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Troubleshooting P0172 on the Ford F150 GuideMechanic.Com When your Ford F150’s check engine light starts to blink, it might be time to start looking at your car’s trouble codes.
The P0172 code can mean many things depending on how your vehicle is set up. Your car might be displaying several symptoms, such as high pressure in the fuel rail or system, idle problems, black smoke coming from the exhaust, or other problems that may require the assistance of a mechanic.
Troubleshooting P0172 on the Ford F150
Fuel rail/system pressure – Too high
If you are experiencing cranking, stalling, or other vehicle problems, the first step you need to take is to check your fuel pressure. Fuel pressure readings are taken with a special device called a fuel pressure tester.
This device has a green or black port cap, and you must replace it after reading the data. Normal fuel pressure for a Ford truck engine is 50 to 60 PSI, so if the gauge does not indicate a high level of fuel pressure, it may be time to replace the pump.
Low fuel rail pressure is a common problem on Duramax trucks. The degree of low fuel pressure varies between vehicles, but it can leave you stranded.
Fortunately, there are tuning platforms available online that allow you to watch the problem in real time, and even record the results for transmission technicians to analyze.
These platforms offer detailed information about the engine PIDs and allow you to pinpoint the underlying cause of this problem.
When fuel pressure is too low, the car will misfire randomly. This is a common problem with returnless fuel systems, as the return line is eliminated.
The air/fuel mixture may be off, resulting in poor performance and fuel mileage. Fortunately, the Ford PCM updates its regeneration strategy and calibration software every few months to help you avoid the problem before it gets worse. And the best part is, the diagnosis is easy and inexpensive!
You can diagnose this problem by checking your fuel pressure with a manual tester, which can be used to measure the fuel pressure at the fuel rail and the reading from the sensor.
A more sophisticated scan tool can monitor your vehicle’s fuel pressure data and determine the source of the problem.
However, fuel pressure is a critical part of troubleshooting the fuel injector system. In some cases, too high fuel pressure is caused by a restriction in the return line, but this is not the only cause. Make sure you have the vehicle serviced by a trained professional.
Fuel return line pinched
If you’ve recently noticed that your Ford F150’s fuel return line is pinched, you need to replace it. You can do so by replacing the fuel supply line, as well as the return line.
If the line is already blocked, you can try blocking it with a 5/16″ plug, which you can make by using silicone shot into a tube. You can also angle the line by attaching a 2″ tube to the return line.
Performing a fuel pressure test is relatively simple. All you need is to pinch the return line, and measure the pressure in the hose at both idle and load.
Then, you can increase the pressure in the return hose so that the system regulator is functioning properly. If you can do this test without pinching the line, it’s safe to assume that the fuel return hose is not blocked. If the pressure is still low, you can adjust the regulator.
If the pressure is too high or too low, then it’s time to get a professional technician to replace the fuel return line. Fuel hoses are an important part of the engine and if they get damaged, they can affect the engine’s performance and safety.
Check the return hose every time you take your truck in for service. There are a few signs that your fuel return line is pinched, including a squeaky noise and a smell of gasoline.
To determine whether you’re dealing with a faulty fuel pump pressure regulator or in-tank fuel pump, test the pressure of the return line.
It should hold the pressure for several minutes after shutting off the engine. If the pressure goes away too quickly, there’s a problem with the fuel pump, such as a bad pressure regulator or defective in-tank fuel pump. When you’re done with this test, you’ll know whether or not you need to replace the fuel pump.
Troubleshooting P0172 on the Ford F150
Idle erratically
Your Ford F150 may be idle erratically for a variety of reasons. One of the most common causes is a dirty air filter. If this is the case, it is worth having your vehicle looked at by a mechanic.
The good news is that there are several simple fixes for this issue. Here’s how to check your OBDII codes for any issues. Then, follow up with the manufacturer’s recommendations.
Check your air filter. If it’s been a while since you changed it, or you’ve recently driven your F150 in tough conditions, it’s possible that your air filter has become clogged.
This can lead to poor idle conditions. It’s inexpensive and easy to replace. Also, check your oxygen sensors. These monitor exhaust and help your ECU determine the right air/fuel mixture.
Clean the throttle body. It can be clogged with dirt or debris. If you suspect that the idle air control is dirty, use carb cleaner to clean it. You can also clean the throttle body with a carburetor cleaner.
These simple steps should help stabilize the idle of your Ford F150. If none of the above suggestions work, try replacing the air filter. Then, run the car for a short drive to see if it improves.
Black smog coming out of exhaust
A Ford F150 owner brought in his car for a rough idle and lack of power. He noticed black smog coming from the exhaust and smelled fuel.
During the inspection, he found no malfunction indicator light on the dashboard and no diagnostic trouble codes in any module.
He replaced the fuel rail pressure sensor, fuel pump, and the powertrain control module. Despite the recurring problem, the technician was surprised to find no other symptoms.
If you notice black smog coming out of your Ford F150, it’s time to take it to the mechanic immediately. The exhaust smoke is a symptom of excessive fuel burning.
Diesel engines usually emit black exhaust smoke. In contrast, thin white smoke is probably condensation and is not a concern.
Nevertheless, if the smog persists for a long time or is quite thick, it could be a sign that the engine head gasket or engine block is in danger.
A dirty filter is another cause of black smoke coming from your car’s exhaust. When your vehicle’s filter is dirty, it is restricting the amount of clean air reaching the engine.
This will result in less efficient running. The engine will have a poor idle and be less responsive. It will also have trouble starting, and gas mileage will be affected. You can also visit a mechanic for more information.
Dirty air filters can prevent complete combustion of the fuel charge. This can increase the PM by forty to fifty percent. Dirty air filters can also cause excessive oil consumption.
When oil consumption is high, it means that the engine is not receiving enough oil. This can increase the amount of black smoke produced by the vehicle by 85%. If this happens frequently, you should consider a repair or replacement of the air filter.
Troubleshooting P0172 on the Ford F150
Cost to diagnose
The first step in troubleshooting a P0172 error code is to check your vehicle’s fuel trim. If the trim is too long, it means that you’ve got a short fuel trim location.
If you see this, disconnect the battery cable from the engine. This will clear the adaptive (fuel trim) memory. When Closed Loop Fuel Control is indicated, the short trim should remain near zero.
The code may be due to various issues. For instance, a dirty mass airflow sensor can overstate the amount of air entering the combustion chamber and cause an overly rich condition.
Additionally, the sensor can point to a faulty or bad O2 sensor or injectors. A worn spark plug may also cause a rich running condition.
If your vehicle is constantly exhibiting the symptoms of a P0172 error code, it may be time to have your car checked by a mechanic.
Another reason why a P0172 code is displayed on your dashboard is a lack of air in the engine. The fuel-air ratio is too rich or too lean.
If you’re driving a Flex Fuel vehicle, you’ll have to check the alcohol content of your gas before using it. Other diagnostics that will determine if the problem is caused by the fuel-air ratio are the air filter and MAF. In some cases, the problem can be a vacuum leak.
If you’ve noticed slow acceleration or sluggish acceleration, you need to check the torque converter and replace it. Another common problem is a bad mass airflow sensor, which requires a torque converter and other components to function properly.
The cost of diagnosing a Ford F150 p0172 error code is approximately $150. You can also try replacing the fuel filter and the mass airflow sensor.
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