Driveability Diagnostics and Direct Injection
Direct injection is becoming standard on more and more late-model vehicles. These systems can be a diagnostic challenge, but with the right foundation, problems can be solved profitably. Years ago, all a low-level technician needed to diagnose a fuel problem was a set of “noid lights,” a fuel pressure gauge and maybe a meter. These
The Best Tests For Fuel Delivery Systems
The ancient Greek philosopher Heraclitus said that there is nothing permanent except change. Greek history aside, it’s easy to spot change in our current market because vehicle fuel delivery technology has evolved to include conventional, pulse-modulated and direct fuel injection fuel delivery systems, with each having a specific set of components and testing issues. In
10 Signs A Fuel Injector Needs To Be Replaced
In the past 30 years, the fuel injector has moved from the intake manifold to the combustion chamber. During this evolution, injectors have become more precise in dispensing fuel. If this precision is thrown off by restrictions, electrical problems or fuel problems, it can cause driveability issues. These are the top 10 signs fuel injectors need service or replacement.
Air Filter Fuel Trim Diagnostics
The modern engine measures two things extremely well, the amount of air going into the combustion chamber with the mass airflow sensor (MAF), and the byproducts that are generated by the combustion event with the oxygen sensor. These measurements allow the engine’s computer to put the right amount of fuel and spark into the cylinder to give the most efficient and cleanest combustion event.
Servicing GM Autoride Rear Air Suspension
The GM full-sized SUVs (Tahoe, Escalade and Avalanche) are the choice of soccer moms, diplomats and celebrities. What made these vehicles so popular was how the vehicles handle suburban and city roads. The key to this is the GM Autoride rear air suspension. Autoride comes standard on the GMC Yukon Denali and Yukon XL Denali. The product is also standard on the Cadillac Escalade, Escalade EXT and Escalade ESV on which it is known as Road Sensing Suspension. GM also offers Autoride as an option for the Chevrolet Suburban, Tahoe and Avalanche 1500, and an option for the GMC Yukon XL 1500.
Engine Fuel Trim Diagnosis And O2 Sensor Performance
A useful diagnostic tool is to determine if the fuel trim problem exists in more than one engine operating range. Fuel trim should be checked at idle, at 1,500 rpm and at 2,500 rpm. In addition to these no-load checks, drive the vehicle at various steady load conditions and watch for fuel trim variation.
Mazda Feature: Driveability And Check Engine Light Diagnostics
Import Specialist Bob Dowie takes a look at some of the more common ailments that will bring your Mazda customers into your service bay with a check engine light complaint, as he covers common DTCs, stalling and ignition issues and new technology.
Uncovering Potential Repair Issues On Mazda3
In this article, we’ll take a look at routine services on a Mazda3 and some of the more common problems that may be uncovered as they are performed. Our shop has always subscribed to 30,000-, 60,000- and 90,000-mile major service intervals with oil changes and inspections at a maximum of 5,000 miles. That may not exactly match the factory recommendations, but it works well for our customers and us, and covers all of the recommended services.
Diagnostic Solutions: Variable Camshaft Timing And Back Pressure Issues
When the topic of variable valve timing (VVT) comes up in import repair shops, few realize that the concept of increasing low- and high-speed engine torque by automatically advancing and retarding valve timing isn’t a recent development. For example, I recently discovered an old variable camshaft timing gear that I bought during the 1960s featuring a torsion spring device that retards valve timing in response to the increased rotating torque needed to turn the camshaft at higher engine speeds.
Troubleshooting Mass Air Flow (MAF) Sensors
Troubleshooting mass air flow (MAF) sensor problems can become a major headache for import technicians because the failure is usually one that involves a calibration error rather than an outright electrical or mechanical failure. Because calibration errors tend to be “gray-area” types of problems, we will begin by looking at the basics of how a “hot-wire” MAF sensor measures airflow through an engine running at various speeds and loads.
