If you have a car or truck and think it may have low fuel pressure, several symptoms are caused by fuel delivery issues.
Symptoms include long start times, rough idle, check engine light on, misfire codes (P0300-P0308), engine running lean (P0171 Code), and reduced engine power.
Low fuel pressure is often described as the vehicle running out of gas.
Symptoms of Low Fuel Pressure
- Long Engine Start Times
- Engine Does Not Start
- Rough Idle
- Check Engine Light On
- Misfire (P0300-P0308) Codes
- Engine Running Lean (P0171 Code)
- Reduced Engine Power
If you have to wait longer than normal for the engine to start, it may be not getting enough gas.
A fuel pressure gauge can be used to see if the engine is getting the correct amount of pressure to start.
The engine may have a rough idle since the fuel delivery is sporadic and not at a steady rate.
The engine error codes can be read with an OBDII scan tool.
There are many low-cost scan tools available, and many automotive stores will do scans for free.
If one of these is off, such as no gas, then a misfire will occur.
When the vehicle computer is scanned for error codes, a P0300-P0308 misfire error code will often be given.
A lean condition points to a fuel delivery problem, such as low fuel pressure.
When scanned for errors, lean condition codes will be given, such as a P0171 Code.
When pressing on the gas pedal, the vehicle may be slow to start and have no power.
Possible Causes of Low Fuel Pressure
- Faulty Fuel Pump
- Clogged Fuel Filter
- Bad Fuel Pressure Regulator
- Bad Fuel Rail Pressure Sensor
- Fuel Tank Contaminated
- Fuel Line leak or Clogged
The fuel pressure can be tested with a pressure gauge to see if it is working correctly.
A clogged fuel filter is common with vehicles that have an inline filter.
Not all vehicles have an inline filter with many located with the fuel pump located in the gas tank.
If your vehicle does have an inline fuel filter it is a good idea to replace it since it is a part of regular maintenance and a common failure.
The fuel pressure regulator can cause issues if it becomes clogged up.
It is usually located on top of the engine but can also be located on the fuel pump, mainly with Chrysler or Dodge vehicles.
Usually, when a fuel rail pressure sensor goes bad, it will give another code, such as
Often, contaminants will block the fuel filter and sometimes the fuel pump strainer.
If a fuel line has been damaged, it may be leaking fuel.
A clogged line will also cause issues and block gas.
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