The 7.3 Powerstroke is commonly referred to as the “Legendary 7.3”. Outside of being the largest diesel engine ever put into high-production, consumer-grade trucks, it is also widely considered the 2nd most reliable diesel ever produced. It is no doubt the most reliable Powerstroke ever produced.
Known to be one of the most over-built diesel motors, there is no wonder Ford ended up producing nearly 2.5 million 7.3 Powerstrokes by the time it was retired. However, the beast of a diesel engine is still prone to its share of issues including the cam position sensor, fuel filter housing, up pipes, and a few others.
I’ve owned a 7.3 F350 for a number of years now. In this article, I discuss some of the most common Ford 7.3 PowerStroke engine problems in-depth and provide my thoughts on overall reliability based on issues I’ve experienced first hand.
7.3 Powerstroke Engine Problems
- Camshaft Position Sensor Failure
- Leaking Fuel Filter Housing
- Turbocharger Up-Pipe Leaks
- Bent Push Rods / Valve Springs
- Exhaust Back-Pressure Valve Failure (EBPV)
- Under Valve Cover Harness (UVCH)
- Injection Pressure Regulator (IPR) Failure
If you would rather consume this content via a video, check out our 7.3 Powerstroke Common Problems video below or on YouTube:
7.3 Front-End Suspension
This is an engine problem post, not a suspension post. But I wanted to mention that the front end on these F250/F350 Super Dutys requires a bit more maintenance compared to other trucks. It likely has something to do with how massive and heavy the engine is, creating a bit of extra wear and tear. Bushings, ball joints, tie rods, and all those other fun small but important suspension components do wear out. Including the steering gearbox, which you can read about here.
1. Camshaft Position Sensor (CPS) Failure
The CPS sensor sits on the bottom half of the engine block, slightly above the crankshaft damper, and controls both the camshaft position and speed, and relays this information to the Powerstroke’s computer or PCM. The engine’s computer uses the camshaft positioning data from the sensor to adjust fueling to deliver adequate fuel levels at the right time to control engine timing.
The CPS on the 7.3 is widely known to be the most common or most frequent failure point on these engines. The PCM uses the CPS signal to then signal the injector driver module to tell it how much fuel to deliver to which cylinder. When the sensor fails, the PCM doesn’t get a signal and therefore won’t send a signal to the IDM to tell it to deliver fuel. The end result is your 7.3 not getting the fuel that it needs to start the engine or continue running.
While has gone through a number of design revisions over the years, it still remains a common failure point. Owners have had the most success with the most recently released dark grey and purple CPS sensor. At just $23, we recommend buying a 2nd one and keeping it in your glovebox in case your CPS fails while you are on the road or on a trip. Replacing the sensor is super easy so it doesn’t make sense to risk getting stranded and having to pay for a tow.
CPS Failure Symptoms
- Engine cranks but won’t start
- Rough acceleration and poor idling
- Check engine light (code P0284 and more)
- Engine stalls during idle or randomly while driving
2. Leaking Fuel Filter Housing
The fuel filter housing, also commonly referred to as the fuel bowl, is prone to developing cracks and causing fuel leaks. While the pump itself is made of aluminum, the cap for it is made of plastic. The pressure of the fuel system combined with the heat from the engine bay can cause the cap to wear over time or develop cracks that can spew and leak fuel. Poor quality aftermarket fuel filter caps are most prone to cracking and leaking. While it is somewhat less common, we have seen cracks in the aluminum housing itself before, but it is rather rare.
Outside of a cracked cap, the o-rings are a common cause of a leaking fuel filter housing as well. The chemicals in diesel fuel are thought to not play well with the coating that Ford uses on the o-rings and oil seals. The chemicals can create gaps around the o-rings that fuel can then slip past. The O-rings on the drain valve are known to crack in colder weather, causing leaks.
A third potential cause is tightening the fuel cap too tightly which distorts the o-ring and causes a slow drip from the cap.
Leaking Fuel Filter Symptoms
- Fuel dripping under the vehicle
- Slow cranking
- Engine stalls during idle
- Fuse can blow causing no start
3. Turbocharger Up-Pipe Leaks
The turbo up-pipes are a part of the 7.3’s exhaust system, connecting from the exhaust manifold to the turbocharger. The factory pipes have what are called crush donut gaskets to connect the pipe to the manifold and turbo. As exhaust gasses continually flow through, the piping expands and contracts. Over time, this expansion and contraction leads to the crush gaskets deteriorating and beginning to leak.
Symptoms of Leaking Up-Pipes
- Decreased performance
- Loss of acceleration
- Increase exhaust gas temps
- Decreased fuel engine
- Diesel particulate/soot on the back of the engine, firewall, and tranny
Due to the likelihood of the OEM up-pipes leaking, most folks will opt for upgraded up-pipes once their OEM set fails. Upgraded piping will have stronger gaskets, preventing leaks. Additionally, upgrading this part can help increase the exhaust sound and deep tones of the exhaust system. An upgrade kit is a great option for those looking to replace their pipes without adding too much additional exhaust noise at a great price point.
4. Bent Push Rods / Valve Springs
While two separate problems, bent push rods and failed valve springs tend to go hand in hand. Valve springs are responsible for making sure the valvetrain opens and closes smoothly and making sure the lifter remains in contact with the camshaft. The springs themselves do not have a high seat pressure which can cause valve float at high RPMs. Essentially, when the spring pressure is too low, at high RPMs it can “float” or cause the valves to not fully seal.
You will likely hear some noises from the engine, get a low compression test in a cylinder, or cause some more serious engine damage. If the spring breaks rather than simply floating, it can send the valve into the cylinder which will damage the piston, cylinder head, and other internal engine components.
Pushrods commonly fail due to a weak cylinder, which can be caused by valve spring issues. Additionally, stuck lifters, poor engine timing, and rocker arms that are too tight can also cause this issue. Engines running above stock horsepower will put extra stress on the push rods and valve springs which can cause them to bend. If you are running aggressive power and increased fueling, it is recommended to upgrade to performance springs and rods capable of handling the additional power.
5. Exhaust Back-Pressure Valve (EBPV) Failure
The EBPV is a Y-shaped valve that is mounted to the outlet of the turbocharger. The back pressure valve is controlled by an actuator which also sits attached to the turbo. The function of the exhaust back-pressure valve is to decrease the amount of time the engine takes to get to normal operating temperature. A third part of the system is an EBPV solenoid or regulator which controls the flow of oil to the actuator.
When the engine is cold, the actuator will cause the valve to close, which creates back pressure as if the engine were under load. The back pressure creates a buildup of hot exhaust air within the engine which effectively warms the engine up faster. In cold weather, the actuator is known to force the valve to open and stick open. Additionally, the system commonly leaks oil which requires a rebuild of the entire EBPV system. Due to the commonality of oil leaks and actuator failure, and the expense associated with repairing the two, deleting the EBPV is a common option.
Benefits of 7.3 Powerstroke EBPV Delete
- Increased performance and turbocharger efficiency
- Lower exhaust gas temps
- Repairing a failed EBPV requires the removal of the turbocharger and is expensive
Negatives of an EBPV Delete
- Prolongs engine warm-up time which increases fuel dilution, especially in extremely cold climates
- Increased emissions which will lead to you failing an emissions test
6. Under Valve Cover Harness (UVCH) Failure
Without getting into the technical weeds, the UVCH is a critical component of the 7.3 Powerstroke’s fuel injector system. For the injectors to fire, they need a bit more power than the batteries themselves can provide. Because of this, the engine is equipped with an Injector Driver Module or IDM. The IDM receives the signal or voltage from the ECM to fire the injectors, and then outputs a voltage high enough for the injectors. The UVCH is an electrical connector that transfers the voltage from the IDM to the injectors.
The under-valve cover harness, as it suggests, sits under the valve cover. Given the heat within the valve cover, and the constant shaking of the engine, the connector wires can either melt or rub against the valves and break. The issue is commonly isolated to certain cylinders as one cylinder’s UVCH connection can fail while the others remain intact. There is one wire on each side of the engine, and fortunately, it’s a pretty inexpensive repair.
UVCH Failure Symptoms
- Poor performance and rough engine running (usually limited to 1-2 cylinders)
- Engine misfires
- Usually no check engine light codes
7. (IPR) Injector Pressure Regulator Failure
The IPR, or injector pressure regulator, sits on the high-pressure oil pump (HPOP) and helps control oil pressure. The IPR works in conjunction with the PCM and the injection control pressure sensor (ICP) to regulate and control the amount of pressure the HPOP is building. In turn, this provides oil pressure to the fuel injectors, ensuring the engine gets the accurate amounts of fuel necessary to operate. Rather than a traditional high-pressure fuel pump, the 7.3 Powerstroke’s HEUI injection system uses the HPOP to control the amount of fuel the injectors spray into the engine.
As your 7.3 engine ages, the IPR is known to fail for a multitude of reasons, including the regulator getting stuck, seals failing, sensors going bad, the wires getting damaged, etc. A failed IPR will result in the engine either getting too much or too little fuel which can lead to a multitude of problems.
Failed IPR Symptoms
- Rough idling and poor engine function
- Car stalls at idle
- Engine cranks but won’t start
- Surging acceleration, poor shifting, decreased performance
Because the IPR works in conjunction with the ICP and HPOP, its failure symptoms are virtually identical. IPR’s can be rebuilt for somewhere around $20, whereas a brand new IPR valve is going to run you somewhere near $200 for the part alone.
7.3 Powerstroke Reliability
When you hear the classic “Yeah, my buddy has a diesel with 500k+ miles on it at his ranch”, if it’s not a 5.9 Cummins, it’s a 7.3 Powerstroke. The engine block and internals on these engines were extremely overbuilt and over-engineered for the truck’s power output, making it one of the most reliable and trustworthy diesels ever produced.
The 7.3 Powerstroke has a B50 Life of 350,000 miles, meaning 50% of engines last beyond 350k miles before failing. While I did list a lot of problems above with the 7.3, these problems are primarily minor and inexpensive to fix. Catastrophic engine failure is virtually unheard of, but every engine does have its weak spots. For the 7.3, it tends to be with wiring/electrical-related components like sensors and things of that nature.
Outside of the list mentioned, you should expect some maintenance as these trucks get older and pass the 200k mark. It wouldn’t be uncommon to need to replace the turbocharger (surprisingly easy and cheap), a water pump, maybe the fuel pump, etc., and other components that are high-stress or pressurized.