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.
The 1ZZ-FE engine has been developed around the following concepts with the following targets:
(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
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:
*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.
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
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.
Picture of the MAF sensor
Picture of the Cam Shaft Sensor(CMP)
(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.
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:
- To enhance potential for cleaner exhaust emissions and better fuel economy by optimising basic specifications
- To improve engine performance and to make its body even more compact and light weight by re-examining each engine component
(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 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
*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 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.
- INJECTOR 1: 14.18Volts
- INJECTOR 2: 14.18Volts
- INJECTOR 3: 14.17Volts
- INJECTOR 4: 14.17Volts
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 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.
