First, I must credit everyone who has contributed, while maybe not directly, but by sharing their knowledge so that I could read it and compile it here. These individuals can be found on the forums of several sites on the web, including Diesel Truck Resource, DieselRam.com, Diesel Central, Turbo Diesel Register, DodgeRam.org, and others.
If you have a 1998.5-2002 24 valve Cummins, the very first thing you should
do is check the fuel pressure. The 24v engine are infamous for eating fuel
pumps. Most people you talk to on any of the above mentioned forum sites will
tell you that if you do nothing else, install a fuel pressure gauge to keep an
eye on it. You should have 6 or more pounds of pressure at full throttle and
12-15 at idle. If lower, and you still have warranty, go see the dealer.
Note: warranty in this case means the Cummins warranty, not Dodge's, and
it goes for 5 years/100,000 miles. The Dodge dealer still fulfills the warranty
though. I have also heard that a Cummins dealer will fix it under warranty also.
The large number of fuel pump failures has not been traced to any one specific thing. Some truck go 100,000+ miles and never need one, but I have heard of others having 3 pumps put on before 20,000. Some trucks keep on running even when the fuel pump has failed. More on that in the Case Study below.
Most brake troubleshooting information is standard for any brake system, but there are a few specific things that affect Dodge trucks. Many are documented in TSBs (Technical Service Bulletins), which the people at DodgeRam.org have done a great job of compiling.
This is the most likely cause of the lift pump failures, although the pump's location is still a contributing factor. The banjo bolts are bolts connecting the fuel line to the fuel pump, fuel filter, and injector pump. These bolts have holes down the center of them and a hole cross-drilled across the diameter, just below the head. The stock bolts have the cross-drilled hole sized at .130, just over 1/8 of an inch. In theory, the restrictive holes cause the fuel to not be able to flow as well as it probably should, and subsequently, causes the fuel pump to work harder.
First a little about electric fuel pumps. Due to physics of pump design, electric fuel pumps tend to want to push fuel rather than pull it, like a mechanical fuel pump. This is because the mechanical pumps use a big rubber diaphragm and electric fuel pumps generally use a vane type impeller. Examples of electric fuel pump usage can typically be seen at the drag strip, where you will see all of the electric fuel pumps mounted very close to, if not inside of, the fuel tank, and one the same level or lower. Most fuel injected gas engines have the pump in the tank as well. Examples of this could go on forever, such as well pumps. All newer well pumps are submersible because they can push the water better than they can pull it.
The fuel pump on the 24v Cummins is mounted on the engine, no where near the fuel tank. I have heard a rumor that Cummins recommended Dodge put the fuel pump near the tank and Dodge refused. I have not, however, been able to verify this so I can't say it's true although I believe it's likely.
So now you have a fuel pump that's doing a lot of sucking, which it would rather not do.
The really bad part here is not that you will be stranded on the side of the road when the fuel pump goes bad, but the affect it has on the injector pump. The Bosch VP-44 injector pump used on the 24v Cummins Turbo Diesel is unlike the earlier 12 valve's injector pump in that it is not lubricated and cooled by motor oil. The VP-44 is lubricated and cooled by the diesel fuel circulating through it as it fuels the engine. This makes the fuel pump's job even more critical because if it does not circulate enough fuel to power the engine in all conditions, and push enough extra fuel through the injector pump to satisfy its lubrication and cooling needs, you may effectively fry the injector pump on the engine.
First, bigger banjo bolts, which should help, but does not guarantee your pump will not fail, is aftermarket banjo bolts, with larger holes in them. The aftermarket bolts have holes drilled from .187 to .190, giving them better flow and relieving some of the pressure between the pump head and the destination, the filter filter and into the injector pump.
I will boldly state that Banjo bolt replacements, with the larger holes, would be money well spent, since they only cost 25-35.00. While it is not a guarantee, it is the cheapest measure you can take as preventative action.
Also, you can relocate the fuel pump to a more suitable location, near the fuel tank. This will require some fabrication of fuel lines, depending on how much of them you replace, mounting an aftermarket fuel pump, and wiring it.
Don't think that just because your engine is running you don't have a fuel pressure problem. Let me share an experience with my 1999 2500. I bought it with 47,000 on it. The 1999 has 2 plugs on top of the fuel filter which can be removed to test fuel pressure. Soon after I purchased my truck, used, and learned of the importance of checking the fuel pressure, I removed one plug to connect a temporary gauge to see what my fuel pressure was. When I attempted to fire up the truck with the gauge attached, I heard the electric fuel pump humming, but no fuel pressure. Zero. Now the truck wouldn't start either. It seems I disturbed the vacuum in the fuel system that was keeping the fuel flowing. It was replaced under the Cummins warranty.
Note: the VP-44 has a small amount of suction which will allow it to keep fueling the truck if the fuel pump stops functioning properly. This is what happened in my case, but I don't know how long the injector pump was being starved for the lubricating and cooling bypass fuel. This could have caused damage to my injector pump that may or may not affect it down the road. I will stress that failed fuel pumps have been the cause for failure of injector pumps. This is a known, undisputed fact.
In this case, I was lucky, or unlucky, depending on how you look at it. Where some trucks don't run when their fuel pump stops working, mine did run with a bad pump on it. I'd rather the truck stop running immediately when the fuel pump failed, instead of running around potentially damaging my injector pump for who knows how long.
If you see mistakes or omissions on this page please let me know: Me (at) Stamey.nu.