AGM Batteries And Testing
Two of the greatest changes we’ve seen in starting/charging systems during the past few model years have been the expanded use of the Absorbed Glass Mat (AGM) battery as standard equipment and the accelerating pricing structures of both AGM and conventional flooded-cell batteries.
Parasitic Drain: 2003 Chevrolet Tahoe
This month’s Diagnostic Dilemma concerns a 2003 Chevrolet Tahoe with a parasitic battery drain that leaves it with a dead battery. The first step in diagnosing a parasitic drain is interviewing the customer to determine the average number of days and the driving conditions under which the battery drains.
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 enough fuel for combustion at larger throttle openings, but may also introduce an uneven air/fuel charge distribution into the combustion chamber itself, which usually results in hard starting, hesitation and reduced power output.
Chrysler Transmission: The Case Of The Shiftless 48RE
This month’s Diagnostic Dilemma concerns a 2005 Dodge 3500 SLT truck equipped with the Chrysler 48RE automatic transmission with three forward speeds and overdrive. It originally came into the shop with a broken band, but after the rebuilt transmission was installed and road-tested, the 48RE failed to shift out of first gear.
Danger, Will Robinson! Intermittent Loss Of Power
This month’s Diagnostic Dilemma turns the page back to September 10, 2015 when I got a phone call from a local undercar shop inquiring if I had the tools to check the ECM connector pin fit on a 2012 Chevrolet Impala with the flex-fuel, 3.6L gasoline direct fuel injection engine. In response to an intermittent loss of power complaint, the shop had found a technical service bulletin (TSB) indicating that loose PCM connections can cause a loss of fuel pressure on the GDI engine’s high-pressure fuel rail and set codes P00C6 and P228C.
ECM Diagnostics: Troubleshooting P1518 Codes
ECM diagnostics can be a challenge because you often find yourself working after the fact. As described in the July 2015 issue of Underhood Service (“The 1,300-Mile Test Drive”), a seemingly routine loss of power and a no-cranking, no-instrument cluster, no-scan-tool communication complaint on a 2003 GMC Yukon, VIN Z 5.3-liter flex fuel engine turned out to be a major Diagnostic Dilemma.
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
Cylinder Head Gasket Service Essentials
This month, we’re going to discuss cylinder head gasket installation using a 2002 Hyundai Accent with the VIN “C,” 1.6L engine as an example. As with everything in modern engine mechanics, cylinder head gasket design has become more sophisticated than in years past. Aluminum generally expands at a slightly higher rate than cast iron and,
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
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
Diagnostic Dilemmas: Chrysler Sebring Code P2173 Caused by Vacuum Leak NOT Gaskets
In this month’s Diagnostic Dilemma, I found myself looking into an intermittent fast idle complaint on a 2008 Chrysler Sebring equipped with the 3.5L, V6 engine. The car was in good condition and with approximately 130,000 miles on the odometer. My client shop owner had retrieved some “throttle sensor codes,” which prompted him to replace
Diagnostic Dilemma: The Case of the Missing Code
When doing mobile diagnostic work, no-code stalling complaints are a major part of your agenda. In most cases, the client shop is simply too busy to duplicate the failure or, in some cases, a long test drive will yield nothing in the way of useful scan tool data. With many no-code stalls, all you’re going
