autodiagnosticsandpublishing.com

diycardoctor.com

fuel_rail_pressure

http://www.diycardoctor.com/fuel_rail_pressure.htm

Is the rail pressurized? If not we may need a fuel pump. With the ever tightening emission standards the need to prevent hot fuel from returning to the tank became an obvious necessity. The fuel rail pressure sensor is a link in modern returnless systems, in which only one fuel line reaches the hot engine bay. The FRP sensor simply informs the ECM of fuel pressure value and it in turn regulates the furl pumps rotational speed. CONDITIONS THAT AFFECT OPERATION. Ascertain that the system is working properly.

diycardoctor.com

leak_detection_pump

http://www.diycardoctor.com/leak_detection_pump.htm

The Leak Detection Pump pumping to the end just to find what you're looking for. Modern EVAP systems have to be able to detect minute fuel vapor leaks. The leak detection pump does exactly that, pumps air into the fuel tank and charcoal canister so that the ECM can measure the system's pressure decay. Here's how it works. The LDP is seeing wider use due to its more sensitive leak detection capability. It is absolutely important to understand how the LDP works so as be able to properly diagnose the sy...

diycardoctor.com

An IAT for everyone

http://www.diycardoctor.com/an_iat_for_everyone.htm

An IAT for everyone. The IAT sensor or air-temperature sensor. Yes it is in almost every car. The IAT sensor is a cousin of the ECT (coolant sensor). It is a secondary input to the ECM. It however, could cause loss of fuel efficiency as well as the CEL (check engine light) ON. Conditions that Affect Operation. The diagnostics testing routine for the IAT is similar to the ECT. Just remember that the IAT senses air temperature instead of coolant temperature. Selective Inj. Cut-Off. GM SRS Airbag Code.

diycardoctor.com

tps_sensor

http://www.diycardoctor.com/tps_sensor.htm

The position of the throttle is very important. The TPS or throttle position sensor feeds the ECM with throttle opening and rate of change. The angle of the throttle opening is instrumental in calculating fuel delivery and ignition timing. Newer engines even have control of the valve timing, for which the TPS value is also used. The position of the throttle valve is very important. The TPS is a three wire sensor that measures the throttle plate opening. As well as its rate of change. Some manufacturers u...

diycardoctor.com

idle_control_valve

http://www.diycardoctor.com/idle_control_valve.htm

The Idle Air Control Valve, will let you breath or not . The IAC or Idle Air Control Valve has a simple job, to let a measured amount of air pass the intake throttle to thereby adjust the idle speed. A lot goes behind the scenes in this system, as the ECM has to take this air leak into account and adjust for at the injector pulse width. Here's how this works. Which is an actual PID on the scan tool. The ECM is constantly comparing the actual idle engine RPM. The first variant is the stepper motor type.

diycardoctor.com

the_ect_sensor_temperature

http://www.diycardoctor.com/the_ect_sensor_temperature.htm

The ECT sensor says - How hot it is. The ECT sensor is one of the most important components on a modern car. It tells how hot or cold the engine coolant. But, there are specifics to this sensor. Making the wrong assumption will cause trouble for you, the DIY-Tech or auto-man-woman. Remember, just because the computer says so, it doesn't mean the ECT sensor is bad. Some manufacturers use a dual scale ECT signal determined by two different pull-up resistors inside the ECM. Cold start enrichment mode. Knock...

diycardoctor.com

air_fuel_ratio_sensor

http://www.diycardoctor.com/air_fuel_ratio_sensor.htm

The AFR will inherit the earth. The AFR - A wonder of automotive technology. This little sensor will replace all modern O2 or Oxygen sensors within the next few years. Most newer vehicles now employ the AFR or air fuel ratio sensor. It is more precise and covers a wider range of air fuel mixtures. The AFR owns the modern fuel control age. The actual voltage that is generated is the difference between the O2 content of the exhaust and that of the surrounding ambient air. And more than 21 K-Ohms. The wide ...

diycardoctor.com

knock_sensor

http://www.diycardoctor.com/knock_sensor.htm

The computer has to hear the knock. The Knock-Sensor is in essence a microphone tuned to hear the pinging noise the engine produces whenever there's a problem. The knock sensor is always screwed on to the engine block for better sound reception. However, it blocks out all non-pinging engine sounds and only picks up on the actual ping. A ping is always caused by ignition out of timing or lower octane fuel, depending on the engine design. And is tuned to the specific frequency of a pinging engine. In o...

diycardoctor.com

vss_sensor

http://www.diycardoctor.com/vss_sensor.htm

My VSS is not working. I don't deserve a ticket. The ECT sensor is one of the most important components on a modern car. It tells how hot or cold the engine coolant. But, there are specifics to this sensor. Making the wrong assumption will cause trouble for you, the DIY-Tech or auto-man-woman. Remember, just because the computer says so, it doesn't mean the ECT sensor is bad. The vehicle Speed Sensor (VSS). Has the job of providing the different modules, with vehicle speed. The MAGNETIC type for the most...

diycardoctor.com

cam_sensor

http://www.diycardoctor.com/cam_sensor.htm

A position sensor just for the CAMs and CRKs. The CAM sensor or camshaft position sensor relates CAM position and rate of change. CAM and CRK synchronization is also very important and on some systems will even determine if injection takes place. The ECM simply cuts injection pulse if it sees a skewed CAM/CRK out of synch event, which is done to protect the engine. The crank ( CRK). Will affect the approach that is taken to a proper diagnostic procedure. By analyzing the signal path. Between the sensor a...