Tech Feature: Returnless Fuel Injection Systems
If you’ve tried to find the fuel pressure regulator on many late-model engines by looking in the engine compartment, you won’t find it there because the regulator has been relocated to the fuel tank. Engines with “returnless” electronic fuel injection (EFI) systems have the regulator inside the fuel tank. The regulator is part of the fuel pump assembly and is usually located downstream of the in-tank fuel filter.
Point of No Return: Returnless Fuel Injection Systems
If you’ve tried to find the fuel pressure regulator on many late-model engines by looking in the engine compartment, you won’t find it there because the regulator has been relocated to the fuel tank.
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
Hose & Reels: Reeling It In
It is said that a chain is only as strong as its weakest link. This idea applies to many things in life. Air tools and equipment are no exception. Today’s pneumatic equipment is far superior in many ways to equipment made just a few years ago. There are lighter materials and better designs, resulting in
Diagnostic Dilemmas: Servicing Quadrajet Carburetors
Introduced at the dawn of the emissions control era of the early 1960s, the “spread-bore” Rochester Quadrajet carburetor was considered leading-edge fuel delivery technology for the time. The “spread-bore” configuration consists of two small-diameter primary venturis designed to maintain high primary air velocities during normal driving for maximum fuel economy and low exhaust emissions. The
Subaru Tech Tip: Diagnosing Idle Surges on Legacy Models
If you encounter a driveability concern such as idle surges or whistling, it may be caused by carbon buildup on the Idle Speed Control (ISC) valve. In these cases, it is not necessary to replace the ISC valve. Cleaning the ISC valve could correct the condition. To clean an ISC valve, perform the repair procedure ….
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