 When that control is lost, system lean/rich codes result.
Mar 2, 2010
By:Peter F. Meier
Serious racers of previous eras had a keen interest in track elevation, relative humidity and air temperature, all numbers they used to calculate relative air density.
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In NASCAR, it's about more than just speed.
Mar 1, 2010
By:Peter F. Meier
What are the challenges in designing a NASCAR brake system? A vehicle in motion accumulates kinetic energy proportional to its mass and to the square of its speed. So to stop that vehicle or to even just slow it down, that energy has to be transferred somewhere else. The easiest method is to convert that kinetic energy into heat, and that?s exactly what braking systems do through friction between the pad material and the rotor. The vehicle we?re designing for is a 3,400-pound, 800 hp rocket ship capable of speeds of nearly 195 mph. That?s a lot of energy to convert!
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The exhaust system often is overlooked as a cause of drivability problems.
Feb 1, 2010
By:Peter F. Meier
Today's exhaust system hasn't changed much from the ones I grew up on. It still is designed to reduce exhaust noise to an acceptable level and to pass the combusted gases away from the cabin area for safety. It has always been tuned to maximize the scavenging of the exhaust gases from the combustion chamber, and the only real new addition since I started in the mid-1970s is the catalytic converter.
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Improving overall fuel economy is a matter of small gains in a variety of areas.
Jan 4, 2010
By:Peter F. Meier
Ever hear of the government's Corporate Average Fuel Economy (CAFE) regulations? First enacted by Congress in 1975 in response to the oil embargo of the era, it sets fuel economy standards for passenger cars and light trucks sold in the United States. CAFE regulations will climb rapidly by 2016, with requirements calling for 42 mpg for passenger cars and 26 mpg for light trucks, for an average of 35.5 mpg.
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Modern electronics paves the way for improved driver safety.
Dec 29, 2009
By:Peter F. Meier
Vehicles today feature more safety technologies to keep vehicles from being in an accident, including changes to the brake systems, stability control and new blind spot detection. Here's a description of some of the systems you'll see in your bays today.
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ECMs are good at telling you what to fix.
Nov 1, 2009
By:Peter F. Meier
An OBDII Engine Control Module (ECM) has one primary function: keeping vehicle emissions in line. It's gotten so good at it that many states now rely on what the ECM has to say when certifying vehicles in meeting state emissions requirements.
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Troubleshooting drivability issues should start with making sure the engine is healthy.
Oct 13, 2009
By:Peter F. Meier
The miss was just barely apparent at idle. As soon as the throttle plate was opened, even slightly, the miss went away. Out on the road, the engine performed perfectly at any speed, under any load. The culprit turned out to be a burnt exhaust valve on the rear bank of this Chrysler minivan causing just a slight loss of compression, but I didn't find it until I had nearly exhausted all other possibilities.
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No matter the power window design, it still has to open and close the glass.
Oct 1, 2009
By:Peter F. Meier
A window that won't roll back up is not the only power window complaint you may face. Other common faults are windows that only move partially through their travel before grinding to a halt, work in one direction only or no longer respond to their auto up/down feature. A few simple checks, however, can often quickly and successfully locate the cause of these common problems.
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Misfires occur when the combustion process is incomplete, so you need to find what's missing.
Oct 1, 2009
By:Peter F. Meier
Misfires are a common drivability issue. If the misfire rate exceeds the programmed threshold, the Engine Control Module (ECM) will record the problem and turn on the Malfunction Indicator Lamp (MIL). Misfires occur when the combustion process is not as it should be. Any factor, therefore, that affects this process is suspect when it comes to diagnosis.
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