Back-Probe Bench Test

 BACK-PROBINGWIRE BENCH TEST

Basically carefully taking a needle and sliding it between the wire and the connector so as to not damage the weather proofing until it contacts the metal part of the connection without piercing the insulation then using this as a place to take a voltage reading. 

  

Turn the multimeter on and put the setting to it would read Ohms (resistance)
O/L : is the result when the leads not in contact with each other ,O/L stands for over load which confirms that we have an open circuit and the resistance between the leads are too high for our multimeter to show hence O/L.

Obtaining Ohms reading with leads connected.
0.5 Ohms which tells us the internal reasistance of the Ohms meter and the leads... we need to take this resistance out of any resistance we measure with this meter so we could have an accurate reading .


I used a plug which had one side of the plug and the wire still attached so I back probed the plug and measured the resistance from the plug to the end of the wire which was 1 ohms
so 1. -0.4(internal resistance)= 0.5 ohms which is the correct resistance readings

Off-Car Practical 1

Off-CarPractical 1

Injector test

Note:The electronic fuel injector is no more than an electromagnet that lifts an armature connected to a nozzle and allows high pressure fuel to spray out into the inlet manifold in a fine atomised mist. Injectors from systems that use dropping resistors in the power feed to the injector can be identified from those that do not by their resistance value.

This picture show the injector at duty cycle as it pulse open and closed. As the injector open the switch On, and closed when it turn Off. This information is used to determine the injectors operation. Looking at On and Off time, and  measure the voltage


Common values:

With resistor                                  1.5 - 3.0

(Or with current control built into the E.C.U.)

Without resistor:                        14.0 - 17.0

Practical task sheet

Checking Injectors off a Vehicle

Injector	1	2	3	4
Manufacturers specification Ohms	13.8 Ohms	13.8 Ohms	13.8 Ohms	13.8 Ohms
Winding resistance Ohms	11Ohms	9Ohms	12Ohms	9Ohms
Earth leakage test	Y	Y	Y	Y

 Click Injector test

Injector  No:	1	2	3	4
Injector operation Audible. Yes / No	Yes	Yes	Yes	Yes

State any other engine problems that could give the same result as an injector not firing.

It will cause driveability problems like stumble, hesitation, backfire and surging.

Practical task sheet

Cleaning Injectors off a vehicle

When removing fuel injectors from the engine take care to:

Do not create sparks near fuel injectors and graduated cylinder. Keep fire extinguisher nearby in case something could go wrong.

Injector No:	1	2	3	4
condition	yes	yes	yes	yes
Ppray pattern	yes	yes	yes	yes
Flow rate	yes	yes	yes	yes
Leakage (dribble)	yes	yes	yes	yes

How many injectors require attention?

Non

Describe the condition of all the injectors that you tested.

At any faults components at this point, is to ensure all the fuel-injectors meet the specification standard and shown all the injectors test results are in good condition.These can identify by visual inspection and their bench test showing for any poor spray of any kind. Beside allthe injectors are clean and work perfectly.

Testing ignition Coils Method

 Coil Specifications

Coil# 1 No     IC-13                                      Coil #2 No C6R 500

Coil# 1 Voltage12volts                               Coil# 2 Voltage12volts

Coil #1 Primary 1.5 – 1.6ohms                 Coil #2 Primary6.5 – 8.5ohms

Coil# 1 Secondary6.0 – 7.0k ohms          Coil #2 Secondary6.5 – 8.5k ohms

Coil Test Results

Coil #1 Primary 000.3ohms                                              

Non Serviceable

Coil #1 Secondary06.8k ohms

Serviceable

Coil #1 Earth leakage test 0.00

Serviceable

Coil #2Primary 001.9ohms                                               

Non Serviceable

Coil #2 Secondary08.05k ohms

Serviceable

Coil #2 Earth leakage test0.00

Wasted Spark Coil Pack

Coil #1 Secondary 07.02k ohms                       

Coil #2 Secondary 07.02k ohms

Coil #1 Primary 0.9ohms

Coil #2 Primary 0.9ohms

Testing Ballast resistors

Specifications

Ballast resistor 1 NoBR1                

Ballast resistor No 1 ohm spec 0.9 – 1.6ohms

Ballast resistor No 2 ohm spec 1.5 – 1.7ohms

Ballast resistor 2 No BR3

Measured Resistance Values

Ballast resistor No1 measured  001.9ohms       

Not serviceable

Ballast resistor No 2 measured ohms 1.7ohms

Serviceable

 COIL

This is the Primary IC-13 and the spec of 1.5 to 1.6ohms also the current draw of 5.55amps from the measurements.

Calculation

V = (I, R)

V = 5.55 x 1.6

V = 3.33v

Current draw                                     5.55amps

Coil calculated Voltage Drop         3.33v 

Coil measured Voltage Drop         0.251v

BALLAST RESISTER

 Calculation

V = (I,R)

V = 5.6 x 1.7

V = 9.52v

Ballast resistor calculated voltage drop               9.52v

Ballast resistor measured voltage drop              10.93v

Did your calculated values equal your measured results explain why or why not?

The Ballast resistor reading and calculation match the specification but the coil did not meet the spec.

IGNITION 1(Function Generator)

 This picture show the spark firing using the voltage generator, as the switch turn slightly adjust  it's volume, current flow from the primary winding of the ignition coil via the igniter to earth. This create a magnetic field which surrounds the secondary winding of the ignition coil. As the primary current ceases, the magnetic field collapses rapidly through the secondary winding and generates a high voltage which is available to the spark plug through high tension leads.  

In this wiring diagram shows 12volt supply connect to the positive of the ignition coil and from the negative to the igniter to earth trigger.

This ignition wiring diagram show the voltage generator using to control currents to the spark plugs.

IGNITION 2 (Distributor)

This wiring diagram is trigger by the distributor. To work the spark plug the distributor is igniting by turning the motor manually and with the contact breaker close, this allow current  to the primary winding of the coil creates high voltage. when the magnetic field collapes in the secondary spark is create.

The distributor trigger type has a dwell angle this is the time length which the power transistor is turn on attach to the rotor teeth’s relate to the contact point and trigger spark plugs. 

IGNITION 3 (Using Wasted Spark)

Draw a wiring diagram of how you wired the circuit.

This diagram shows the waste spark distributor. Each coil is connected in series between spark plugs. The ignition is carried out twice at each coil and both spark plugs firing simultaneously. There are two separate series circuits in this type. Here I’m using two spark plugs in two separate circuits. 

 

IGNITION 4 (Coil Over Sparks Plug)

Draw a wiring diagram of how you wired the circuit

In this diagram we used a coil over ignition spark type. The circuit diagram indicate the coil is build up inside the unit and with no high tension lead used.

Off-Car Practical 2

 Off-CarPractical 2

Building a simplified ignition module

What difficulties did you encounter in building this circuit?

Finding the lowest possiblerange around 4.5ohms so the trigger can provide the current strongly to keep the circuit work and create good sparks in the secondary.

If you were going to build this circuit again what would you do differently?

It is necessary if this circuit can operate normally without resistors used and that depend on the type of trigger. One thing I would change is the resistance in the circuit. Goodadvance of the resistorcan create good sparks.

Sensors

TPS Throttle Position Sensor (potentiometer)

(It is critical that you follow the manufacturer’s set-up procedure) For example: 

The idle position is recognised by the lowest voltage reading through the sensor but in contrast, the maximum power signal is recognised by the highest reading at the full throttle position of the sensor travel.  

Checking the Throttle Position Sensor

What type of TPS is this?

Potentiometer type sensors

Internal operation and why your voltage changes

At closed throttle the IDLE contact is held closed. This pull the IDLE signal circuit to ground, as the throttle open the IDLE contact break causing the digital IDLE signal voltage to go from low to high.

The operation is when the throttle is closed the full resistance value of the potentiometer is in series with the ECU reference voltage. This causes a large drop in the computer reference voltage and a low voltage signal is given. At wide open throttle, only a small amount of potentiometer resistance is in series with the ECU reference voltage, which causes only a small drop in the computer reference voltage so a higher signal is given to the ECU. Between these extremes of closed throttle and wide open throttle the magnitude of the voltage signal to the ECU will be proportional to the throttle valve angle.

The ECU, by monitoring the TPS voltage signals, can determine the fuel delivery required from the throttle valve angle.

NOTE: Always use a 5V supply

Throttle angle(In Degree)	Voltage output
0c	0.322v
22.5c	1.13v
45c	1.45v
65.5c	2.613v
90c	3.651v

Graph

Throttle Position Switch

There is an idle position signal that is used mainly for fuel cut-off control and ignition timing corrections. The power signal is created at full throttle and is used for increasing fuel injection volume which in turn increases engine power output. Note there is no switching at part throttle.

Throttle position switch detects throttle position at idle or full throttle by using switch contacts that are connected or disconnected as throttle position changes.

This type of switch can have two or three contact positions and is usually checked and adjusted using a multi-meter. Adjustment is made by loosening the mounting screws and rotating the switch assembly.

On - Off type throttle position switches can have:

Two position (three pin) or

Three position (four pin).

Testing the throttle position switch

,

  

PSW means power switch (WOT)

- IDL means idle circuit

- E means earth

 Explain the internal operation of this sensor and why the resistance changes

As the IDE pass 1.5 degrees the IDE switch open this makes an open circuit at the IDE and when it gets to about 70 degrees it make the contact closed. This causes the change in the resistance.

Operation:  In the voltage, the IDL signal voltage is high when the throttle is closed and goes low when the throttle exceeds about 1.5 degrees opening. PSW voltage is low until the throttle exceeds about a 70 degrees opening, then it goes high.

MAP (Manifold Absolute Pressure)

On this graph i recorded different voltage readings according to different vacuum. It shows that the MAP sensor load line is straight and for every vacuum reading its a specified voltage

Inspection Power Output of Vacuum Sensor

Applied Vacuum	13.3 kPa 100 mmHg 3.94 in.Hg	26.7 kPa 200 mmHg 7.87 in.Hg	40 kPa 300 mmHg 11.81 in.Hg	53.5 kPa 400 mmHg 15.75 in.Hg	66.7 kPa 500 mmHg 19.69 in.Hg
Voltage Drop	0.3 – 0.5	0.7 – 0.9	1.1 – 1.3	1.5 – 1.7	1.9 – 2.1

 

Vacuum Gauge	Voltage
0	4.50v
10	3.40v
20	2.60v
30	2.26v
40	2.00v
50	1.60v
60	0.60v

Graph 

In this exacise the Vacuum's performance match the spec shows aboved.  

Does a map sensor read vacuum or pressure?

Vacuum

Explain the internal operation of this sensor and why the output voltage changes

The test is react to the vacuum gauge as it induces the voltage decrease showing in the graph above. What happen is the map sensor measures the intake air volume by monitoring changes in the gauge this is the load,inside of the sensor is the silicon chip, when pressure in the intake manifold changes, the silicon chip flexes, causing a change in its resistance. With varying resistance of the sensor causes a change in signal voltage at the Pressure intake manifold terminal.

MAF Air flow/mass sensors

S4/SB/RS4 MAF Mapping

What voltage did you get when you first powered up the sensor without passing air over the sensor 5volts.

How did the voltage change when air was passed over the sensor?

When air passes through the air flow meter, it forces the measuring plate open and the volume of air entering the engine increases, the movable contact moves across the fixed resistor, causing a change in signal output voltage and gave the signal information back to the ECU. This signal voltage is now changing depends on the volume of air entering.

Operation

As the intake air passes through the sensor, the angle of the air flap will change according to the volume and velocity of the intake air demanded by the engine. The value of the potentiometer resistance that is sensed by the electronic control unit will be in proportion to the angle of the air flap.

A Mass airflow normally uses an energised resistance wire to detect airflow

Vane or flap air flow sensor/meter (AFM)

VANE ANGLE (In Degree)	VOLTAGE
0c (close angle)	2.270v
22.5c	4.50v
45c	7.80v
65.5c	8.50v
90c	9.30v

 

Internal operation

The operation is reacting to the measuring plate. The voltage increases as the plate open. This cause by the resistor R2 connected in parallel with R1 allows the meter to continue to provide volts supply signal in the event that an open occur in the main potentiometer R1.