Gary Goms, Author at UnderhoodService - Page 2 of 25
~
Diagnostic Dilemmas: From Here To There In A Snow-Plowing Chevrolet

In this installment of Diagnostic Dilemmas, we’re diagnosing idle air control problems by pursuing a no-code, cold-idle speed control condition on a 2002 Chevrolet 2500HD four-wheel drive pickup. Owned by a small local construction company, this U-code, 6.0-liter Chevrolet hauler performs admirably during the summer towing trailers and hauling heavy construction tools in its roomy, all-steel utility bed. During the winter, it plows snow in local commercial parking lots and on private mountain roads. Due to their simplicity and reliability, we still see thousands of these formidable workhorses performing their duties across our great country.

Giving It The Gas: When The Fuel Pump Isn’t The Problem

The most famous last words in automotive diagnostics are, “We’ve always done it this way.” In many cases, “always done it this way” consists of diagnosing a fuel pump by squirting some type of liquid or gaseous hydrocarbon into the air intake. Case in point, a 2011 Nissan Rogue had suddenly stalled on a busy summertime highway.

The Diagnostic Shell Game: Why The ECM Can’t See A No-Code Stalling Complaint

Remember the old carnival game where a dealer hides a pea under one of a half-dozen walnut shells? After the dealer artfully shuffles the six shells, you’re supposed to pick the shell with the pea hidden under it. Good luck with that. As veteran diagnostic technicians know, diagnosing a no-code intermittent stalling complaint can be like playing the old carnival shell game. We know it’s one of maybe six sensors, but why can’t we find the diagnostic trouble code (DTC) that tells us where to find the pea?

The No-Code Conundrum: The Art Of Diagnosing What The PCM Can’t See

Doing mobile diagnostics, I obviously get more than my share of no-code driveability problems. Case in point, I was asked by a client shop to “take a quick look” at a stalling complaint on a 2003 Ford Explorer with a cable-operated throttle.

The Art of Diagnosing What the PCM Can’t See

The difficulties of diagnosing no-code drivability problems are best summed up by one of Yogi Berra’s famous quotes, “When you come to a fork in the road, take it.”

Rethinking Fuel Pump Diagnostics And Sensors

The technician diagnosed the 2011 Rogue as a bad fuel pump by squirting propane into the air intake. With propane, the engine runs, without propane, it stalls. But, after the fuel pump was replaced, the Rogue exhibited the same problem, which was a very slow, unsteady idle followed by an engine stall.

The Duramax Dilemma: Injector Circuit Diagnostics

The owner of this GM Duramax was headed to Montana on vacation with his family and camper trailer in tow. After stopping for lunch, the owner was dismayed to find that his Duramax immediately went into “limp mode” as the engine started.

The Evolving Oil Change Market

The only constant in the oil change business is change itself, especially if you’re trying to maintain an inventory of engine oil for all makes and models of vehicles.

Computer-Controlled, ‘Smart’ Charging System Strategies: Why Volts Are Smart, But Amps Are Smarter

When diagnosing a charging system on any modern import, think “smart.” I learned this lesson several decades ago when repairing a cranking, no-start condition on a 1989 Honda Civic, which was equipped with one of the first “smart” charging systems. After verifying fuse continuity, I discovered that excessively high charging voltage had destroyed the Honda’s Engine Control Module (ECM).

Catching The Electron Flow: Multimeters And Fuse Box Diagnostics

Gary Goms explains why the multimeter is the first tool he reaches for in his diagnostic tool box when diagnosing electrical system problems.

Troubleshooting And Sorting Out Multiple DTCs At The Penny Arcade

It is late Thursday afternoon in mid-May and tourist season is just beginning in Colorado’s High Country. After finishing one mobile diagnosis, I was asked to look at another – a 2003 Honda Element with a no-cranking condition that had just been dropped off at my client shop’s busy parking lot by an owner who was now stranded 2,000 miles away from home.

Following The ‘Electronic Trail’ As A Means To Solve PCM-Related Problems

Leave your wrenches in your toolbox because in this month’s Diagnostic Solutions, we’re going to explore how to diagnose many common powertrain control module (PCM)-related driveability and electrical problems by following what I call The Electronic Trail.