List of sensors, solenoids, and valves that affect engine performance
08-20-2015, 10:12 PM
#1
Senior Member
Thread Starter
List of sensors, solenoids, and valves that affect engine performance
This may be common knowledge for many people. I have been looking for a straightforward list of the sensors, valves, solenoids, and what-not that are typically found on many of our older F150 trucks but never could find one. So, I made one in hopes that it may helps someone else. I'm sure I overlooked a few here and there so please feel free to add to the list and make corrections. I wish I could include pictures of what each piece looks like for each year model involved but that would have made for a very long and very involved post. Likewise, I wish I knew the location for each item on trucks other than my 95 XLT. Because I don't, I just put the typical location.
So, without further ado, here is the list:
Anti-lock Brake Sensor (ABS) (aka VSS, or “Vehicle Speed Sensor”): This sensor measures transmission/transaxle output or wheel speed. The data from the sensor is sent to the ECM so to optimize engine functions such as ignition timing, AF ratio, and transmission shift points. It is often found on the rear differential above where the driveshaft connects.
Carbon Canister Purge Control Valve: This valve is part of the emission system. It allows fuel vapors in the carbon canister to be returned to the engine to be burned off. It is a cylinder device with an electrical connector and vacuum hose attached, and can be found near the EGR valve.
Exhaust Gas Recirculation (EGR) Valve: The EGR valve recirculates a portion of the engine’s exhaust gasses back into the engine cylinders for the purpose of reducing nitrogen oxide emissions. It is usually found towards the front of the engine, bolted often (but not always) on the passenger side of the engine. It will have a vacuum hose attached to the top or side, the EGR valve position sensor (see below) attached to it, and a pipe of sorts coming off the bottom, leading towards the back of the engine.
Exhaust Gas Recirculation (EGR) Valve Position Sensor: This sensor detects the movement and position of the EGR valve pintle by detecting the pressure caused by the exhaust gas flow through the EGR passage. It is found mounted to the EGR valve.
Exhaust Gas Recirculation (EGR) Valve Regulator (EVP) Solenoid: This solenoid regulates the vacuum supply to the EGR valve. The solenoid contains a coil that magnetically controls the position of a disc in order to regulate the vacuum. As the duty cycle to the coil increases, the vacuum signal passed through the solenoid to the EGR valve also increases. Vacuum not directed to the EGR valve is vented out through the solenoid vent on the device. It is often found mid-way along the engine on the top, near the AIRD/AIRB solenoids, and perhaps near the coil. It will have vacuum hoses attached to it.
Engine Control Unit (ECU): This is an electronic device that controls and monitors various sensors, etc. in the vehicle so to achieve optimum performance. It, along with the TCU, makes up the powertrain control module and is located in the cab, usually behind a kick panel.
Engine Coolant Temperature (ECT) Sensor (aka Coolant Temperature sensor): This sensor measures the temperature of the engine coolant in the engine and allows the ECU to adjust the fuel injection and ignition timing accordingly. On some vehicles, the sensor may also be used to switch on the electric cooling fan and may aid in providing coolant temperature data to the dashboard. It is usually found on the engine block near the thermostat.
Fuel Pressure Regulator: This device controls the fuel pressure going to the fuel injectors through a vacuum line attached to the outside of the regulator. The vacuum opens a diaphragm inside the regulator to control the pressure of the fuel going into the injectors. It is found on the back of the fuel rail. It has a vacuum hose attached to it.
Idle Air Control (IAC) Valve: The IAC valve controls the engine’s idling RPM by restricting the amount of air flowing through the valve’s body. Electrical current produced by the movement of a plunger inside the valve is transmitted to the ECU, allowing the ECU to effectively control the amount of air passing through the throttle. It is found on the throttle body.
Intake Air Temperature (IAT) sensor (aka Air Charge Temperature (ACT) Sensor: This sensor monitors the temperature of the air going into the engine and allows the ECU to adjust the ignition timing and fueling accordingly. It is found in the air tube between the air filter and the throttle body.
Knock Sensor (aka Detonation sensor): This sensor creates a voltage signal based on the vibrations caused by detonation. The computer uses this signal to slow down the timing when spark knock occurs. It is usually found mounted to the engine block on the back side of the engine.
Manifold Absolute Pressure (MAP) Sensor (pre—94): This sensor converts engine vacuum/manifold pressure to an electrical signal so the computer knows how much load the engine is under for the purposes of fuel delivery and timing control. It is often (though not always) found mounted to the firewall on the passenger side.
Mass Air Flow (MAF) Sensor (94—up): This sensor measures the amount of air flow entering the intake manifold using a heated grid or wire so to allow for proper fuel control. It is located near the air filter on the air intake tube.
Oil Pressure Sending Unit: The oil pressure sending unit controls the oil pressure gauge in the dashboard by activating the gauge when pressure is detected by the unit. As the unit detects pressure, switch contacts in the unit carry a signal to the ECU and then to the oil pressure gauge. It is located on the engine block, usually near the oil filter.
Oxygen (O2) Sensor (aka HEGO – “Heated Exhaust Gas Oxygen sensor”): This sensor monitors how much unburnedoxygen is in the exhaust as the exhaust exits the engine as a way of gauging the fuel mixture. It tells the ECU if the fuel mixture is burning rich (less oxygen) or lean (more oxygen). It is often located on the exhaust pipe just below the manifold but before the catalytic converter.
Positive Crankcase Ventilation (PCV) Valve: This is a one-way valve that works with a vacuum source to pull crankcase gases back into the engine to be burned. This reduces pressure in the crankcase and helps reduce emissions. It is located on the valve cover and has a vacuum line attached to it.
Secondary Air Injection (AIRB/AIRD) Solenoids: The Secondary AIR Injection Solenoids make up an assembly that contains two normally closed vacuum solenoids. One solenoid controls the AIR Bypass (AIRB; aka TAB, or Thermactor Air Bypass) valve and the other solenoid controls the AIR Diverter (AIRD; aka TAD, or Thermactor Air Diverter) valve. Both solenoids vent when de-energized. They are supplied by the intake manifold vacuum and controlled by the Powertrain Control Module. They are often found mid-way along the engine on the top, near the EVP solenoid, and perhaps near the coil. They will have vacuum hoses and electrical connectors attached to it.
Throttle Position Sensor (TPS): This sensor reports the position of the gas pedal (and essentially, the throttle) to the ECU so that the ECU can calculate the amount of air flow to the engine and the amount of fuel to be injected for the required ratio of air-fuel mixture. It is usually found on the underside of the throttle body. It will have an electrical connector attached to it.
Thick Film Ignition (TFI) Module: This device is an ignition-system component that regulates the electrical current that controls the air-fuel mixture going into each cylinder. It is located on the distributor and will have a 4- or 5-wire electrical connector attached to it.
Transmission Control Unit: This is a device that monitors a variety of sensors on the transmission system so to achieve optimum performance, shifting, and fuel economy. It, along with the ECU, makes up the powertrain control module and is located in the cab, usually behind a kick panel.
So, without further ado, here is the list:
Anti-lock Brake Sensor (ABS) (aka VSS, or “Vehicle Speed Sensor”): This sensor measures transmission/transaxle output or wheel speed. The data from the sensor is sent to the ECM so to optimize engine functions such as ignition timing, AF ratio, and transmission shift points. It is often found on the rear differential above where the driveshaft connects.
Carbon Canister Purge Control Valve: This valve is part of the emission system. It allows fuel vapors in the carbon canister to be returned to the engine to be burned off. It is a cylinder device with an electrical connector and vacuum hose attached, and can be found near the EGR valve.
Exhaust Gas Recirculation (EGR) Valve: The EGR valve recirculates a portion of the engine’s exhaust gasses back into the engine cylinders for the purpose of reducing nitrogen oxide emissions. It is usually found towards the front of the engine, bolted often (but not always) on the passenger side of the engine. It will have a vacuum hose attached to the top or side, the EGR valve position sensor (see below) attached to it, and a pipe of sorts coming off the bottom, leading towards the back of the engine.
Exhaust Gas Recirculation (EGR) Valve Position Sensor: This sensor detects the movement and position of the EGR valve pintle by detecting the pressure caused by the exhaust gas flow through the EGR passage. It is found mounted to the EGR valve.
Exhaust Gas Recirculation (EGR) Valve Regulator (EVP) Solenoid: This solenoid regulates the vacuum supply to the EGR valve. The solenoid contains a coil that magnetically controls the position of a disc in order to regulate the vacuum. As the duty cycle to the coil increases, the vacuum signal passed through the solenoid to the EGR valve also increases. Vacuum not directed to the EGR valve is vented out through the solenoid vent on the device. It is often found mid-way along the engine on the top, near the AIRD/AIRB solenoids, and perhaps near the coil. It will have vacuum hoses attached to it.
Engine Control Unit (ECU): This is an electronic device that controls and monitors various sensors, etc. in the vehicle so to achieve optimum performance. It, along with the TCU, makes up the powertrain control module and is located in the cab, usually behind a kick panel.
Engine Coolant Temperature (ECT) Sensor (aka Coolant Temperature sensor): This sensor measures the temperature of the engine coolant in the engine and allows the ECU to adjust the fuel injection and ignition timing accordingly. On some vehicles, the sensor may also be used to switch on the electric cooling fan and may aid in providing coolant temperature data to the dashboard. It is usually found on the engine block near the thermostat.
Fuel Pressure Regulator: This device controls the fuel pressure going to the fuel injectors through a vacuum line attached to the outside of the regulator. The vacuum opens a diaphragm inside the regulator to control the pressure of the fuel going into the injectors. It is found on the back of the fuel rail. It has a vacuum hose attached to it.
Idle Air Control (IAC) Valve: The IAC valve controls the engine’s idling RPM by restricting the amount of air flowing through the valve’s body. Electrical current produced by the movement of a plunger inside the valve is transmitted to the ECU, allowing the ECU to effectively control the amount of air passing through the throttle. It is found on the throttle body.
Intake Air Temperature (IAT) sensor (aka Air Charge Temperature (ACT) Sensor: This sensor monitors the temperature of the air going into the engine and allows the ECU to adjust the ignition timing and fueling accordingly. It is found in the air tube between the air filter and the throttle body.
Knock Sensor (aka Detonation sensor): This sensor creates a voltage signal based on the vibrations caused by detonation. The computer uses this signal to slow down the timing when spark knock occurs. It is usually found mounted to the engine block on the back side of the engine.
Manifold Absolute Pressure (MAP) Sensor (pre—94): This sensor converts engine vacuum/manifold pressure to an electrical signal so the computer knows how much load the engine is under for the purposes of fuel delivery and timing control. It is often (though not always) found mounted to the firewall on the passenger side.
Mass Air Flow (MAF) Sensor (94—up): This sensor measures the amount of air flow entering the intake manifold using a heated grid or wire so to allow for proper fuel control. It is located near the air filter on the air intake tube.
Oil Pressure Sending Unit: The oil pressure sending unit controls the oil pressure gauge in the dashboard by activating the gauge when pressure is detected by the unit. As the unit detects pressure, switch contacts in the unit carry a signal to the ECU and then to the oil pressure gauge. It is located on the engine block, usually near the oil filter.
Oxygen (O2) Sensor (aka HEGO – “Heated Exhaust Gas Oxygen sensor”): This sensor monitors how much unburnedoxygen is in the exhaust as the exhaust exits the engine as a way of gauging the fuel mixture. It tells the ECU if the fuel mixture is burning rich (less oxygen) or lean (more oxygen). It is often located on the exhaust pipe just below the manifold but before the catalytic converter.
Positive Crankcase Ventilation (PCV) Valve: This is a one-way valve that works with a vacuum source to pull crankcase gases back into the engine to be burned. This reduces pressure in the crankcase and helps reduce emissions. It is located on the valve cover and has a vacuum line attached to it.
Secondary Air Injection (AIRB/AIRD) Solenoids: The Secondary AIR Injection Solenoids make up an assembly that contains two normally closed vacuum solenoids. One solenoid controls the AIR Bypass (AIRB; aka TAB, or Thermactor Air Bypass) valve and the other solenoid controls the AIR Diverter (AIRD; aka TAD, or Thermactor Air Diverter) valve. Both solenoids vent when de-energized. They are supplied by the intake manifold vacuum and controlled by the Powertrain Control Module. They are often found mid-way along the engine on the top, near the EVP solenoid, and perhaps near the coil. They will have vacuum hoses and electrical connectors attached to it.
Throttle Position Sensor (TPS): This sensor reports the position of the gas pedal (and essentially, the throttle) to the ECU so that the ECU can calculate the amount of air flow to the engine and the amount of fuel to be injected for the required ratio of air-fuel mixture. It is usually found on the underside of the throttle body. It will have an electrical connector attached to it.
Thick Film Ignition (TFI) Module: This device is an ignition-system component that regulates the electrical current that controls the air-fuel mixture going into each cylinder. It is located on the distributor and will have a 4- or 5-wire electrical connector attached to it.
Transmission Control Unit: This is a device that monitors a variety of sensors on the transmission system so to achieve optimum performance, shifting, and fuel economy. It, along with the ECU, makes up the powertrain control module and is located in the cab, usually behind a kick panel.
Last edited by fosgate3; 08-20-2015 at 10:17 PM.
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08-21-2015, 12:17 AM
#2
Oooo a Custom Title.
Very good list. The only thing I see that could be changed is the TFI module. Not all of them are on the distributor. My 96 has it on the driver side firewall near the ECU and fuse box.
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fosgate3 (02-11-2022)
08-21-2015, 01:31 AM
#3
Senior Member
Subsection #1: Transmission
Manual Lever Position Sensor aka Neutral Safety Switch:
A sensor mounted to the shift linkage on the E4OD transmission. Once out of adjustment or failing begins, truck will have hard upshifts (similar to getting rearended), motor will rev high, truck will act as though driving down the road it falls out of gear.
If the driver has any thought or inkling that the tranny is "going out", change this sensor first. It will make you 😃!
Manual Lever Position Sensor aka Neutral Safety Switch:
A sensor mounted to the shift linkage on the E4OD transmission. Once out of adjustment or failing begins, truck will have hard upshifts (similar to getting rearended), motor will rev high, truck will act as though driving down the road it falls out of gear.
If the driver has any thought or inkling that the tranny is "going out", change this sensor first. It will make you 😃!
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fosgate3 (02-11-2022)
04-23-2018, 12:26 PM
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This forum is for '87-96 trucks, so that's not relevant.