FUELS

Basic function
The process of determining the necessary amount of fuel, and its delivery into the engine, are known as fuel metering. Early injection systems used mechanical methods to meter fuel (non electronic, or mechanical fuel injection). Modern systems are nearly all electronic, and use an electronic solenoid (the injector) to inject the fuel. An electronic engine control unit calculates the mass of fuel to inject.
Modern fuel injection schemes follow much the same setup. There is a mass airflow sensor or manifold absolute pressure sensor at the intake, typically mounted either in the air tube feeding from the air filter box to the throttle body, or mounted directly to the throttle body itself. The mass airflow sensor does exactly what its name implies; it senses the mass of the air that flows past it, giving the computer an accurate idea of how much air is entering the engine. The next component in line is the Throttle Body. The throttle body has a throttle position sensor mounted onto it, typically on the butterfly valve of the throttle body. The throttle position sensor (TPS) reports to the computer the position of the throttle butterfly valve, which the ECM uses to calculate the load upon the engine. The fuel system consists of a fuel pump (typically mounted in-tank), a fuel pressure regulator, fuel lines (composed of either high strength plastic, metal, or reinforced rubber), a fuel rail that the injectors connect to, and the fuel injector(s). There is a coolant temperature sensor that reports the engine temperature to the ECM, which the engine uses to calculate the proper fuel ratio required. In sequential fuel injection systems there is a camshaft position sensor, which the ECM uses to determine which fuel injector to fire. The last component is the oxygen sensor

Testing

We test vacuum and fuel pressure during engine runing with no load and under load.

40 psi (fuel pressure) was no load with        -11 psi (vacuum)
50 psi (fuel pressure) was under load with      0 psi (vacuum)

Alternator off car testing and Startermotor off car

Rotor winding to ground test:

Components: Two slip rings

Function: Receive power from regulator through two brushs (positive and negative) to make magnetic field between rotor and stator. Power receiver componet.

Set the meter on kilo Ohms. Place the Black lead on the center on the Slip ring. Red lead on center of the Rotor shaft. There should be no circuit between the rotor shaft and the slip ring. The meter should read infinity. If there is a circuit the rotor winding has shorted to ground and will need to be replaced.

The meter should  read infinity

Spec           Meter reading            Pass/Fail

Infinity             Infinity                       Pass

Rotor winding internal resistance test: 

Set the meter on Ohms, test for internal meter resistance by touching the two leads together. Place one end of each lead on the slip rings as indicated to obtain reading. 

The reading specification is 2 ohms to 6 ohms

Spec               Meter reading                Pass

2-6 ohms           3.6 ohms                     Pass

Testing stator winding resistance: 

Components: Coil wire teminal

Function: Power out put teminal

Set meter on Ohms, test for internal meter resistance by touching the two leads together. Select the common terminal (the one with the most wires attached) of the stator winding terminals A to D. Connect the Black lead to the common point. connect the Red lead to the other terminal one after the other.

Their resistance they should all be approximately the same from 0.0 ohm to 0.2 ohms.

Spec                                Meter reading                                Pass/Fail

0.0-0.2 ohms                          0.9                                             Pass

0.0-0.2 ohms                          0.8                                             Pass

0.0-0.2 ohms                          0.9                                             Pass

Testing the rectifier positive diodes:  Component: Rectifier (diode)

Function: Same as a diode, only let power go one way, change power from AC to DC.

Use the meter on diode test mode. Put the Black lead on B Terminal. Then touch the Red lead on each of the P terminals and record the reading.

The resistance should be low.

Results for Positive diode testing with Black lead on B.

No.      Spec     0.5 VD to 0.7 VD         Pass/Fail

1                      0.516                                Pass

2                      0.513                                Pass

3                      No reading                        Fail

4                      0.513                                Pass

No.     Spec   Infinity            Pass/Fail

1              Infinity                    Pass

2              Infinity                    Pass

3              Infinity                    Pass

4              Infinity                    Pass

                        

Diode testing

Use the Multi meter to check flow
Swap LED's terminal if LED doest work.
Lose one terminal of LED, connect to Multi meter, make current flow through the Multi meter.

1) Voltage drop across Resistor and Diedo.
2) Amp flow the diedo
3) Bolyshr sy poert supply
4) Add the voltage drop from Resistor and diedo.

we got : A] 0.1V at resistor and 11.9V at diedo

             B] 0.03A at diedo.

             C] 12V at power supply.
             D]11.9V at diedo and 0.1V at Resistor.


Logic Probe Construction

Logic Probe components

A 12 volt power supply
Digital voltmeter
A soldering iron
Brass Rod 150 mm long
Red LED    
Green LED 
Black wire 2 meters long

Red wire 2 meters long
2 resistors 1k ohm
Red alligator clip
Black alligator clip
100 mm plastic tube 7mm ld

Shrink tubing:Black 2.4mm diameter, about 300mm long
Red 6.4mm diameter, about 175mm long
Black 12.7mm diameter, about 125mm long

Soldering the parts:

The LED's, 1 kΩ resistors, and wire are then soldered together





Using the small heat shrink insulate both resistors and LED legs,(from the Black and Red wires to as

 possible to the LED)

Before soldering the uninsulated legs of LED's to the brass rod, cut two 15mm pieces of the blue heat shrink and slide them both over the red and black wire and up onto the rod, get the LED's into approximately the correct position then heat the heat shrink.This will support the weight of the wires and prevent the insulated legs of the LED's breaking off.

Position the LED's to sit just above the rod,making sure that the insulation protects the insulated legs of the LED's from the brass rod.Twist the uninsulated legs of the LED's individually around the brassrod and solder to the tined section.

Fitting the plastic tube:

Select the 100mm length of 10mm diameter plastic tube and cut a groove out of one end. This groove needs to be as long as the two LED's are in line, plus 5mm that when fitted will extend past the LED's.

Improving the appearance: 

To improve the appearance cut 20mm length of the 10mm black Heat Shrink.Slide it on from the pointed end of the brass rod. It may be necessary to squeeze the plastic tube together so the heat shrink will slide right up close to the green LED.

Cut 20mm lengths of red heat shrink and fit to both ends of the probe ,this will pull the black Heat Shrink onto the brass rod and the wire tightly.

Fitting Alligator clips:

 

Remove the plastic covers from both the clips and install the correct way around on the appropriate coloured wires. Strip the insulation and twist about 10mm of each wire tightly. Insert the twisted end of the wire through the hole in the clip, bend and secure the insulated section of the wire in the claws provided.Cut off the excess twisted wire and solder joints.

 

 

Testing:

This tester is only for 24 volts or less,DC volts only. Connect the red clip to battery positive and the black clip to battery negative.Both red and green LEDs will light. This tests the connections and that the tester is properly connected. Touch the brass probe end to the positive battery terminal and the green LED goes out,and the red led gets brighter.Touch the probe to the earth battery terminal and the red LED goes out,and the green LED gets brighter.





Headlight cricuit

                      Head light circuit

                                            Headlight Diagram

                                                           Components

                                                   Battery

Wire

Fuse

Relais ×2

Headlight bulbs ×2

Switch

                                                                    function  



The battery supplie the power.

Wires carry it through the Fuse the Relays to teminal 30.

The relays functions as a remote switch,the main current flowsfrom the battery to the use or headlight bulb .

It is activated by a low current coil that acts as a magnet to close the switch .

Terminal numbers are 85+86. Terminal 85 goes to a earth or ground source.

Terminal 86 supplies power through a switch to complete the circuit.

Component Terms and Unit Definition

Component                                             Terms

Conductor                                                         Material forming path for the flow of current

Insulator                                                            Material that will not readily conduct electricity

Negative charge                                                                           Electron

Semi-conductor                                                 Materials that act as conductors or insulators
                                                                  depending on temperature,physical or electrical conditions. 

Positive charge                                                                             Proton

Electron current flow                                           The flow of current from negative to positive

Conventional current flow                                    The flow of current from positive to negative

Watts                                                                                 Practical power unit

Unit                                                     Definition


Volt                                                        Practical unit of electromotive force and potential difference

Amp                                                                                     Unit of current

Ohm                                                                                     Unit of resistance

Watt                                                                                 Practical unit of power

Farad                                                                                  Unit of capacitance

Hertz                                                                                     Unit of current