Tech Tip: Diagnosing Fuel Pumps and Injectors
One of the first questions that should always be answered when diagnosing a fuel-related complaint on a fuel-injected engine is, "What is the fuel pressure?" All too often, technicians assume fuel pressure is "good" without actually measuring it with a gauge. If the engine runs, they assume the injectors are getting adequate fuel pressure. If the engine cranks but won’t start, and they depress the service valve on the ….
Tech Feature: Diagnosing Fuel Pumps and Injectors
One of the first questions that should always be answered when diagnosing a fuel-related complaint on a fuel-injected engine is, “What is the fuel pressure?” All too often, technicians assume fuel pressure is “good” without actually measuring it with a gauge. If the engine runs, they assume the injectors are getting adequate fuel pressure. If
Emissions Update: Understanding How Wide Ratio Air/Fuel (WRAF) Sensors Work
Instead of giving a simple rich/lean indication, wide ratio air/fuel sensors measure the “actual” air/fuel ratio. A WRAF sensor can measure mixtures that range from extremely rich to extremely lean (even straight air!). This ability allows the PCM to control fuel mixtures much more precisely, to handle much leaner fuel mixtures, to reduce emissions and
Diagnostic Dilemmas: Servicing Jeep and Ford Feedback Carburetors
Lately, it seems, more people are “going retro” by rehabilitating older cars and trucks. Perhaps it’s the longing for the simplicity of a bygone era or perhaps it’s the sentimental attachment to a particular vehicle that’s driving the retro movement. Although in the Rustbelt East, the survival rate of these vehicles is probably very low,
You Can Tune a Carburetor, but You Can’t Tuna Fish
I don’t know where the term “master engine tuner” originated, but I suspect it parallels that of “master piano tuner” because both disciplines transform apparent discord into apparent harmony. In this day of electronically managed engines, we forget that mechanically controlled spark advance curves and carburetor mixtures don’t compensate for changes in barometric pressure and
Diagnostic Dilemmas: Servicing Quadrajet Carburetors
src=”/wp-content/uploads/Articles/05_01_2008/39766Carb4jpg_00000021239.jpg” border=”0″ ” align=”right” alt=”photo 4: float level can easily be measured on the quadrajet.”/>can be measured by inserting a special Kent-Moore float level gauge into the bowl vent located just aft the choke valve. See Photo 4. Measuring the distance from the top of the bowl vent to the float and then subtracting the
Fuel Injector Service: The Basics and Beyond
and go traffic conditions. Because high underhood heat usually increases electrical and clogging failures in fuel injectors, fuel-injected vehicles driven in metro areas may generally need more maintenance than vehicles driven in rural areas. We can also generally say that many late 1980s and early 1990s fuel injectors fail more often because of poor design,
Carley’s Corner: Fuel Pump Warranty Returns Still an Issue
About a year ago, I attended a meeting of the Fuel Pump Manufacturers Council (FPMC) in Chicago. The members of FPMC are the companies who manufacture and supply fuel pumps to the aftermarket (as well as the auto makers). The purpose of the meeting was to address a serious problem that has been plaguing the
Diagnostic Solutions: Fuel System Pressure & Volume Checks
For maximum efficiency, modern import fuel injection systems require that fuel be delivered at a specified volume and pressure. Because the fuel injector’s job is to mix fuel with the intake air charge, it must produce a finely misted, conical spray pattern through the fuel injector nozzle. Lower-than-specified fuel pressures not only fail to provide
Bad Gas Update
How bad can it get? When the price of gasoline soared to over $3 a gallon after hurricane Katrina, people were shocked. They actually began to change their driving habits to conserve fuel by eliminating unnecessary trips, sharing rides to work, staying home in the evening instead of going out and doing what little they
Under Pressure: Maintaining Ford’s Electronic Returnless Fuel System
By Glen Beanard, Technical Contributor Here we go again. A simple electric pump pushing fuel up to the engine, with its pressure being controlled by a little valve, and returning the unused fuel to the tank was not good enough. Now, we need to make that all fancy by adding a new controller, adding a
Fuel Pump Diagnostics
Electric fuel pumps are a vital part of any electronic fuel injection system because achieving an accurate air/fuel mixture ratio depends upon the fuel injector receiving adequate fuel pressure and volume. Because electric fuel pumps have moving parts that wear out, they also have a relatively predictable service life and, therefore, become a predictable profit