Showing posts from March, 2014

Control Your Cruise

Modern cars go much further in preventing driver fatigue than the cars from years past. Anything the engineers can do to make the car more pleasant to drive is a good thing. One feature that does this very well but that has actually been around for a very long time is cruise control. This feature is not new but it has evolved tremendously and really doesn’t function at all like it used to. The first cruise control systems used canister with a rubber diaphragm attached to a cable that would hold the throttle open when engine vacuum was applied to one side of the diaphragm. When the driver wanted to increase the set speed a vacuum solenoid would allow more vacuum in to act on the diaphragm. When the driver would hit the brake a valve attached to the brake pedal would let all the vacuum out and the throttle would snap shut. Newer systems started using more electronic controls such as a small electric solenoid that could pull on a cable to hold the throttle open at the set spe

Deceptive Lights: Check Engine Light

Everyone out there has probably had a car that had a check engine light come on at some point. Some of you might have even had one blink at you furiously. Sometimes, the illumination corresponds perfectly with the engine running rough, fuel economy falling into the basement, or the transmission shifting funny. Sometimes nothing seems different in the way the vehicle runs at all. Either way, anytime the light illuminates it means something is broken. However, when the check engine light illuminates, it probably doesn’t have anything to do with the engine itself. This can make the check engine light deceptive. This little light of frustration and angst will illuminate anytime the engine control computer sees a failure in the powertrain controls that will cause an increase in vehicle emissions greater than 150% of the federal test standard. This means if something breaks and it causes your car to potentially pollute more than normal, the computer will turn the light on. Most of th

Monitoring the Thermostat

This is not that control panel on the wall of your house that you argue with your significant other over where the ideal setting should be. The thermostat is a control valve within the cooling system of your engine. Like the control panel for the furnace in your house, the engine thermostat is used to regulate temperature. When the engine is cold the thermostat is closed, so coolant flow is restricted. This allows the coolant to heat up much more quickly because it cannot make its way out to the radiator where heat is released from the coolant into the outside air. The thermostat is located at the coolant outlet pipe coming from the engine going to the radiator. Normal engine operating temperature is about 190 to 200 degrees F. Once the engine gets to a temperature close to this, the thermostat will open automatically. Most thermostats contain some kind of device that expands and contracts with temperature. When this thermally reactive unit gets hot it pulls