Is it the Fuel Level Sender or Just the Wiring?

Fuel pumps are powered by electricity and are connected to a vehicle’s electrical system. Like batteries -- and alternators for that matter -- fuel pumps have both a positive and negative terminal. Read More

Sensors That Affect Fuel Delivery: Part 2

In part 1, the article discussed sensors that use information forwarded to the PCM/ECM by other sensors to make adjustments to the air-to-fuel ratio the engine requires to run efficiently. Part 2 discusses the sensors that feed the information to the computer. Read More

Sensors That Affect Fuel Delivery: Part 1

If you have a problem with the fuel delivery system, it may not always be the fuel pump, relay or filter, though those are the first things that people think of when fuel is not making its way to the engine. Read More

Installing a Re-Pop Tank in Your Classic Car

Whether you're completely rebuilding that classic beauty or just tuning its engine, you'll probably have to replace that decades-old fuel tank. There's no way to know how much debris, rust or old rags are in there...Read More

Mass Airflow Sensor: Big Problems from a Little Instrument with an Easy Fix

The mass airflow (MAF) sensor measures the volume of air entering the engine so the Engine Control Unit (ECU) can calculate how much gasoline is needed to deliver the proper fuel-air ratio. Sometimes, however, a malfunction in this little instrument can lead to big problems... Read More

Inspection and Testing Fuel Injectors

There are three styles of original equipment (OEM) fuel injectors. In each case they are high impedance-10 to 17-ohm injectors and referred to as Saturated Circuit drivers and injectors. Read More

Ignition System Checks

If your car is not starting, it could be due to a number of reasons, one of which could be an ignition system problem. In order to diagnose problems in the ignition system, it’s important to break it down into the following parts: Read More

The EGR System and How it Affects the Fuel Delivery System

The fuel delivery system relies on variables about the engine. The sensors supply these variables to the engine’s computer, and the computer calculates the amount of air and fuel needed for optimal combustion – usually a 14.5:1 air-to-fuel mixture. Read More

ICM - What It Is and the Importance of a Good One

An ignition control module is the brain behind the starting of your car. An ICM is a computer chip with ''fast start circuitry'' that serves two functions. The first thing it does is receive information sent from the crankshaft position sensor. With that information, the ICM tells the coil pack when to fire. Read More

Mass Airflow Sensor: An Easy Fix for Big Problems from a Little Instrument

As we’ve discussed in a previous post, the mass airflow (MAF) sensor measures the volume of air entering the engine so the Engine Control Unit (ECU) can calculate how much gasoline the fuel injectors should deliver to each cylinder in order to create the proper fuel-air ratio. Read More

How To Replace Fuel Injectors

Multiport fuel injection is the predominant type of fuel injection used in today’s vehicles. There is a fuel injector for every cylinder. Read More

Fuel Pump Operation and Failure Signals

Older vehicles relied on a carburetor to supply fuel for combustion. Carburetors needed adjustments routinely to keep parts moving fluidly for engaging and disengaging the choke. Read More

How to Pinpoint a Bad Fuel Injector

Fuel injection is a much more efficient method of introducing fuel into the cylinders of an engine versus carburetors. Carburetors, being centrally located on the intake manifold, supply more fuel to the closest cylinders than to those farthest away. Read More

Electronic Control Unit: Can't Drive Without It!

Most people know that modern automobiles use an electronic fuel injection system, but how does it know how much fuel or air to deliver and when? Read More

How OBD-II Monitors The Fuel Delivery System

Although OBD-II was designed mainly to detect emission faults, it has evolved to monitor many other processes as well, ranging from fuel trim to the evaporative system to the coolant thermostat. When OBD-II detects the same problem occurring in two separate drive cycles, it illuminates the "check engine" light to alert the driver and encourage a prompt fix. Read More

Ground Connections – Minor Problem, Simple Solution

If you are performing a voltage drop test and you find that the ground side shows a high resistance or high voltage drop, one of the first places to check is the ground location on the vehicle. Read More

Fuel System Tips and Tricks

 When the fuel pump or another part of the fuel system malfunctions, your vehicle could leave you in a bind. You may not be able to ensure perfect performance at all times from your fuel system, but you can do some things that extend its useful life. Read More

Are Computers Taking Over the Auto Industry?

The role of an automotive technician is becoming more computerized by the day. From fuel pump pressure to engine performance, nearly everything in a vehicle now runs through a centralized computer system. Computer interfaces are also increasingly being used to control vehicles and to run regular system maintenance checks. Vehicles today can self-stabilize, self-park, and even self-drive. Read More

Fuel System Precautions

Fuel System PrecautionsLiquid fuel poses several types of hazards such as poisonousness, corrosiveness and flammability. Gasoline is the most dangerous of these fuels, although these precautions also apply to diesel fuel. Fuel safety precautions are generally standard for all vehicles, and may be categorized into electrical, exposure, leaking and storage precautions. Fire prevention is also an important consideration when we perform maintenance on a fuel system. Read More

What's the Best Air/Fuel Ratio to Use?

 In an ideal world, a scientifically perfect air/fuel ratio for a gasoline engine with an electric fuel pump is 14.6:1; the mix should contain 14.6 parts air for each 1 part of fuel. However, in the real world, things don't work perfectly. Read More

Importance of Proper Fuel Pressure on a Fuel Injected Engine

Importance of Proper Fuel PressureFuel pressure and volume are vitally important for efficient engine operation on fuel injected engines. If an engine is running rough, has an irregular idle, and a lack of power on acceleration, don’t dismiss the fuel system as a possible cause. Many times in which such a scenario is present, the fuel system isn’t suspect since it’s getting fuel pressure and running. Read More

The Oxygen Sensor and How It Affects the Fuel System

When auto manufacturers started using oxygen sensors to determine how much oxygen was in the exhaust, they used only one. Now, most vehicles use at least two oxygen sensors and many use four. In many cases, the oxygen sensors have preheaters as they do not work properly when they are cold. Read More

Fuel Leak Checks

Fuel Leak ChecksA faulty fuel injector is one of the more common fuel injection system problems and can seriously affectan engine’s performance. A fuel injector can leak internally into the cylinder or externally through one of its sealing o-rings. A leaky fuel injector also wastes gas and significantly reduces gas mileage. In extreme cases, an excessive amount of fuel can leak onto a hot engine, ignite and cause an engine fire. Read More

Decoding the Most Commonly Encountered Trouble Codes

Decoding Trouble CodesIf your "Check Engine Light" is on, then a fault somewhere must have triggered a trouble code in your engine's computer. You can't tell whether the problem is in the fuel pump, EGR or elsewhere without using a scan tool, but we can look at the most common areas of trouble. Read More

Fuel Filter Inspection

Fuel Filter InspectionFuel filters can be classified into in-line fuel filters and tank filters. An in-line fuel filter is typically used on vehicles with fuel injectors. The filter has an inlet connection on one end and an outlet connection on the other end. The filter connects in-line with the fuel feed pipe so that the fuel flows through the filter. Some fuel filters also have a vapor return outlet on the outlet side of the filter that carries vapor back to the fuel tank, which prevents vapor lock. Read More

Five Things Everyone In The Automotive Industry Should Know About Fuel Injectors

Fuel InjectorsTo the layperson fuel injectors are far from sexy, or likely even interesting for that matter. To those in the automotive industry, however, fuel injectors are as glamorous as a car part gets. With that said, not everyone is a genius and automatically knows everything there is to know about the fuel injector. For such reason, here are five things everyone in the auto industry should know about fuel injectors.
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Common Problems With Fuel Gauge Working

To check the amount of fuel left in the gas tank we generally look into the fuel gauge mounted on the vehicle’s dashboard. The needle on the gauge moves from F to E as we use the gasoline. But we have to understand that many times it doesn’t show the exact fuel level of the tank because it is controlled by a sensor or Sending Unit present in the gas tank. Sometimes, the needle of the gauge stays on full and doesn’t move for a while though the vehicle puts up few miles after filling the gas. Read More

How do Oxygen Sensors Work With Your Fuel Delivery System?

Oxygen SensorsOxygen sensors are designed to work with your vehicle’s fuel delivery system to ensure optimal performance and fuel efficiency. These devices, also referred to as O2 sensors, monitor the emissions or exhaust gas to regulate the air to fuel mixture delivered to the engine. Read More

Engine Sensors and How They Influence Fuel Flow

The functions of today’s fuel injected engines rely completely on a powertrain control module (PCM) and its associated sensors, of which there are many. Fuel has the ability to adapt to altitude, temperature, humidity, and load while maintaining a constant fuel ratio of 14.7:1. Read More

EGR Valves: Making Cars "Greener" for Decades

 It turns out that electric vehicles aren't the only "green" cars on the road. Ordinary gas-fueled engines, whether three months old or 30 years old, use an EGR valve to prevent the formation of toxic nitrogen oxide compounds (NOX) that pollute the atmosphere. This simple valve works magnificently while lowering your engine's octane requirements, which reduces the risk of detonation, or spark knock. Let's look at the basics of EGR valve operation. Read More

Can Your Fuel Pump Provide Too Much Pressure?

 The fuel pump in your vehicle draws gas from the tank to supply the fuel to the carburetor or fuel injectors. A specific amount of pressure is needed to ensure the fuel is delivered correctly, and in the right amount. Replacing a fuel pump with the incorrect model can lead to excessive pressure and engine operating problems. Read More

DIY: How to Calculate Fuel Pump and Injector Size

 If you enjoy building your own custom engine designs or customizing existing engines, you know you have to take more than just pistons and valves into consideration. The best engine design will never run correctly without... Read More

The Wrong Way and Right Way to Empty a Gas Tank

There are at least three reasons you may need to empty a gas tank:

  1. Someone put the wrong fuel in.
  2. You need to drop the tank.
  3. You need to replace the fuel pump or sender unit.

Internet forums are full of advice on how to perform this task, but much is of questionable quality, so here are a few do’s and don’ts. Read More

How to Boost Your Engine's Power without Breaking the Laws of Physics: Part 2

If you're looking for ways to squeeze more power out of your car's engine without getting into things like supercharging or breaking the laws of physics, here are a few hints to get you started! Check out Part 1 of this series for more ideas. Read More

Description of the Throttle Position Sensor and Testing Procedures

The throttle position sensor (TPS) is a potentiometer located on the throttle body and attached to the throttle plate opposite the throttle linkage. It has three wires: battery voltage, 5-volt reference, and a signal wire. Its purpose is to signal to the powertrain control module (PCM) the amount and speed of the throttle opening. This is an indication as to the demand placed on the engine at any given time. Read More

Decoding Engine Trouble Codes - Part 1

If you're a fan of the show "Big Bang Theory," you know that Penny's "Check Engine Light" is always on – to Sheldon's consternation. He thinks it means the end of the world while she dismisses it as a minor annoyance, but who's right? Read More

Fuel Filter Basics- How It Works, Why It's Important and How to Replace It

 A clean fuel filter is crucial to keeping a fuel delivery system in proper working order. By filtering out impurities from fuel, the filter prevents fuel injectors from becoming clogged and helps maintain a vehicle's peak performance level. Read More

Checking Fuel Pressure Regulator

How do I know if the fuel pressure regulator is stuck open or leaking or if it is stuck closed? Engine with hard-start condition could be the result of a faulty fuel pressure regulator and not the fuel pump itself. Check for these signs while performing fuel pressure tests. Read More

Troubleshooting EGR Problems

Your vehicle's Exhaust Gas Recirculation (EGR) system reduces harmful NOx emissions that exacerbate air pollution. If your EGR system becomes inoperative or just leaky, it could create problems with drivability, such as a rough idle, detonation, hard starting, stalling, and increased NOx or hydrocarbon emissions in your exhaust. Since some of these symptoms could mimic problems with the fuel delivery system, it's important to rule that out as a potential cause before focusing on the EGR. Read More

All About The Fuel Pressure Regulator- Does It Need To Be Replaced?

Those of us that have at least a fundamental knowledge of automotive repair also know just how vital the fuel pressure regulator can be to the working order of a car. Despite the thought by some novice mechanics that it is overly complicated, the fuel delivery system is actually relatively simple. You pump the gas into the car, and then it is stored in the fuel tank before it makes its way to the engine. However, between being stored in the fuel tank and being transferred to the engine, the gas must first go through the fuel pressure regulator. Read More


Beginner's Guide to Tools and Instruments

Tim Allen once said, ''I have a thing for tools.'' More than likely, he has a different tool for every job. If you are someone that does mechanic work out of necessity, and not because you have a passion for the work, sometimes it's hard to know exactly which tools are necessary and which ones you can do without.

While those of us that enjoy working on vehicles usually try to accumulate as many tools as possible, there are ten no one should be without: Read More

Fuel Pump Failure - Knowing the Nightmare, But Not the Cause

A problem with your vehicle's fuel system is one of the most frustrating automotive issue experiences you can have. Unlike a dead battery, a flat tire or an overheating engine, sometimes problems with the fuel system aren't definitive. While sometimes the vehicle won't start at all when you have problems with the fuel system, other times the motor still runs and you can drive the vehicle. However, in this situation, the vehicle won't run to its full potential and it will sputter, putter, and lurch its way down the road. Read More

Avoid These 5 Fuel System Diagnostic Errors

 As auto manufacturers keep striving to improve car engines and their fuel burning efficiency, fuel systems incars keep getting more and more complex. A phenomenon that's arisen as a result of these innovations is that fuel delivery issues are being misdiagnosed. In some cases, technicians have been returning brand new fuel pumps thinking they are defective, when in fact the actual cause of the issue was a defective fuel pump relay or crankshaft sensor. Read More

6 Factors That Affect The Fuel Pressure In Fuel Pumps

To have proper delivery of fuel at correct flow rates and pressure from gas tank to fuel injectors it is essential to maintain steady gasoline supply in the fuel lines. Proper fuel delivery is essential for maintaining good engine performance.Read More

Finding the Correct Fuel Pump for Specific Applications

It is important the correct fuel pump replacement is sold and installed in the specific applications. There are several factors that are important considerations in looking up the application-specific fuel pump. Also, GM uses several different in-tank sender assemblies for the same make and model of vehicles. Read More

Choosing Between Mechanical Fuel Pump And Electric Fuel Pump

The purpose of fuel pump in an automobile is to deliver fuel from the gas tank to the fuel injector or carburetor at the necessary pressure. Fuel is drawn from the fuel tank and is propelled into the internal combustion engine through a fuel pump where the combustion of fuel occurs with air. Regardless of the external conditions, a fuel pump has to facilitate the delivery of right amount of gasoline from the tank to the engine through a fuel line at a specific pressure. In automobile engines, some fuel pumps are mechanically operated with low pressure fuel distribution, whereas others are electric pumps that push the gasoline to the engines at higher pressure.Read More

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