be had at most diesel truck repair shops, or marine service centers that work on diesel boats, and they are 3/8 id on the feed side, and 5/16 id on the return lines. When you replace them, use the OEM style compression clamps, not airplane (screw type) or they will leak air at the junctions in a few months after the hose takes a set. There are two pairs of feed and return line hoses, one from the frame to the engine, and the other set is from the tank to the hard lines on the frame.
While you are at it, and have the fuel system open anyway, replace the screen and gaskets in the fuel heater, and check the connection to the wire for the heater for an air leak (the best way is to unplug the connection, fill it with dielectric grease, and replug the wire to the body of the unit). Also, replace your primary fuel filter (the one on top), and check the water detector (the plastic housing on the primary filter) for any cracks.
The next item to service is the overflow valve. It is a little fitting located in the valley between the injection pump and the head, and has the fuel return hose (the 5/16 id one that should be replaced as routine PM every few years). The valve should be routinely replaced after about a 100,000 miles, and get the new one from Cummins, not Dodge.
Some of the engines do not have enough clearance to remove the overflow valve without grinding away a bit of the engine head where it gets in the way. If you need to do that, be sure your fuel system is completely closed before you grind. Then use brake cleaner to clean all grindings away before you open the fuel system. The least bit of dirt will damage the system.
The hardest part of fuel system maintenance is repriming the system. The little fuel primer, located on the lift pump, is a real pain in the backside to get it pumped enough to completely reprime the system. If the overflow valve is the least bit worn, you can pump your fingers off and it will take about an hour to get everything primed. If the overflow valve is in good shape, a few pumps to get fuel to the injection pump, and then cranking on the starter will generally get them primed in a fifteen minutes or less. You can also sometimes get air in the injectors, and have to bleed them during this process.
It all sounds rather daunting, but it is not. Just take your time and be absolutely certain there is no dirt or dust near any open fuel system components.
If you are mechanically inclined, and do not already have a service manual, get the Haynes Manual #30041, about $15, and it has real good instructions on the work needed.
If you are not into grease and wrenches, it is my experience that Cummins will be way less expensive for both parts and labor than the Dodge dealer. The Cummins mechanics are also trained and experienced in the work, and most Dodge dealer service departments do not work on enough of the 12 valve diesels to have well experienced technicians.
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Joined: Apr 2002
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From: MidWest
Re:hard starting
Im certainly no expert here, but I thought the pre-24 valves had a mechanical lift pump. I havent heard of too many mechanical lift pumps going bad. BUT, thats not to say they dont.
Things you might want to check (Or have the dealer check for you) is:
1) Check fuel return lines for cracks/leaks.
There is a rubber fuel return line that is hard to get to. This line (being rubber) can often crack and leak. This can cause a loss of prime and may cause hard starting.
2) Check the condition of the heater grid and the wiring going to the heater grid.
Wire connections can come lose/corrode and the grids do need to be replaced from time to time.
3) Have you replaced your fuel filter?
4) Hows the condition of your batteries/starter and all the associated wiring there? Does your starter crank the engine fast enough?
These are just a few places to start looking. No guarantees that any of the above is the problem... just a place to start.
Good luck
Rich.
Things you might want to check (Or have the dealer check for you) is:
1) Check fuel return lines for cracks/leaks.
There is a rubber fuel return line that is hard to get to. This line (being rubber) can often crack and leak. This can cause a loss of prime and may cause hard starting.
2) Check the condition of the heater grid and the wiring going to the heater grid.
Wire connections can come lose/corrode and the grids do need to be replaced from time to time.
3) Have you replaced your fuel filter?
4) Hows the condition of your batteries/starter and all the associated wiring there? Does your starter crank the engine fast enough?
These are just a few places to start looking. No guarantees that any of the above is the problem... just a place to start.
Good luck
Rich.
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