Troubleshooting 2007 International 4300 Durastar Speed Issue: Turbocharger Actuator #1 Culprit?

Question:

Looking for advice on my 2007 International 4300 Durastar with a DT466 engine. Lately, I've been experiencing a speed issue where I can't go faster than 35-40 MPH on the highway unless it's downhill. Driving around town is no problem. After changing the fuel filter cartridge and installing new batteries, I was able to clear multiple codes relating to Injector cyl, Battery voltage, and Turbocharger Actuator. Despite testing the fuel pressure and finding it within the range of 58 PSI, the issue persists. Could the Turbocharger Actuator #1 be the culprit behind the lack of power going uphill? Any suggestions on what my next steps should be? Your input is greatly appreciated.

Top Replies

Mechanic potential.

Upon starting the vehicle, the actuator arm moves as expected in a sequence, indicating communication between the ECM and the VGT actuator. However, without any DTCs indicating sensor issues, it seems that the actuator feedback may not be reaching the ECM. As someone who mainly works on gasoline vehicles, troubleshooting diesel vehicles can be a challenge. Could the turbine be causing resistance, leading to the actuator DTC? If the issue persists, the truck will be taken to a shop for further diagnosis. While sensors like the EBP sensor have not been ruled out as potential causes, it is puzzling that there are no sensor-related DTCs. Unsure of whether the actuator needs to be replaced, I am hesitant to spend $400 without certainty. Any insights or advice would be greatly appreciated. Thank you for your assistance!

Could you please provide the last eight digits of the VIN number? It appears that there may be a fuel issue, as 58 psi is considered low and could potentially decrease further while driving under a heavy load. (Note: When I removed the fuel pressure regulator, approximately 3-5 tablespoons of a substance resembling black motor oil dripped out, which seemed unusual.) Which specific fuel pressure regulator are you referring to in this case? When you replaced the filter, did you notice any buildup of dirt and debris at the bottom of the housing? The fuel pressure regulator is situated at the bottom of the filter housing and consists of a stainless orifice with a small spring-loaded plunger. To clean it, remove the regulator and blow it out using compressed air, using a 7mm allen socket for removal. Unlike other models, the 2007 DT466 does not feature a fuel return line. Instead, the fuel flows back from the regulator to the fuel inlet on the filter housing. Any impurities in the filter housing circulate through the regulator at the bottom of the housing, reenter the inlet, pass through the transfer pump, and circulate back into the housing, potentially leading to a decrease in fuel pressure. To prevent any contaminants from entering the engine, be cautious when cleaning the housing, particularly around the tube in the center of the fuel filter housing where the filtered fuel enters the engine. If there is a significant buildup of debris at the bottom of the filter housing after removing the fuel pressure regulator, disconnect the fuel supply line from the housing and clean and flush it to remove any debris. If necessary, you can remove the housing for a more thorough clean, ensuring you have the oval O-ring to reseal the housing to the intake manifold. The strainer at the bottom of the housing may become clogged over time and likely requires cleaning. For a more accurate assessment of fuel pressure under load, consider installing a gauge at the quick coupler on the plastic filter cap of the 2007 model. While issues with the turbo actuator may not directly cause the power loss you are experiencing, it is worth checking for any potential boost leaks.

The fuel filter housing showed no signs of contamination. Upon inspecting the fuel filter canister, I found no regulator but did clean the strainer. Unfortunately, I do not have the VIN as the truck is currently at the shop. I cleaned the IPR valve, which seemed to improve performance briefly before the issues reoccurred. The shop replaced the barrel sensor and MAP sensor, allowing the truck to reach full speed on the freeway for a temporary period. However, the problem has resurfaced, prompting concerns about oil or soot entering the intake and affecting the MAP sensor readings. This may be causing the VGT to overboost, as indicated by the mechanic's diagnostic report. The mechanic plans to clean the MAP sensor and inspect the intake for any debris. Your feedback is greatly appreciated. Thank you for your input!

I would recommend checking the fuel pressure while driving at high speeds to ensure optimal performance and efficiency. This will help you identify any potential issues that may be affecting your vehicle's performance on the highway.

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Frequently Asked Questions (FAQ)

FAQ: 1. What could be causing my 2007 International 4300 Durastar with a DT466 engine to have a speed issue where it can't go faster than 35-40 MPH on the highway?

Answer: Answer: Several factors could be causing this issue, such as a faulty Turbocharger Actuator, injector problems, low battery voltage, or fuel pressure issues.

FAQ: 2. How can I troubleshoot a speed issue in my International 4300 Durastar despite changing the fuel filter cartridge and installing new batteries?

Answer: Answer: In addition to checking the fuel pressure and clearing error codes, further diagnostics may be needed to pinpoint the exact cause of the speed issue, possibly including testing the Turbocharger Actuator.

FAQ: 3. Could the Turbocharger Actuator 1 be responsible for the lack of power going uphill in my 2007 International 4300 Durastar with a DT466 engine?

Answer: Answer: The Turbocharger Actuator 1 could indeed be a potential culprit behind the lack of power going uphill, as issues with the turbocharger can significantly impact the engine's performance in various driving conditions.

FAQ: 4. What are some recommended next steps to address the speed issue in my International 4300 Durastar?

Answer: Answer: Consider consulting a qualified mechanic or technician to perform a thorough diagnosis, including specific testing related to the Turbocharger Actuator 1 and other relevant components to determine the root cause of the speed issue.

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