Diagnostic Solutions: Modern Spark Plug Diagnostics, The ‘Art And Science’ Of Reading Plugs
With the advent of electronic engine management systems, “reading” spark plugs has become something of a lost art. In the days of mechanical carburetors and distributors, the color and texture of the spark plug’s insulator could provide important information about the air/fuel ratio, spark timing and cylinder condition.
Diagnosing Exhaust Gas Recirculation (EGR)
Exhaust gas recirculation is the dilution of the air/fuel mixture to control amounts of exhaust gas. Since exhaust gas does not burn, this lowers the combustion temperatures and reduces NOx emissions from the engine. At lower combustion temperatures, very little of the nitrogen in the air combines with oxygen to form NOx. Most of the nitrogen is simply carried out with the exhaust gases.
Servicing The GM, Isuzu Duramax Diesel Engine
The question that I often hear about the Duramax is “What kind of problems do you see with these engines?” I have to admit that these engines have a great reputation. While some problems have plagued a few of the Duramax engines, there hasn’t been anything as detrimental as what other manufacturers have had to deal with. There are always going to be issues with anything that has to do with internal combustion. The best way to examine the Duramax would be to break down the engines by their generation and evaluate issues of each.
Tech Tip: Chrysler’s Fuel Pressure Is OK, but Codes P0172 and P0175 are Detected
Applies To: 1998-2004 Intrepid 2.7L 1999-2004 Concorde 2.7L 2001 LHS 3.5L 2001-’04 Sebring 2.7L 2002 300M 3.5L 2002-’04 Intrepid 3.5L and Stratus 2.7L 2003-’04 Concorde 3.5L 2003 Stratus 2.4L Customer Concern: Trouble codes P0172 and P0175; fuel pressure is OK. Potential Causes: Camshaft Timing Oxygen (O2) Sensor Exhaust Gas Recirculation (EGR) Valve Tests/Procedures: 1. Test
Diagnosing A 2011 Chrysler Town & Country With Trouble Code P0152
Verify the wiring to the O2 sensors is normal. These sensors will normally switch between 2.5 volts and 3.5 volts when they are working correctly. The sensor ground will have 2.5 volts on it and this is normal for this vehicle.
Diagnostic Solutions: Contaminated Fuel Can Wreck Havoc On Fuel Delivery Systems
Import Specialist Contributor Gary Goms discusses how contaminated fuel can mimic the symptoms produced by defective fuel pumps, fuel injectors and fuel control components like mass air flow (MAF) sensors. Although cases involving contaminated gasoline are relatively rare nowadays, they still occur. In many cases, the technician has replaced the fuel pump or MAF sensor to address a P0171/P0174 “lean-condition” DTC with no result.
Servicing 6.0L Power Stroke Engines
If there is one engine that plagues the mid-size diesel world, you would have to say that it is the 6.0L Power Stroke. This engine has the worst repair history that has plagued and continues to plague Ford truck owners today. Even though the engine was only produced from 2003 to 2008, truck buyers often steer away from these engines when purchasing a diesel truck.
Volkswagen Tech Tip: Check Engine Light Is On With Fault Code P0420
If you encounter a check engine light on with a fault code P0420 stored in the fault memory, this may be the result of a defective catalytic converter.
Phaser-Style Variable Valve Timing System Controls And Operation
Phasers commonly can be found on just the exhaust cam or on both the intake and exhaust cams.
Tech Feature: Venturing Into GM Duramax Diesel Service
Back in the 1990s, GM wasn’t making too many waves in the diesel truck market. The 6.2L and 6.5L engines had been around for sometime, but they were no match for the release of the Cummins 6BT in the Dodge truck in 1989 and the Ford Powerstroke in 1994.