The 6.0L Powerstroke was mostly a failure, except for a few positives, including the variable geometry turbocharger (VGT). The VGT is effective at high and low speeds thanks to a clever vane system regulating exhaust gasses in the turbo.
Unfortunately, as with many parts on the 6.0L Powerstroke, the VGT has its gremlins.
The symptoms of a failing VGT solenoid on a 6.0L Powerstroke include increased turbo lag, inconsistent turbo performance, and VGT sticking. Coil resistance above 4.18 Ohms between the solenoid terminals also points to a failing solenoid.
This piece looks deeper into the symptoms of a failing VGT solenoid.
1. Increased Turbo Lag
In some turbocharged cars, it takes a while before pressure from the exhaust gasses activates the turbo – a phenomenon dubbed turbo lag. A small turbo eliminates turbo lag as it doesn’t need much exhaust pressure to spool up.
However, a small turbo is ineffective at high speeds as it can’t handle high exhaust pressures. A big turbo suffers from turbo lag, but it performs exceptionally well once exhaust pressure builds up with the revs.
The VGT is a hybrid of a small turbo and a large one. At low RPMs, the vanes partially close, pressuring the exhaust gasses driving the turbine blades.
Conversely, at high RPMs, the vanes open, allowing the already pressurized exhaust gasses to spin the turbine. Thanks to the vanes, the turbo delivers optimum performance throughout.
The VGT solenoid controls the system that opens and closes the valves. When the solenoid fails, the VGT’s valves remain open, turning the turbo into a ‘big’ turbo. Therefore, the turbo won’t work as effectively at low speeds as it would when the valves are partially closed.
Consequently, you’ll notice increased turbo lag – the power delivery at low speeds reduces and improves as the turbo pools. The VGT was designed to beat turbo lag without affecting high RPM performance.
Therefore, when you notice poor turbo output at low speeds and standard power delivery at high speeds, the VGT solenoid is likely the culprit.
2. Inconsistent Turbo Performance
The VGT is an intelligent device that ensures optimum turbo performance at different speeds. Therefore, whether you are lining up for a drag race, cruising on the interstate, or winding up and down mountain roads, the turbo delivers the power you require.
Engineers designed the VGT to work consistently at all speeds through the valve system. Therefore, the VGT provides linear performance throughout an extended rev range.
If you start noticing power drops at different revs, it shows that the VGT has lost its consistency. The valves ensure the VGT performs well throughout, so inconsistent power delivery indicates that the valves aren’t opening and closing as they should.
The solenoid controls valve movement; therefore, malfunctioning valves on a 6.0L Powerstroke can point to an ailing solenoid. The issue will likely worsen as time passes, so it’s crucial to replace the solenoid ASAP.
3. Increased Coil Resistance
The VGT solenoid converts electrical energy into movement, adjusting the valves depending on your throttle inputs.
Increased coil resistance affects the effectiveness of the solenoid, impacting the performance of the VGT: the all-important vanes won’t move as designed.
The solenoid is easy to get to as it protrudes from the turbocharger’s housing.
Follow this solenoid-removal procedure:
- Locate the solenoid; it’s held in place by a bracket secured by one bolt.
- Unscrew the bolt using an 8-mm (0.3-in) socket and remove the bracket.
- Twist the solenoid to remove it, but don’t rock it against the housing.
- Use a clean rug to catch the solenoid as it comes out covered in motor oil.
It might seem unremarkable to you, but that piece of equipment runs that all-important turbo. Increased resistance prevents it from moving the actuator effectively. You’ll need a multimeter to measure the coil’s resistance.
Follow this process to ascertain a VGT solenoid’s resistance:
- Turn the digital multimeter to ohms, the unit of resistance.
- Place the multimeter probes on the pins.
- Note the reading.
The resistance of a functioning solenoid should be between 3.42 and 4.18 Ohms. A reading above 4.18 Ohms indicates that you have a faulty solenoid that needs immediate replacement.
4. VGT Sticking
VGT sticking is a common problem in 6.0L Powerstroke engines, especially in vehicles clocking over 100,000 miles (160,934.4 km). Sticking happens when the vanes stall in one position.
Vane sticking is sometimes caused by the buildup of soot or corrosion in the turbo housing, explaining why most drivers rush to clean the turbo after identifying sticking symptoms.
Sticking symptoms vary depending on the vane position. If the vanes are nearly closed, you’ll notice no change in performance at low speeds and poor power delivery at high speeds.
Conversely, if the vanes are stuck open, you’ll experience deficient low-end performance and satisfactory power output at high speeds, i.e., turbo lag.
Before you rush to remove and disassemble your turbo for cleaning, consider checking the solenoid’s performance. It might be the cause of the sticking, especially if the turbo is relatively new.
The solenoid controls the movement of the vanes. Therefore, the vanes will remain in one position when it stops working – they’ll ‘stick’.
5. Code P0046 on a Diagnostic Tool
If the check engine light on your car comes on or you suspect solenoid malfunction, connect your vehicle to a diagnostic scanner.
If it produces a code POO46, your 6.0L Powerstroke has a solenoid issue. [This piece lists ICP sensor fault codes and other symptoms of a failing ICP sensor on a 6.0 Powerstroke.]
The POO46 might indicate that the VGT solenoid:
- has a damaged connector
- has failed
- has a compromised control circuit
Electronic issues can be resolved without replacing the solenoid, but damage or failure will force you to replace the solenoid.
6. Stationary Solenoid Valve
The solenoid valve inside the coil moves to control the VGT vanes. If it remains stationary during a test, it shows that you have a broken VGT solenoid.
Test valve movement as follows:
- Remove the solenoid as directed above.
- Apply ground and power to the solenoid.
- Check for movement of the button at the end of the solenoid.
The button should cycle in and out; if it doesn’t, your VGT solenoid is broken.
How To Replace a Faulty VGT Solenoid on a 6.0L Powerstroke
There’s little you can do to prevent VGT solenoid malfunction beyond regular car maintenance. It’s one of the many parts of a 6.0L Powerstroke that inevitably fail.
A damaged VGT solenoid can’t be salvaged – the only solution is replacement. The VGT solenoid is a crucial component of the VGT, so I advise against driving with a malfunctioning solenoid.
VGT solenoid replacement is a simple job as it’s one of the more accessible parts of a 6.0L Powerstroke.
Follow this detailed process to replace a faulty VGT solenoid on a 6.0L Powerstroke:
- Disconnect the battery.
- Locate the turbo at the center of the engine bay near the windshield.
- Raise or remove the covering on top of the turbo to free up working space.
- Locate the solenoid – it protrudes from the center of the turbo housing – and remove the electrical connector.
- Use an 8-mm (0.3-in) socket to unscrew the bolt holding the solenoid’s bracket.
- Pull the solenoid outwards to remove it. You might need to twist it gently to break the seals of the o-rings.
- Use a clean rug to collect the VGT as it comes out covered in oil.
- Soak the o-rings and valve of the replacement solenoid in oil for several minutes.
- Don’t reuse the old bracket and retaining bolt, as new VGT solenoids come with new hardware.
- Install the solenoid. The springy solenoid tends to push back until you reattach the bracket, so don’t be alarmed by the solenoid’s movement.
- Install the bracket and coat the retaining bolt with anti-seize to facilitate future removal. Torque the bolt to 18 lb-ft (26.79 kg-m).
- Clean the electrical connector and reinstall it.
With that, you can forget solenoid problems for, hopefully, the next 100,000 miles (160,934.4 km). VGT solenoid problems are relatively rare compared to other VGT ailments.
An Aftermarket Solenoid Will Serve You Better for Longer
While on the topic of replacing solenoids, I’d like to point out that the stock VGT solenoid isn’t the best option for the VGT on a 6.0L Powerstroke.
A new one will serve you well for a while, but it’ll inevitably lose performance and break down – durability isn’t a 6.0L Powerstroke’s strong point. You can avoid dealing with the stock solenoid’s problems by getting an aftermarket VGT solenoid.
Aftermarket solenoids improve the turbo’s performance, delivering boost sooner. The VGT is designed to provide power as soon as you apply the accelerator; an aftermarket solenoid expedites power delivery from the turbo, enhancing an already impressive tool.
Therefore, if you’ve upped the performance of your 6.0L, purchasing a custom solenoid is a no-brainer: it’ll handle the amplified power demands better than the OEM part. Aftermarket solenoids deliver a higher peak boost while reducing harmful exhaust emissions.
It all sounds merry until you look at the price tag: aftermarket solenoids, like the Lightning Bolt Performance solenoid, can be more than five times more expensive than OEM solenoids. However, the benefits and the longevity they offer justify the price difference.