4848 ON CAR

                       SCAN TOOL DIAGNOSTICS

A scan tool is also known as OBD interface,code reader,or an OBD scanner.

OBD is a computer based system found on most vehicles,whose main job is to keep tabs on the emission levels.
Over the years,OBD systems grew more sophisticated,and today can provide access to hundreds of vehicle parameters.
Most cars today have an OBD 1 and 2 systems,and are therefore compatible with the scan tools.
A scan tool is a device used to access on board diagnostic information.Scan tools come in many shapes and sizes,different brands.But there are two basic types :Stand Alone and PC based.As the name suggests,stand alone scan tools do not require a computer.However,they typically have a small screen with a miniature interface,run only proprietary software with limited functionality,and cost significantly more then comparable PC based scan tools.

PC based scan tools harness the power and economy of scale of modern PC's,and have a number of important advantages:
*Large.easy-to-read screen
*Unlimited storage for data logging
*Wide selection of diagnostic software that can be easily updated.
*Remote data acquisition
*Cost a small fraction of the cost of comparable stand-alone scan tools.


PC based scan tools can:
*Turn OFF the check engine light,and erase stored diagnostic information
*Check emissions readiness
*Read and erase trouble codes (generic and manufactures-specific)
*Display real time parameters
*Record data for later playback.
*Plot data in the form of graphs and maps.
*Display customizable Digital Gauges.
*Serve as a dynamo meter.
*Provide a drag strip feature.
*Generate printable diagnostic reports.
*Access manufacturer's diagnostic reports.
*Do lots of other cool and useful things

Information from:ScanTool.net


Some cheap scanners are not able to read faults on new European cars.They are not compatible

Some countries have free scanning.They charge for the job and scan for free.One example is Korea


Recently i was working on a Mitsubishi Pajero diesel.It had the ABS light ON.We plugged in the scanner.There was no fault codes.Everything looked fine.But after 30 seconds the ABS light kept coming ON.The scanner showed no fault codes.
Then after driving the van the scanner picked up a fault.It faulted a speed sensor.
We did find the fault eventually.
The scan was being done when the van was parked on the ground.
When we inspected the van on the hoist,we found a lot of movement on the wheel hub.The van had faulty wheel bearings.That's why the scanner picked up a fault on the speed sensor.
Maybe there was too much play in the wheel bearing.
After 2 brand new wheel bearings on each hub,the ABS light was OFF.
The van drove really smooth.
This is an example on how a mechanical fault can cause a fault at a sensor and would cause 1 of the safety lights to turn ON.

                                                                           

                                                                   

 

                                                                                

                                                                              


....................................................................................................................................................................
Type of information   Letters to     Value of    Units for
(PID=Parameter         describe it        data           data
Identification)                E.g.TPS                           E.g.volts
.....................................................................................................................................................................
Engine Load                                           MAP                           2.58                    gm/s                  
(how much air comes in)
.....................................................................................................................................................................
Engine RPM                                            CRA                              667                    RPM
.....................................................................................................................................................................
Throttle angle                                        TPS                              10                       %
.....................................................................................................................................................................
Engine coolant                                       ECT                              75                       C
temperature
.....................................................................................................................................................................
Intake Air                                                 IAT                               20                       C
temperature
.....................................................................................................................................................................
Fuel Injection                                          FIP                              2.4                       ms
opening pulse
.....................................................................................................................................................................
Vehicle Speed                                          VSS                              0                          km/h
.....................................................................................................................................................................
Oxygen sensor(s)                                    o2                                0.52                    V
.....................................................................................................................................................................
Fuel Trim                                                   FT                                -2.3                       %
.....................................................................................................................................................................
Idle control                                                                                       ON
....................................................................................................................................................................
Air condition                                             AC
.....................................................................................................................................................................
Malfunction Indicator                                                                 ON
Light   (MIL)
.....................................................................................................................................................................




5.Find What Data Has Changed
   5.1  Look through the scan tool data to see what PIDs
           (Parameter Identification of system voltages) have changed.
           Which readings don't make sense or don't read what you would expect.
           Concentrate on the PIDs related to the codes:
   5.2  Record the PIDs that have changed below:
...................................................................................................................................
Type of information   Letters to     Value of   Units for
(PID=Parameter         describe it       data          data
  Identification)
...................................................................................................................................................................
Intake Air Temperature                          IAT                                                                       
....................................................................................................................................
Mass Air Flow                                               MAF                               0                          gm/s
.....................................................................................................................................
Short Term Fuel Trim                               STFT                            12.5                          %
...................................................................................................................................
Throttle Position                                         TPS                                0                              % 
..................................................................................................................................       



6. Visual Inspection to find fault
    6.1 Do a visual inspection under the hood to find where the problem is.Use information from the code to know where to look for the problem and what type of problem to look for.
Describe the problem you found:
* The TPS sensor was not plugged in



7.Repair fault
   7.1 Plug back in the connector,or repair problem found
   7.2 Describe what you did



8.Re-check Data PIDs
   8.1   Re-check the data with the scan tool
   8.2  Record the voltages for the PIDs related to the problem,to confirm  they are back to normal

...................................................................................................................................................................
Type of information   Letters to     Value of    Units for
(PID=Parameter         describe it        data            data
    identification)
....................................................................................................................................................................
Intake Air temperature                             IAT                               27                             C
.....................................................................................................................................................................
Mass Air flow sensor                                   MAF                              2.58                      gm/s
....................................................................................................................................................................
Short Term Fuel Trim                               STFT                           -2.3                          %
.....................................................................................................................................................................
Throttle Position                                          TPS                                 10                          %
.....................................................................................................................................................................
        


9.Clear codes
     Describe what you did to clear the codes:
     *Used the scan tool to erase the fault
     *Some codes get erased by itself.The ECU doesn't the fault anymore,so it clears   the code.



10.Re-check for codes and record codes in system now:
      *There are no fault codes in the system.The system is back to normal.




          WS4   Fuel Pressure and flow  (Petrol only)

Fuel is the means from which most of today's engines derive the energy to operate.But as the fuel deposits are being depleted,alternative fuel sources are being found.
Some alternatives are the electric hybrid cars,solar powered engines.
But petrol and diesel are the most widely used fuel today.Most commercial vehicles are diesel.
And most private passenger cars are petrol driven
Petrol engines are SI(Spark Ignition)
Diesel Engines are CI(Compression Ignition)
Most new vehicles use a electric fuel pump.The function of the fuel pump is to pump fuel at pressure to the injectors.The injectors are controlled by the the ECU.Each time the injectors open the fuel is sprayed into the combustion chamber at high pressure.
Some older cars used to have a mechanical fuel pump.The pump is mounted on the valve cover.And is operated by the cam lobes.These worked quite well.Till the EFI was introduced.And then came the electric pump.And then slowly as the technology improved,much powerful and compact electric pumps were designed to meet the high demands of the current modern engine.

MAKE:TOYOTA
ENGINE:4A-FE

These Toyota engines are very simple.
Very easy to identify the parts.
The parts are not expensive.
The engine is simple to work on.
They are good and reliable motors.
And very economical.

   Locate the two closest fire extinguishers.
   There were fire extinguishers mounted on the wall near the doors.On the right hand side of the doors.
And there were also signs and instructions on what to do in case of an emergency.
All the fire extinguishers had the valid stickers.

All the petrol engines that we worked on in the class were Toyota engines.That's the 4A-FE engines.Most of these engines had the manual with them.
We checked the Fuel Pressure Specification for this engine.
265-304kPa
C2.7-3.1 kgf/cm2
38-44 psi

Measure the fuel pressure with the key ON,engine OFF.
240 kPa

Idling:Measure the fuel pressure with the engine idling.Watch the pressure for a couple of minutes.
The pressure reading we got was 250 psi.

Maximum:With the engine idling,use the special tool to clamp the fuel return line.
This should only be done for a short period.
The reading we got was over 600 psi.

WOT:With the engine idling,disconnect and plug the vacuum line going to the fuel regulator
The pressure reading that we got was 310 kPa.

Residual:Turn OFF the engine,and watch the fuel pressure for five minutes.
The residual or the rest pressure we reading that we got was 270 kPa

Flow:Hook up proper equipment to read fuel volume.
Record flow gauge results of volume,or how much fuel pumped in 15 seconds.
Used a orange plastic clamp to block the fuel inlet hose.
Once the hose was blocked,we loosened and removed the hose clamp.
Once the clamp was removed,it was easier to remove the t hose.
We removed the inlet hose.And cranked the engine.
We managed to collect 690 ml of fuel in 15 seconds.
*(the results should be about 500 ml in 15 seconds)
This test result proves that this is a good fuel pump.It has normal pressure according to the manufactures specification.
*We put the fuel that we had collected back in the fuel tank.
*The petrol kept in an open container will give off harmful fumes.The fumes can cause headache and dizziness,which can cause a person to fall on a running engine and injury can be caused.

Replaced the fuel hose back.
Tightened the hose clamp.
It was tight.
Started the engine.Checked for any leaks.There was no leak.
There was no smell of petrol anywhere also.
The engine was running fine.

It is very important to know the vehicle fuel flow/pressure.
If the fuel pressure is low,the injectors will not get the required amount of fuel at the required pressure.
So instead of spraying pressurised fuel into the combustion chamber,there could just be drips of fuel.And this won't ignite in the normal pattern.
This could cause the engine to rough idle.
Also the engine will lack power.Especially on the motor ways when the engine requires more full because the vehicle is travelling at high speed.
The engine may start normally,but it won't run normal

Describe the symptoms a vehicle would give with each case:
Low fuel pressure:
The engine will not work normal.
It will lack power.
The engine may start easily.And it may idle normal.
But the real test is when the vehicle is being driven.As the vehicle is being accelerated,the need for more fuel increases.This is when the fuel pump is under load.And the fuel pump has to work hard to maintain the constant amount of fuel to the injectors.If the fuel pump is in the dying stage,then the vehicle would get sudden jerks.This is because the fuel pump cannot maintain a constant supply of fuel to the injectors.

Low fuel flow:
Low fuel flow is a sign of a blocked fuel filter.That's the first thing to check when you have low fuel flow.
Also there could be debris in the fuel line.
Maybe the container used to fill in the fuel in the fuel tank wasn't clean.And all the dirt and other rough particles could have gone in the fuel tank and blocking the fuel line.
Also there could be a dent or a puncture on the fuel line.This can happen if the vehicle drives over something big,or the vehicle is driven in quite deep puddles.


High fuel pressure:
If the fuel pressure is too high,it could damage the injectors.The original injectors on an engine is designed to handle a certain amount of pressure.And if the fuel pump was changed and the new fuel pump isn't of the manufacturer's specification,and is of a higher pressure value,then this could damage the injectors.
High fuel pressure is good for high performance engines.This is because the high performance engines require more fuel to burn at a much faster rate so it can go faster.But these engines also have high pressure injectors that can handle the high pressure fuel supplied by the fuel pump.

Faulty fuel pressure regulator:
There can be multiple issues with a faulty fuel pressure regulator.It could be open all the time.
Or it could be shut all the time.
Or it could have an intermittent issue,where it could just shut off while the vehicle is still being driven.
If it's shut all the time,then the car will not start at all.
If the fuel regulator is playing up,then the engine will have late starts.
The engine could just shut off while the vehicle is being driven.
The engine idle would play up.
The engine would stall all the time.

INPUT SENSORS AND ACTUATORS ON-VEHICLE

INPUT SENSORS AND ACTUATORS ON - VEHICLE
TOYOTA -- 1ZZ ENGINE (1ZZ-FE)





Two versions of the ZZ-series 1.8 liter in line 4-cylinder engine with dual overhead camshafts and 4 valves per cylinder has been used to replace the 3S series 2.0L (that was Japanese engine) and the 2.2L (that was an American engine) engines and were used in the Toyota Celica previous generation.The first type 1ZZ was first launched in the current U.S built Corolla,and now also used in the current Celica,and then adopted in the larger Japanese- market TOYOTA VISTA.
Here it is fitted with the VVT-i continuously variable intake-valve timing system given the FE suffix.
The 1 ZZ produces 107 kW(145 hp) at 6400 rpm on a 170 N.m(125 lb.ft) torque at 4200 rpm 10.0:1 compression ratio with regular-grade unleaded gasoline.The 2ZZ-FE is a new generation engine used in the Celica GT-S and is equipped with a two stage variable lift/timing system,called VVT-L om both intake and exhaust sides,combined with the VVT-i continuously variable intake valve timing.The 2ZZ-FE puts out 140 kW (190bhp) at 7600 rpm and 180 N.m(133 lb.ft) at 6800 rpm on a raised 11.5:1 CR with premium unleaded fuel.The two engines share the common bore pitch of 87.5 mm(3.44 in),but have slightly different construction of the block,and the dimensions of the cylinder.The 1ZZ-FE's aluminium block has a cast-in gray liners,which are 2.0mm(0.08in) thick,leaving 8.5 mm(0.33in) of metal between the cylinders.The engine has a long stroke of 91.5 mm(3.6in) relative to the 79 mm(3.11in) bore,obtaining a total displacement of 1794cm3.
Measuring 639mm(25.2 in) long,586mm(23.1 in) wide,and 632 mm(24.9 in) tall,the 1 ZZ-FE is about 25mm (1 in) shorter than Toyota's own 4A 1.6 L unit.It has a mass of 102 kg (225 lb)
The camshafts are chain driven on these engines.
A bolt-on TRD supercharger kit is available on the 2003-2004 Corolla,Matrix and Vibe.

<< Information from:Spyderchat.Com>>

The 1ZZ-FE engine has been developed around the following concepts with the following targets:

1. To enhance potential for cleaner exhaust emissions and better fuel economy by optimising basic specifications
2. To improve engine performance and to make its body even more compact and light weight by re-examining each engine component

(a)High performance -Aiming for ease-of handling,keep maximum output and torque at the top of its class,while attaining flat torque characteristics
(b)Lighter in weight-Build the lightest engine among those employing aluminium engine blocks
(c)More compact
(d)Emission regulation compliance
(e)Vibration and noise
(f)Parts reduction
<<Information from:en.wikipedia.org/wiki/Toyota-ZZ-engine>>






*The 1ZZ-FE engine combined substantially more power and economy with cleaner burning of fuel
*Low carbon emission






Working on the engine
The engine we worked on in the workshop was not a diesel engine.
We worked on a petrol Toyota engine--1ZZ-FE






The engine had a battery isolator switch
Had to turn the isolator switch ON to get the power from the battery to the ignition switch
Once the isolator switch was ON,we were able to operate the engine from the ignition switch
The engine was tip-start
Started at the first crank
There was a temperature gauge on the frame
There was a pressure gauge on the frame

 The engine mounted on the frame.Can see the gauges and lights

There were 3 other lights
One would be the engine oil pressure light,one for the check engine light,and maybe one for the alternator charge light.
Not 100% sure of the lights,as there was nothing written at each individual light






*This was a chain driven engine,and not a cam-belt type






It was running really smooth
Very well tuned Toyota engine
All the sensors and major components were on the top and clearly visible
The engine cover was not fitted,as it would have to be removed to access the injectors and other sensors
The only sensor that wasn't visible from the top was the crank angle sensor.
That's at the bottom.Near the crank pulley






The first test we did was on the 4 injectors
*A fuel injector is an actuator.

                                                                  The fuel rail and injectors

The fuel injector in a modern engine is the main actuator in the fuel system.All the fuel supplied for combustion,that takes place in the engine is the responsibility of the the injectors.The injectors job is to very accurately measure and deliver the precise fuel and air mixture in the intake runners.The correct fuel flow and spray pattern can only be achieved by an injector that has been well maintained over a certain time.
In most of the new cars and the modern OBD 2 systems,injectors are very closely linked with the misfire code problems






There are many reasons why an injector could cause a misfire code:

• A shorted out injector coil will draw a lot of current
• A bad injector ECM will cut the signals to the injectors
• Overheating problems can cause misfiring
• Clogged injectors will also cause misfiring
• In some cases like a overheating problem,the problem is not the injector itself,but some other conditions that cause the injector not to pulse,which then causes a misfire

*Most of the injectors are ground controlled
*One wire has battery voltage(Ign+,12.8-14.6v) and the other wire is grounded by pulse signals by the ECU.
*This is the negative trigger type.






*Some vehicles have positive trigger.(Some European vehicles).
*In these vehicles,the ECU supplies positive in pulses to the injector.






We located the 4 injectors.They were right on top.Were very easy to locate.






Traced the injector wires.And inserted a pin down the rubber insulation.Pushed the pin far enough in the plug to connect with the metal wire terminal on the inside of the plug.
We made sure there was no puncture or damage done to the wiring.

Picture of an injector.Shows the positive terminal and trigger terminals
Picture from:Toyota Forum




*The multimeter we used was borrowed from the workshop.






The RED lead of the multimeter was connected to the pin we inserted in the plug.
The BLACK lead of the multimeter was connected to earth(-) or grounded.






Made sure everything was clear of the moving parts,and started the car.
Recorded the voltage to each injector.

1. INJECTOR 1: 14.18Volts
2. INJECTOR 2: 14.18Volts
3. INJECTOR 3: 14.17Volts
4. INJECTOR 4: 14.17Volts

We checked the supply voltage to the fuel injectors to make sure there was a proper voltage supply to the injectors.If there isn't enough power supplied to the injectors,then the injectors wouldn't be operating at 100%.
If we had found a lower voltage at the injectors,that would mean that the injector circuit has a fault in it.There is a voltage drop (VD).This problem could arise from poor earth connections,too much heat,loose connections,fluid in the connectors,broken or perished wires,a fault in the ECU.
There could also be a problem with the alternator,which is not charging.And using the battery power to operate the sensors and other equipment.As the battery voltage goes down,the supply voltage to all the sensors will drop
If the supply voltage is low,the injectors will not operate well,to their 100% capacity.This might cause the vehicle to idle low,slow acceleration,loss of power,or may even stall.
The engine also wouldn't sound right

If the alternator is good,charging rate is normal,battery is good,battery connections are good,then that means the supply voltage is good.Then that eliminates the power source issues.Then have to check the wires,connectors
A short circuit in a component can also cause problems,because the short will draw too much current.




<<<The second sensor we tested was the TPS sensor>>>>>>
Located the Throttle Position sensor.
We were trying to locate the TPS Reference voltage.
There was 3 wires on the TPS.
Tried all 3 wires.Checked the voltages using the pin in the plug.Finally got the right wire.
The supply voltage i got was 4.98Volts




The purpose of the reference voltage to the Throttle Position sensor is to have a constant voltage supply to the sensor.If the Throttle is closed,or fully opened(WOT),or opening and closing,the reference voltage remains the same.The power supply to the TPS is normally at Ignition.


Q.What could cause problems so that there is not the correct reference voltage at the throttle position sensor?
A.*The Throttle Position sensor may not be mounted properly.
*The Throttle Position sensor could be faulty.
*The computer(PCM) could be damaged.
*There could be a short in the TPS circuit.Could be a short to ground or a short to another wire.




These problems can be fixed by checking for faults at the TPS,checking the TPS wiring connector,or maybe a break in the wiring.
*If the reference voltage is not correct,then the signal sent out by the sensor will not be correct and according to the manufacturers specifications.
*The engine will be running on a Lean air/fuel ratio.
*The engine will have loss of power.
*There will be an increase in emissions.




We then measured the Ground at the TPS sensor
We achieved this by testing the voltage output on all the wires.
                                          

  

 Testing the throttle Position sensor

        We were inserting the pin in the plug and testing the voltage

                                        Using the pin so the wires do not get damaged

Then we located the ground(-) or the earth wire at the TPS sensor

Slided the pin down the rubber insulation to the metal terminal.

The multimeter red lead was connected to the pin we inserted in the wire

The multimeter black lead was connected to ground(-)

Then started the engine

*The voltage we recorded on the multimeter was 0.031 volts.

(A good ground will usually read less than 0.05V.Some manufacturers say 0.10V)

Q.What does this voltage tell you about the ECU earth or ground?Why is it important to measure it?

The voltage we measured at the TPS sensor ground was 0.031volts.This is a very low voltage,near zero.There is a very low or basically no voltage drop.The ECU has a good earth connection.

A good TPS sensor with good earth and a good reference voltage should work perfectly

A lot of problems can arise from a poor earth or ground connection to the ECU.

*Normally to make sure there is always a good earth supply to the ECU,the manufacturers mount the ECU on 3-4 #10 bolts.

Some very common causes of bad earth are:

*There can be a bad ground connection from a lot of engine vibration.

*Also big sound systems are not good for the ECU.That's why it is recommended not to have the amplifier mounted on the sub-woofer box,as the vibration can cause damage to the electronic components inside it.

*There can be corrosion on the chassis of the vehicle where the earth wire is mounted .

*Could have loose connection at the battery.

Also there could be ground at only one place from battery.It's best to have ground from battery to chassis and also to engine.

*A lot of heat from engine.

*Moisture--from washing the vehicle,water blasting.

Most vehicles are grounded at the body(chassis).

The most important reason for this is that it halves the wiring to the components.It simplifies the wiring.And is very cost effective.

Poor grounds cause voltage drop.

The voltage drop can cause malfunction in circuits.

The sensor readings can be affected.

The bad earth connections can cause poor performance in almost any circuit.

One very common sign of a bad earth connection are dim head lights.

Also the blower motor will go slower.

When the brake pedal is pressed.the dash lights will be on.Very dim.

And other unexpected weird issues will come up.

The Throttle Position sensor on this engine is a Potentiometer

Picture of the TPS sensor

Disconnected the sensor plug to test the voltage at the wires

We tested the TPS sensor output(signal) wire.

The red lead was connected to the TPS plug wire.

The black lead was connected to the ground(-).

Turned the IGNITION ON.Didn't start the engine.

Tested the power output from the signal wire.Got a reading of  0.6 volts.

The wiring colour codes:Yellow=Input(reference voltage)

                                           Green=Output(signal)

                                           Brown=Earth(-)

Opened the throttle to about half way.Got a reading of 2.81Volts.The reading fluctuates as the throttle is moved.

Fully opened the throttle.(WOT).Got a reading of 3.89 Volts.The output voltage stopped at this value.But the voltage dropped as the throttle was closed.

As the throttle was slowly opened and closed,the output voltage slowly went up and down.

The reading was fluent.There were no sudden jumps or gaps.

How the Throttle Position sensor works

The Throttle Position Sensor we tested had 3 wires.A 5 volt power is supplied to the Throttle Position sensor from the VC terminal of the ECM.The Throttle Position sensor signal is supplied to the VTA terminal.A ground(-) wire is connected from the Throttle Position sensor to the E2 terminal of the ECM.This completes the circuit.

At Idle,the output voltage from the signal wire is approximately 0.6 Volts to 0.9 Volts.

When the ECM receives this signal voltage,it is able to know that the throttle plate(the butterfly) is closed.

As the accelerator pedal is pressed,the throttle opens more.When the throttle is approximately opened at half position,the voltage output at the signal wire is about 2.6volts.As the throttle is opened,the signal voltage increases.And as the accelerator pedal is released,the supply voltage decreases.This change in voltages from the signal wire to the ECM helps the ECM know the throttle butterfly position.And then the ECM makes adjustments required.It then decides how much fuel to supply to the injectors

Inside the Throttle Position sensor is a resistor and a wiper arm.The arm is always contacting the resistor.At the point of contact,the available voltage is the signal output voltage.This indicates the position of the throttle valve.At idle,the resistance between the VC or VCC terminal and the VTA terminal is high.And the voltage available at the signal wire is approximately 0.6volts-0.9volts.

As the contact arm moves closer to the VC terminal-(that's the reference voltage or the supply voltage),the resistance decreases and the voltage signal increases.  

When the throttle is fully opened(Wide Open Throttle -WOT),the signal voltage is approximately 3.5volts-4.7volts. 

Problems that could occur to prevent the TPS from sending the correct voltage to the ECU

• Bad grounding
• A malfunctioning TPS
• Bad connection 
• Broken or damaged wires
• Oil or debris in the throttle body
• A broken or wrong accelerator cable

<<ECT(Engine Coolant Temperature)Sensor>>

The Engine Coolant Temperature Sensor is an Analogue sensor.It measures the temperature of the coolant and feeds the data to the on-board computer.

This allows the ECU to determine when the engine is warming up and when it has reached it's proper and normal operating temperature.

The late model engines have engine coolant temperature sensors and use thermistors.

A thermistor is a device which provides higher control over the engine performance throughout the range of engine operations.A thermistor is a variable resistor made of solid state materials that changes according to the temperature.This type of thermistors have a negative temperature coefficient(NTC).This means that the resistance decreases as the temperature increases.

A close look at the MAF sensor

                                                  
                                                         Picture of the MAF sensor

                                                       Picture of the Cam Shaft Sensor(CMP)

                                                                                     

         Picture of a MAP sensor    

                               

 Picture of  a Toyota MAP sensor The part number is written on it

<<CHART OF INPUTS AND OUTPUTS>>

............................................................................................................

Coolant Temperature                                  Cold engine                            Warmed-up engine  
(THW or ECT)                                              2.292Volts                                     1.055Volts
DC volts
.....................................................................................................................................................................
Throttle Position Sensor                              Closed throttle                         Open throttle
DC volts                                                             0.559Volts                                 3.91Volts  
......................................................................................................................................................................
Crank or RPM sensor                                    Idle rpm                                    2500 RPM
AC volts and Hertz                                        2.561 VAC                                    5 VAC        
                      
......................................................................................................................................................................
MAP sensor                                                     Idle vacuum               No vacuum or key ON,engine OFF
DC volts                                                             0.512Volts                                      1.829Volts
......................................................................................................................................................................
Air Temperature                                             Cold engine                               Warmed-up engine
(THA or IAT)                                                    3.49Volts                                         2.256Volts
DC volts
........................................................................................................................................................................
Throttle Position Switch                                  
(Idle and/or WOT)
DC volts
.........................................................................................................................................................................
CAM sensor                                                         Idle rpm                                        2500 rpm
AC volts & Hertz                                                 0.702VAC                                    2.239VAC


.........................................................................................................................................................................
Fuel Injector                                                           Idle                                            Acceleration 
Duty cycle%                                                           0.2%                                                39.7%
.........................................................................................................................................................................
Idle Air Control                                                      Idle                                     Cranking or 2500 rpm
Duty cycle%                                                           30.9%                                               31.7% 
...........................................................................................................................................................................
Name
Measurement setting
...........................................................................................................................................................................

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
           
           WS1    Petrol Fuel Injector Testing


2.Check the voltage to the injectors when idling or Key On.This makes sure you have battery voltage to the injectors so they can work .The battery voltage we recorded was 14.16Volts.
Recorded the voltage at each injector by back probing.Be careful not to puncture or damage the wiring


Cyl#1                               Cyl#2                              Cyl#3                        Cyl#4
14.11volts                      14.12volts                        14.11volts                14.11volts


3.With the engine idling,watch injector firing by using an LED tester or test light(with normal incandescent bulb).Hook up test light and connect tip to pin that has back probed connector to injector.As the injector is grounded by the ECM to fire,the test light should also be grounded to fire,and will flash.


Cyl#1                              Cyl#2                              Cyl#3                            Cyl#4




4.With engine idling,watch injector firing by using a multi-meter set to read %(duty cycle).Record the readings for each cylinder at idle in the boxes below.


Cyl#1                              Cyl#2                              Cyl#3                              Cyl#4
98.9%                             99.0%                              99.1%                            99.1%                Duty cycle%
1.1%                               1%                                    0.9%                               0.9%


5.With the multi-meter still set to read % (duty cycle),accelerate the engine with short,fast throttle openings(don't over rev or damage the engine),and note in the boxes below the maximum % reading you can get on the multi-meter:note the RPM


Cyl#1                              Cyl#2                              Cyl#3                             Cyl#4
94.9%                             90.4%                             93.7%                            92.1%                   Duty cycle%
@2500rpm                    @2500rpm                      @2500rpm                    @2500rpm 
5.1%                                9.6%                               6.3%                              7.9%  


6.Set the multi-meter to read Hz,and with the engine idling,record the readings for each cylinder in the boxes below:


Cyl#1                               Cyl#2                              Cyl#3                             Cyl#4  
7 Hz                                  7 Hz                                7 Hz                               7 Hz                        << Hz>>


7.With the multi-meter still set to read Hz,increase the engine RPM(don't damage the engine).and watch how the Hz changes.Record your highest reading in the boxes below.Take the readings at the same RPM as you used in question 5.


Cyl#1                               Cyl#2                              Cyl#3                              Cyl#4
15 Hz                               15 Hz                             15 Hz                               13 Hz                       <<Hz>>


Pulse width ms=(% Duty cycle x 100)/Frequency
Using this formula calculate the pulse width of each injector both at idle and when the engine is revved up.
Show your calculations.

calculation for cylinder #1:                                             calculation (revved up)

(1.1x100)/7                                                                        (5.1x100)/15

=15.71ms                                                                            =34ms

calculation for cylinder #2:                                             calculation (revved up)

(1.0x100)/7                                                                        (9.6x100)/15

=14.28ms                                                                            =64ms

calculation for cylinder #3:                                             calculation (revved up)

(0.9x100)/7                                                                        (6.3x100)/15

=12.86ms                                                                            =42ms

calculation for cylinder #4:                                             calculation (revved up)

(0.9x100)/7                                                                        (7.9x100)/15

=12.86ms                                                                            =52.67ms

Cyl#1                            Cyl#2                           Cyl#3                          Cyl#4

15.71                             14.28                           12.86                           12.86          Calculated Time at Idle.

Cyl#1                          Cyl#2                          Cyl#3                        Cyl#4

34                                64                               42                              52.67         Calculated Time when revved.

Give your conclusion on whether this is an acceptable way to test injectors and why?

When the duty cycle and the frequency of injection increases,according to the increasing rpm,the injection time is longer for more fuel injection to the combustion chamber.