Even with the latest technology in today's vehicles, the Engine Control Module (ECM) must still make several assumptions during operation -- including that the fuel pressure, flow rate, total pump output, fuel injectors (Fig. 1) and manifold vacuum are at manufacturer's specifications and that the fuel is contaminant-free and is not vaporized or aerated. All of these items affect the performance of the fuel system and your job of diagnosing which one may be causing a driveability condition.
The new ACDelco Fuel System Service and Diagnostics seminar (S-FC01-01.02SEM) (Fig. 2) covers the operation of all gasoline fuel system components, with the main focus on electric fuel pumps. The seminar also reviews various fuel delivery systems, such as return, returnless (demand) and electronic returnless. In addition, the seminar examines the changes in fuel delivery from port fuel injection, central multiport, and central sequential systems to the latest multiport flexible fuel injection and direct injection systems.
Fuel Pumps
In the seminar, participants will learn about three different types of ACDelco fuel pumps: turbine, roller vane and gerotor. These pumps can be high or low pressure, stand-alone or integrated into a modular assembly.
The Modular Reservoir Assembly (MRA) (Fig. 3) is designed to eliminate hydrocarbon fuel tank emissions and fuel delivery problems by retaining hot fuel in the reservoir and replenishing it with cooler fuel from the tank, providing a reservoir of fuel at all times for continuous fuel pickup.
In addition, the seminar covers various fuel issues -- contamination, composition, tank flushing -- and fuel system diagnostics. Some of the diagnostic points that are reviewed include proper fuel flow, fuel pressure, fuel volume and fuel pump current measurements.
Fuel Injectors
Other fuel components discussed in the seminar include: fuel injectors, fuel level sensors (including the latest ceramic card technology), fuel filters and fuel pressure regulators, with an emphasis on current concerns and diagnostic techniques.
In the seminar, several different designs of fuel injectors are reviewed along with their specific service requirements, including determining the condition of the electric solenoid and the mechanical operation of the injector. Typical fuel injector testing includes testing an injector's coil for electrical integrity, a mechanical flow check that actuates the injector, and an injector pulse test measuring the amount of fuel supplied to the combustion chambers.
Newer tools and systems such as the Active Fuel Injector Tester (AFIT), gasoline direct injection, and piezoelectric injectors also are discussed.
The AFIT was developed to address concerns regarding the accuracy of diagnosis on modern fuel injection systems and to help identify the root cause of driveability issues not corrected by the replacement of injectors. It completely automates the testing procedures.
One of the latest fuel delivery systems, direct injection, delivers precisely metered fuel directly to the combustion chamber where it is mixed with air (Fig. 4), unlike conventional fuel injection that mixes air and fuel that partially evaporate in the intake port of the intake manifold prior to being introduced in the combustion chamber.
New piezoelectric injectors, currently being introduced in both diesel and gasoline direct injection systems, feature piezo crystal actuators that switch five times faster than a solenoid operated injector.
Seminar participants also will review a variety of fuel system-related service and installation tips along with the latest news on fuel economy improvements.
Learn More
In addition to the Fuel System Service and Diagnostics seminar, ACDelco offers a variety of training programs in several formats covering a number of technical topics, including instructor-led training at training centers around the country as well as web-based training. Visit www.acdelcotechconnect.com and click on the Training tab for more information about available ACDelco training opportunities.
To attend the Fuel System Service and Diagnostics seminar or other seminars in your area, contact your local ACDelco distributor.
- Thanks to Mike Militello
I'd like to know more about when this seminar will be held in my area. Do you have a schedule of ACDelco seminars?
ACDelco seminars are held at local ACDelco distributors at various times. A national schedule is not available. Check with your local ACDelco distributor to find out which seminars will be held in your area.