Input Sensors and Actuators On Vehicle

Toyota 4A - FE engine
Voltage to the fuel injector: 14.49V

Supplay voltage is very important for injectors to have power to operate the injectors.

1.5 : If the voltage supplay is low at injectors it may effect open time and duration of injectors, and it will effect performance of the vehicle.

1.6 full circuit diagram of fuel injectors including power supplay , realy ,and ignition switch.
2.1: Refrence Voltage at TPS Sensor:

There are two types of TPS sensors, one is a switch and another potentiometer or linear resistor type. Linear resistor has got 5 volts reference voltage (supply voltage) and a variable resistor track inside and varies output voltage depending on variable resistor. When throttle closed resistance is high and output voltage low, but when its fully open resistance is low and output voltage is high. With this sensor ECU always know at what state is a throttle and can determine how much fuel to add and use emission systems and actuators when vehicle at light cruise. When reference voltage incorrect because high resistance in supply wires (corroded or not plugged in properly) or broken wire dameged inccorect testing this can cause ECU thing wrong and receved half open throttle signal when its wide open. This can effect on fuel economy, emissions and incorrect engine performance. Also ground wires can cause problems, good ground voltage drop reading is usually lower then 0.05 volts if they have a high resistance at ground because of loose connection or corroded wires the can create a high voltage drop at location of the problem and also effect output voltage to ECU from TPS esnsor. And finally ECU ground should be in good working order as it can effect our reference voltage to the sensors, not just TPS as most of the automotive sensors use 5 volts as a reference voltage. So its important when testing TPS to check first supply voltage or reference voltage and second good ground to the sensor. Also some TPS sensors have a fourth wire which can be an idle switch, this is when throttle closed and no air coming to the engine, so ECU know that it need to open idle control valve to keep engine running.
Other type is a switch, its only shows engine 3 modes, idle, light cruise and wide open throttle. Simple but still sensor. Not used on late model cars as less accurate.

2.3 ignition on
2.4 reading of meter; 4.95 Volts

Grond at TPS sensor:     3.3 Record of voltage engine start reading 0.2 volts

Throttle POsition Sensor return / otput:
4.2 record of reading in on ignition 0.55V

4.3: Halp throttle open meter recording is 2.005 Volts

4.4: Full open thrttle engine not runing only ignition on reading obout 3.8 volts.

4.5 Slowly open the throtttle from the closed position to the full open position , the meter resding is slowly increase we can in the next vidio

4.5 The four wires going to the TPS continue with these , the metre reading 0V when throtlle is closed, and 12- 14V when the throttle is opened

      closed throttle reading is about 3.3 mV

          fully open throttle meter reading is 13.31 volts.

4.91 Circiut diagrm of TPS
My all explainiton and answers of qutions No; 2.5 , 2.6, 3.3, and 3.4 are up under 2.1 refrence voltage.

5.2 Record wire colousrs and voltagebelow:

Idle wire : colur Black

Volts at idle ; 0.08V

Volts apart throttle or open throttle: 10.70 volts

Wide open thrttle wire colllur: Black

Volts at idle or part throttle: 10.24 volts

Volts at open throttle : 0.00V

Note: we tested the throttle position switch on Nissan OHC engine wich has all of three wires in black colours.

here picctures of TPS switch below.

          TPS swich output voltage @ Idle 0.08V

                   TPS switch volts at Idle or part throttle 10.24 volts



5.3 Circuit diagram of TPS switch.
This positon sensor is contact switch an ECU refrrence voltage to ground , this switching action cause the signal at the ECU to go low whenever the swith contact are closed. Reffirng to voltage IDL signal voltage is low when the throttle is closed and goes high when the throttle exceced about roougly 25 degree open. PSW voltage is high untel the throttle opens about 70 inch then goes low again.

ECT (Engine Coolant Temperature) Sensor
6.2 Engine ignition is On but not start

6.3 meter reading 3.59 volts , good connection
6.4 enine is normal operation temperature it was cold , and this was the right temperature of engine

6.6 In this pictuure reading of meter the engine is start and wrmed reading is 2.67 volts.
6.7; Awarmer engine usailly show lower voltage Yes we can see in cold engine i have got reading 3.59 volts and warmer engine 2.67 volts.

6.8 Discribe how an ECT sensor works

Engine coolant temperature sensor (ECTS) is located in the coolant passage of the cylinder head for detecting the engine coolant temperature. The ECTS uses thermistor whose resistance change with the temperature.The electrical resistance of the ECTS decreases as the temperature increases, and increases as the temperature decreases. The reference 5V of the ECM is supplied to the ECTS via resistor in the ECM. That is, the resistor in the ECM and the thermistor in the ECTS connected in series. When the resistance value in the thermistor in the ECTS change according to the engine coolant temperature, the output voltage also changes.

6.6 How the ECT sensor voltage affect the fuel injection output from the ECU'
The fuiel injector duration and control the ignatin also control the ignition timing using the information of engine coolant temperatureto avide the engine stalling and improvedriviblity.
6.10: If ECT sensor creat wrong it it should be send incorrect voltage to ECU . That cause engine runing wrong The ECU does not know how is the temperature of engine the big diffrency is fuel/air ratio should engine runing rich or lean . My experince it cold the engine hard to start after starting engine is missfirng.

7.0 Ground coolant temperature sensor

7.4 Strat engine recording voltage on meter is 35.6 mv ( good grond will usually read less than 0.05 v and some manufacture is say 0.10V ) in this experment i had good ground.
7.5 what does this voltage tell you about the ECu earth .
The ECU ground is importannt , ahigher than spacifaicaton reading will also be caused by poor gruond at ECU wich the ECT is depent on for proper operation.
7.4 what could go wrong so that the ECU earth is not good.
We can see in the diagram the ECT sensor ground connectet to ECU if the ground is not good the circuit is not complate there is only one refrence volatge nogrond the ECT sensor not working.

   Circuit ddiagram of ECT sensor and inside detail of ECU .

4.0 RPM Snsor Or Crank Positon Sensor (CKP):

4.5 I had set the multimeter on AC volts and try diffrent wire then i get the correct wich the AC readinge meter 4.75 AC volts.

4.6 Then i had increase engine RPM abuot 2500 rpm recording from the meter is 7.96 volts (wich is AC volt).

4.7 Then return the to Idle speed and switch the multimeter to DC volts . in this picture you can see 0.90 volts at idle

4.8 Then i had increase engine RPM to about 2500 rmp, i get 1.495 volts .

9.4 I witched the vo;tmeter to read Hz . I record the reading from the meter 653.6 Hz.



4.10 In this picture we can see incresed engine RPM to about 2500 rpm the meter reading is 2.088 KH and then returne the engine to idle.
Here is some readings of RPM sensor in AC volts, DC volts and Hertz.
We used magnetic pick up sensor and AC volts and Hertz showing better then DC volts that its working.
This type if RPM sensor is an AC generator, it produce AC voltage when rotating and the number tips on the shaft indicate on number cylinders in the engine. AC volt function of multimeter tells us how much voltage it generate for every tip passing the sensor magnetic pick up and a Hertz tells us how fast its rotating, as if speed of the shaft increased it increases frequency of rotation, so it start to rotate faster and get more revolutions per minute. Most of this sensor has got adjustable gap between tip and magnet, so if the gap is too big it wont generate signal or it could be weak and not enough to work properly, also they have a certain life and if not working, must be replace as non fixable item., if theECU did not recive the correct signal from the RPM or crnk sensor it cause faulty sensor, shorte or grond wire, or loose connection or faulty signal converter.
4.15 circuit diagram of RPM and Crank postion sensor below.

 MAP or MAF Sensoor:
5.6 I had turn on the engine and folow the instruction for getint in idle accliration .5.6 in this picture the reading the igntion is ON but engine not start multimeter reading is 1.83 Volts.
9.0 IAT (Intake Air Temperature), ACT (Air Charge Temperature), or MAT (Mainifold Air Temperature) Sensor.

9.3 I had set up the meter to read the DC volts and attach the red lead to pin and the black probo to the ground .

9.4 Recording the reading from multimeter 3.182 V , that is the good reading ,

9.5 Is the reading more or less than the readiinng you had ECT?
Less than ECT.
Does this show the IAT sensor is colder or hotter than th ECT sensor?
Hotter than ECT.
9.6 Discribe how the IAT sensor works.

The IAT sensor resistance changes in ressponse to the intake air temperature , the sensor resistance decrease as the surronding air temperature increases , this provides a signal to ECU, indicating the temperature of the incomig air change.

IAT is used to correct fuel quantity (puls width) since air temperature effects air desinty.

Properly functinig inttake Air Temperature (IAT) sensor shold exhibit the risistance valves indicate in this chart

9.9 Describe what could go wrong to create an incorrect IAT signal for the ECU.
Faulty IAT sensor, loose connection, bad ground, high risstance in the circuit or open the circiut.

9.10 Wiring diagram of IAT senor including incide ECU detail

5.7 The engine is start in Idle the reading of multimeter is 0.60 volts

5.8 After short acceleration of engine got the reading is 1.052 volts.

Desribtion:

Inside MAP sensor is a silicon chip which changes resistance with different pressure inside intake system and this changes output voltage to ECU. When engine at idle its almost no pressure inside intake (vacuum) so its gives low voltage output, but when throttle open, engine starts to accelerate and pistons suck more air inside, they create certain pressure under different engine loads and change output signal of MAP. This sensor tell ECU how much load on the engine and how much goes in so it can choose how much fuel to inject. Also inside map sensor is a Winston bridge with one constant resistor and one variable resistor (silicon chip). It could be a lot of things which can interrupt this sensor, such as vacuum leak from manifold (hole in gasket or rubber hose), also if silicon chip damaged it also will effect output voltage, wire connections of ground or reference voltage can be corroded or loose.

5.13 Circuit diagram of the MAP sensor .


10.2 In this expermint i had setting multimeter in diffrent setting (DC, AC volt, Hz, %Duty Cycle).
10.3 Recording meter of diffrent setting are below.
DC Volts 125.3 mv
AC Volts 1.270 Volts
Hz (hertz) 25.27 Hz10.0 Camshft Position Sensor (CMP)

% Duty Cycle 82.7%

                                           DC volts: 125.3 mvolts

                                          Hz : (hertz) 25.27 HZ

                                            % Duty Cycle: 82.7%
The CMP sensor provide the campshaft position information, called the CMP signal , wich is used by the power from (PCM) for fuel synchruoizte.

AC voltage will move between 0.3  - 1 AC voltage . The AC voltage whole time engine is cranking this is normal , if the sensor is bad the multimeter will not disssplay any  AC voltage.
AC voltage increases with engine RPM, so the faster the engine cranks , the higher the AC voltage.

The DC mode is that this signal should output the amount of voltage that comes into this sensor on the power circuit . If the CMP sensor bad we will get no reading .

                                
10.4 : circuit digram of Cam position Sensor.