GMC Yukon No-Cranking Complaint: The 1,300-Mile Test Drive
This month’s Diagnostic Dilemma is about the technical and professional issues involved with attempting to diagnose an extremely random no-cranking complaint on a 2003 GMC Yukon equipped with the 5.3L VIN Z engine and automatic transmission. I use the word “attempting” because if we get authorization to proceed in the next thirty days, I have
Starter and Theft Deterrent System Diagnostics
The electric starter motor took the place of the hand crank a long time ago. Although, the actual starter motor has improved quite a bit over time, its function is still the same. Just like most of the systems in today’s cars, the simplicity of the basic functions of a circuit remains the same, but
A New Look at Cooling System Technology
While changes in modern cooling system technology might not be apparent in day-to-day servicing, the fact is that auto manufacturers are continuing to increase fuel economy and power output by changing how the cooling system operates. But technical change has developed very gradually. In the beginning, a few turn-of-the-century auto manufacturers relied on a thermal-expansion
What I learned From A Repo Man
One of my guilty pleasures in life is YouTube, where anyone with a computer can create their own channel. It might be a guy living out of a motorhome and driving cross-country or a car detailer with OCD, but once I find something that peaks my interest, I will “binge” watch all their videos on
Replacing Fuel Lines
As vehicles are lasting longer, the chances the fuel lines will spring a leak are increasing. The main reason metal fuel lines fail is corrosion, but most corrosion starts when abrasive materials start to remove the paint or coating on the line. This can occur at a mounting bracket or from debris kicked up from
Nissan TPMS Service
Nissan TPMS systems began appearing in 2003 as a standard feature or option on most models. And, for the past decade, the behavior of all Nissan TPMS systems is very consistent on all models. There is only one trick to service Nissan TPMS systems, and that is to buy the right tools. A TPMS tool
Diagnostic Dilemmas: Pinball Effect: Sorting Through Multiple Codes and Problems
“My dash lights up like a pinball machine, the engine loses power for a few seconds, and then seems to run OK.” Although I’d actually been chasing this Diagnostic Dilemma for the better part of a year, this four-wheel drive 2001 Blazer equipped with the 4.3L Vortec engine and manual transmission otherwise appeared to be
Ultimate Underhood: From Mechanical Fuel Injection to Putters
Mechanical constant stream fuel injection is the pinnacle of pure mechanical engineering. The mechanic setting up the system must optimize the amount of fuel for a given throttle position, rpm and engine load. By using different pumps, jets, linkages and metering block settings, it is possible to deliver the correct amount of fuel in large
Induction Cleaning Service For Direct-Injection Vehicles
You may have seen it before: misfire codes, stumbling and suspicious fuel trim numbers. On a scan tool, the engine may show a loss in volumetric efficiency. The driver may complain about a loss of power, poor fuel economy, hard starts and a rough idle. But this is not a 12-year-old engine; it is only
Getting the Complete Picture on Converter Efficiency
Engine management systems compensate for changes in engine speed, loads and temperatures by adjusting the amount of fuel injected, spark advance/retard and even when the intake and exhaust valves open. These adjustments can only do so much. Tailpipe emissions are cut further by exhaust gas recirculation (EGR) and secondary air injection systems. The last line
Directions: 20 Years: The Past, Present and Future of Underhood Service
Automotive historians will look back on 1995 as a watershed year for the automotive industry. By September, all 1996 models had to have the same OBDII diagnostic connector under the dash, speaking the same emissions language. Around the same time in Akron, OH, Babcox Media saw the times were changing for vehicle repairs and diagnostics.
Diesel Particulate Filters
The EPA has lowered diesel fuel sulfur content from 500 ppm (parts per million) to 15 ppm. This new ultra-low sulfur fuel has been available since October 2006. All 2007 and later diesel engines must comply with the new regulations that require the reduction of nitrogen oxide (NOx) and hydrocarbons (HC) by 50% and particulate
