Symptoms and Causes of Low Fuel Pressure

Low fuel pressure can be a common problem in all types of vehicles. Generally speaking, low fuel pressure means you don't have enough fuel getting to the engine, and/or you have too much air coming in. The fuel-to-air intake ratio is thrown off and it will cause engine performance issues. You may have trouble getting the car started at all when the fuel pressure is too low.

Symptoms of Low Fuel Pressure

Here are a few signs that you may have low fuel pressure:

  • Engine Won't Start—It is cranking, but isn't starting up.
  • Check Engine Light—An illuminated check engine light could mean a fuel system problem.
  • Black Smoke—Dark smoke coming from the tailpipe often means the vehicle is burning too much fuel, which could be a fuel system, engine or exhaust system issue.
  • Backfiring Engine—If the engine pops and backfires a lot while running, it's usually because it is getting too little fuel or too much air.
  • General Engine Issues—Stalling, inconsistent running and the issues noted above can all be signs of low fuel pressure.

Causes of Low Fuel Pressure

The first step is identifying you have a fuel pressure problem. A good mechanic can inspect your engine, fuel system and exhaust/emissions system to determine the source of the low fuel pressure. Here are some of the most common culprits:

Failing Fuel Pump

The fuel pump regulates the amount of fuel distributed to your engine when you press the gas pedal. It can malfunction or lose performance consistently over time, so it may be the cause of your low fuel pressure.

Clogged Fuel Filter

The fuel filter plays an important role in making sure clean fuel gets to your engine by filtering out any dirt, debris or other contaminants that can build up in the gas tank and fuel lines. Eventually, the filter will wear out or it can become clogged, which will cause fuel system and engine performance issues.

Damaged Fuel Line

There could be some sort of damage in the fuel lines. A loose connection, clogged line, leak or kink could lead to reduced fuel pressure.

Engine Problems

Low fuel pressure and the symptoms described above may not be a result of a fuel system problem. There could be a problem within the engine itself. 

Air Intake Problem

Whether you have an older carburetor system or modern fuel injection system, your engine needs the right mixture of air and fuel to combust properly. An air intake problem could lead to too much air getting in, or dirty air causing the fuel to burn poorly. There could be some sort of damage, or it may be something as simple as a dirty engine air filter that needs to be replaced.

Exhaust System Issues

Problems with your exhaust and emissions system will also lead to poor engine performance. A symptom that might seem like a fuel system issue could actually be traced back to the catalytic converter, oxygen sensor or something else in the exhaust system.

These are just some of the symptoms and causes of low fuel pressure and general engine performance concerns. If you are experiencing any issues with your vehicle in Northern Delaware, call Fox Run Auto at (302) 597-9205 or schedule a service appointment online. Let our technicians determine the problem and provide the correct automotive solution.


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