Engine vacuum/sensors/valves

[Genie47]

OK below is the breakdown of the vacuum/sensors and valves found in most engines today. If you found a way to fool anyone of them for better performance, contact Toyota, GM or Mercedes-Benz. Black-clad field operatives on MD500 Defender helicopters will fly to your house.

 

EEC - Evaporative Emmissions Controls

To reduce the hydrocarbon emissions, evaporated fuel from the fuel tank is routed through the charcoal cannister to the intake manifold for combustion in the cylinders. This is located behind the Air Intake, and can be replaced with an oil catch can.

 

EGR - Exhaust Gas Recirculation System

To lower the maximum combustion, a portion of the exhaust gases are recirculated through the EGR vlave to the intake manifold.

 

The EGR valve has a vacuum modulator filter, this should be checked for clogging and cleaned with an air line or replaced if clogged. Most also have a Bimetal Vacuuming Switching valve which requires checking.

 

Oxygen Sensor (lamda)

Senses oxygen levels in spent charged fuel to adjust fueling mixture as necessary. Oxygen sensors are heated in order to work.

 

ECU - Engine Control Unit

Contains a built in onboard diagnostic (OBD) system, troubles with the 'engine signal network' are detected and the engine warning light will illuminate on the dash board. A ECU check is then necessary.

 

TPS - Throttle position sensor

Tranlates the position of the throttle plate into an electrical signal, also has a sensor for open and idle positions.

 

AFM - Air Flow Meter

The AFM contains a spring loaded measuring plate, connected to a potentiometer which controls its signal to the ECU. This allows the intake air volume to be considered to control fuel injector duration and ignition advance. Older cars are usually fitted with AFM.

 

Vacuum Sensor (also known as Manifold Absolute Pressure MAP)

Converts a vacuum signal from the intake manifold to electrical signal to ECU. Used to determine basic injection duration and basic ignition advance angle. Newer cars of today are fitted with these and these vehicles also use a IATS 'intake air temperature sensor' mounted in the intake airstream.

CTS - Coolant Temperature Sensor

Works like the IATS, a variable resistor.

 

VSV - Vacuum Solenoid Valves

Operated by ECU, when electricaly energised the valve opens a vacuum passage allowing the engine vacuum to operate a component.

 

ISC - Idle Speed Control

Responds to engine conditions (coolant temps, aircon, etc) allows more through the bypass of the throttle valve to raise idleto keep ancillaries running.

 

Not necessary to describe are - Main Relay, Circuit Opening Relay, Fuel Injector Solenoid Resistor, Fuel Pump Resistor, Fuel Pump Relay.

 

So, thats a busy little system ensuring you are running the correct fuel.

Edited January 28, 2005 by Genie47

[Normal_aspirated]

mmmmh , EEC can be a D.I.Y. project.......dunno safe or not.

[Genie47]

Sure you can try but replacing it with an oil catch tank would achieve.....?

[Normal_aspirated]

where to attach the oil-catch tank to this trapped evaporated fuel inside the petrol tank? Wat i noe oil-catch tank does is to condense the vapour and store it inside itself.

[Genie47]

How much petrol you can save? Like trying to condense water in desert for drinking.

[Normal_aspirated]

well, such a water producing product (as seen in movie Dune I & II) hv been around, but will be very keen to know whether evaporated fuel system, is it feasible?

Edited January 30, 2005 by Normal_aspirated

[Genie47]

Dune?! Siao ah! If like that can, I will secretly put these things around petrol stations to capture all the fumes from people pumping petrol and use for my car w/o paying!

[Normal_aspirated]

No lah, Dunees dun drink petrol mah. In desert, they recycle their urine for drinking water, mah. Juz like us, new water...... recycled from toilet ones [laugh]

In Europe, i tot i saw in the net tat evaporated fuel combust better so produce less toxic fumes, so making "tree-huggers" people happy, mah.

Edited January 30, 2005 by Normal_aspirated