The Cummins diesel is a longevity engine. When serviced properly, the engine should last 500,000 to a million miles between teardowns. Peripherals like the turbocharger, fuel injectors and the fuel pump, however, can wear out or fail much earlier.
A well maintained fuel system can keep injectors going for 250,000 miles or more. The original common rail diesel injectors and CP3 pump in my 2005 Ram have been trouble free for 180,000 miles now. These injectors have delivered good performance and fuel efficiency. There are no signs of spray pattern issues, fuel surging or leakage.
Long injector life depends upon adequate fuel supply, quality fuel filtration and clean injector components. In addition to routine fuel filter changes, I periodically clean the fuel system. Purging the high pressure pump and injectors helps maintain peak performance and reliability.
When symptoms of wear, leakage or a fault code point to injector trouble, the injectors should be bench tested on a Bosch test stand. If pilot injection, full load flow or the volume of return fuel fails during this test, the injector needs precision rebuilding or replacement with a new unit.
Many shops and owners prefer genuine Mopar, Cummins or Bosch new or remanufactured injectors. A full set of new injectors may also provide a design upgrade, perhaps better durability or performance than the original injectors. In any case, a full set of new Bosch injectors will be costly.
Early symptoms of injector failure include rough starting and cold idling or surging from poor sealing and fuel pooling. There may be a lack of power or more black smoke than normal. If an injector is defective, routine service will not improve performance.
Inadequate or faulty fuel filtration or lift pump troubles can quickly damage the high pressure pump or injectors. If contaminated fuel or water gets past the fuel filter, the high pressure pump and injectors are at risk. Change the fuel filter routinely to preserve the pump and injectors. Do not allow debris to fall into the filter canister when changing the fuel filter. Make sure the filter seals properly.
Pump and Injector Preventive Care
Although I use and recommend certain products for flushing and cleaning the fuel system, there is no substitute for fuel injector bench testing. If symptoms of a defective injector or a Check Engine code indicate a more serious injector problem, consider bench testing the injectors. The injectors should be tested on a Bosch EPS205 or equivalent machine for the rate of fuel return, pressure readings, leaks, fuel dripping at the nozzles and spray patterns. Severe engine damage can result from running with a leaky injector. A bad spray pattern that does not atomize fuel properly can etch away a piston crown.
Unless a Bosch injector is defective, injectors can be cleaned without removing parts. For purging contaminants and debris from the high pressure pump and injectors, I flush the injection system with Sea Foam Motor Treatment. One flushing method is no more difficult than changing the fuel filter. The other method involves use of an SUR&R (surrauto.com) part number FIC203 Fuel Injection Cleaner Kit.
I use the following steps on my 5.9HPCR engine (2004.5-2007). Determine which Sea Foam delivery method will work best for your truck’s fuel system and diesel injection type. With either service method (add product into fuel filter canister or add product from FIC203 kit), the engine will idle and run unloaded on pure Sea Foam Motor Treatment.
Fuel Filter Canister Cleaning Method
The fuel filter gets replaced routinely. For the simpler service method, warm the engine then shut it off. Carefully drain the fuel filter canister while avoiding engine heat and hot surfaces. Use a safe drain pan or container. Keep fuel away from heat.
My service technique: Prime the fuel system and start the engine. Run the engine for 60-90 seconds before shutting it down. This allows the Sea Foam Motor Treatment to run through the pump, injection system, and combustion areas. After a 20-minute heat soak, restart the engine. Allow oil pressure to normalize then take the truck for a run under heavier throttle.
I change the engine oil and filter after performing this service. At each fuel fill-up, Sea Foam Motor Treatment gets added to the main fuel tank. The auxiliary fuel tank gets an occasional dose as well. Although no cleaning or maintenance will prevent pump or injector wear, preventive care like this can extend parts life and improve both performance and fuel efficiency.
Ford: Diesel Injector “Stiction”
The buzzword “stiction” (“static” plus “friction”) has become popular in diesel forums. Fortunately, it is not a significant Cummins issue. The term applies primarily to the HEUI style diesel fuel injectors used in Power Stroke Ford 7.3 and 6.0-liter, Navistar-built engines.
Ford Power Stroke stiction issues have spawned a number of aftermarket fuel and crankcase additives. The HEUI injectors would benefit from either of the injector cleaning methods that I use on my truck. Equally important would be keeping the HEUI oil pressurized components clean and minimizing engine oil gum, sludge, oil breakdown and static/friction issues.
Ram: A Brief Look at Injectors
Fortunately for Ram owners, Bosch fuel injectors (from the 12 and 24-valve engines with mechanical injectors to today’s solenoid actuated HPCR 5.9 and 6.7 engines) do not use pressurized engine oil to boost the fuel pressure. The Cummins HPCR fuel pump and injectors are capable of higher fuel injection pressures than Ford’s HEUI injectors.
Mechanically actuated 1989-2002 injectors are reliable and easier to service. Precisely timed, highly pressurized fuel forces open the spring counter-weighted injector needle. Fuel flows from the nozzle. While internal pieces can stick, this is less likely given that diesel fuel has a degree of lubricating ability. These mechanical injectors generally fail from overuse, broken or binding parts, corrosion and severe pitting or leaks. Until that point, they can benefit from periodic flushing.
With these injectors, fuel dripping and lower needle or nozzle opening pressures are signs of a weak spring, needle and nozzle damage or worn seats. This shows up during injector bench tests as leakage, early fuel flow or drip and an improper nozzle spray pattern. A poor spray pattern always means incomplete fuel atomization. Be aware that when any mechanical or electro-magnetic injector stops atomizing fuel properly, severe engine damage can result. This includes piston or cylinder head failure.
High pressure, common rail injectors (2003-current) use a heavy duty electro-magnet (solenoid) with a spring balanced check ball system. There is also a spring balanced servo piston and nozzle. The injectors rely upon high pressure injection pump pressure. Fuel injector failure is the result of mechanical wear, a cracked housing, pitted nozzle, corrosion, a solenoid armature short or internal sealing issues.
Though often difficult to control, the quality of fuel can be a large contributing factor when injectors fail. Ultra low sulfur diesel (ULSD) fuel has less lubricity and is hygroscopic. Diesel fuel will also draw moisture from the atmosphere and drag it through the fuel system. This is an additional load on the injectors.
Water promotes injector corrosion, and lack of lubricity can lead to seal failure. Poor fuel lubricity can also cause expensive, even catastrophic pump damage. Quality fuel filtration is the best defense against water. Mopar/Cummins NanoNet fuel filters are your best protection.
The SUR&R FIC203 Fuel Injection Cleaning Method
For a more thorough cleaning, the SUR&R FIC203 Fuel Injection Cleaning Kit bypasses the truck’s diesel fuel supply. Remote canister cleaning is popular with repair shops, fleet operators and do-it-yourself home mechanics. Once a year, I use the SUR&R kit, idling and heat soaking the engine with two 16-ounce cans of pure Sea Foam.
SUR&R makes a variety of automotive service tools for shops and serious DIY enthusiasts. The company is now a subsidiary of Husky Corporation, the manufacturer of commercial fuel nozzles. Among the many useful tools and products are the SUR&R fuel injection testing and cleaning kits for gasoline and diesel engines.
Clean compressed air pressurizes the FIC203 canister, delivering fuel just like the OEM fuel tank pump. The remote canister’s adjustable air regulator can be set to the same pressure as the OEM fuel tank pump. The engine fuels directly from the FIC203 canister, and the OEM fuel pump is temporarily off line. With this system, the excess volume of fuel returns to the fuel tank. Any Sea Foam Motor Treatment returning to the fuel tank will help keep the fuel injection system clean while driving.
The engine should be warmed before starting this procedure. Use a suitable catch pan and open the drain valve at the fuel filter canister. Drain the fuel from the filter canister. Keep away from engine heat and disconnect the fuel supply line at the filter canister.
Once the tank pump or lift pump has been disabled, I disconnect the fuel supply line at the fuel filter canister. The correct FIC203 adapter hose attaches at the canister supply pipe. A long connecting hose attaches to the FIC203 fuel canister. If the fuel filter needs replacing, do so now.
Start the engine. When the canister of Sea Foam is nearly empty, the engine idle will begin to roughen. Shut off the key before the fuel canister runs dry or the engine dies. This is especially important on earlier engines with mechanical fuel injectors. Running the engine dry may require injector line bleeding for a restart.
By now, pure Sea Foam has run through the high pressure pump, injectors and combustion areas. Sea Foam recommends heat soaking the injectors and upper engine for twenty minutes. This can be done while refilling the FIC203 canister with a second can of Sea Foam Motor Treatment. After the heat soaking, restart the engine. Idle the engine until the second canister of Sea Foam is nearly empty. Again, listen for the first sign of a low fuel supply. Before the engine starves for fuel and dies completely, shut the key off.
Unhook the FIC203 canister, hose and adapter. Hook the OEM fuel supply line back up. I install a new plastic coupler fitting when reattaching the supply line at the OEM fuel filter canister. This is cheap insurance against a fuel leak.
Be certain to rotate and seat the retaining clip fully into the coupler before sliding the coupler onto the pipe. If the clip aligns properly, the hose coupler will click into place with only slight resistance. Forcing the hose coupler will create a leak or damage the expensive factory hose and pipe assembly. The goal is to install the retainer clip properly within the coupler.
Reinstall the fuel pump fuse at the fuse box. Before starting the engine, prime the fuel system to bring tank fuel to the canister and purge air from the supply lines. Priming the fuel supply system is not difficult on my truck (a 2005) with the in-tank electric fuel pump. The bump-key method works well here: 1) gently bump the key to the crank position just enough to rotate the crankshaft slightly without allowing the engine to start; 2) release the key to the ON position, and this will run the fuel pump for twenty-five seconds; 3) turn the key off then turn the key back ON and gently bump the key to the crank position; 4) again release the key to the ON position.
Each time you perform this cycle, the bump method will run the low pressure fuel pump without starting the engine. When primed, try starting the engine. If it fails to start, turn the key off and wait for at least five seconds. Repeat the priming process until enough air is purged from fuel lines.
When the engine starts, it may run roughly for a moment. Once the engine reaches normal oil pressure and stabilizes, give the truck a good run under heavier throttle. The MIL/Check Engine lamp will likely be lit. Don’t panic. This diagnostic trouble code (DTC) is from running the engine with the fuel pump fuse removed during the FIC203 cleaning process.
This preventive maintenance routine has kept my truck reliable and minimized expenses. That’s not bad for a fifteen year old truck.
For more details on Sea Foam Motor Treatment:
For more details on SUR&R Tools:
TDR note: Back in the earlier days of May Madness there was a seminar where the Concrete Cowboy (me) would have a lively discussion with the Rancher Dude (John Holmes). The back-and-forth banter over how to do this and how to do that was lively and entertaining. The bottom line(s): There is more than one way to maintain a truck and we both wanted the best for our vehicles.
To this day the Concrete Cowboy orders a Tradesman truck and spends countless hours (and dollars) making it into the Laramie trim that the Rancher Dude orders direct from the factory.
How does this relate to the “Long Haul” story? The Concrete Cowboy has never done any injector/fuel system maintenance or cleaning. On the other side of the ledger, Moses does the injector cleaning once a year.
Your truck, your choice: the writing staff tries to bring you both sides.
This article originally appeared in TDR Issue 108, May/June/July 2020.