ws8 primary and secondary patterns

ws8

This graph show A as the dwell time, B as the firing voltage, C is the burn time

dwell time : 22

firing voltage:200+v

burn time :0.4ms

burn voltage 50v

This graph shows
burn time :16.1ms

firing voltage:19kv

ws7 exhaust gas analysis

ws7



co= 1.039, hc=150, co2=14.30,02=0.82%

engine is coldansd at idle , and warming up runs rich which creates high hydro carbons and a high co2 level

As the engine increases its speed and runs at a higher RPM hc and co2 levels drop and oxygen levels increase

ws6 o2 sensor

Oxygen sensors

Oxygen sensor located on the vehicle mazda capella 96 ( jonos car )

a zirconia switching sensor, has four terminal wires

This graph indiacates the oxygen pattern for the engine which is at idle giving us a lean and rich reading.

highest voltage reading 0.082v
lowest voltage 0.01v

average voltage .4v

cross counts 10

This graph shows us that the sensor has gone rich by the acceleration and voltage climbing to 0.98v
with only 6 cross counts

This graph shows us it is running lean, deccelerating flow of air as the engine is slowing down voltage of 0.1 774v

and deccelerating

ws5 scan tool

Scan tool

vehicle mazda capella 98

recored new faults

scan tool diagnosed vehicle showing fault codes p0100, p0110, p0505
3 faults were found

p0100 fault was a MAF sensor malfunction

p0110 was a fault to do with IAT sensor malfunction

p0505 was a idle control malfunction

all three were sensor connector faults

scan tools are one of the most important tools for the workshop, as it diagnose the engines computer, searches for faults and codes them so it makes a autoelectrians job really helpful.

ws4 Fuel pressure and flow

Fuel pressure

Safety is important when handling open fuel, good to know where the site fire extinguishers are

vehicle Toyota

specs for vehicle fuel pressure:

265-304 kpa(2.7-3.1kgf/cm2, 38-44psi

Check fuel lines for any leaks

When testing fuel pressure remove fuel pump fuse crank engine, pressure should now be relieved, safe to work on.

record fuel pressure by having the pressure gauge set and connected properly

with engine turn to "ON" only

reading was 200kpa

engine turn on and running at idle 250kpa

engine at WOT 300kpa

Symptoms

Low fuel pressure:

the vehicle would have idle problems, stalling at idle

High fuel pressure:

excess fuel is being sparyed through the injectors into the engine running at a rich level

Low fuel flow :

the engine would run lean not injecting enough fuel into cylinders

ws2 flash codes

Flash codes

Take note:

Depening on the vehicle make and model, the Ecu could be located in different locations.

having the ignition set to "ON", on the back of the ECU
turning the dign ostic selector fully clockwise wait two seconds, completly rotating the selector anti clockwise now. ECU should now be dignosing faults indicated by a flashing light located in the vehicles dashboard (may be a light on some ECUs depening on make and model),

the number of slow flashes indicates the first number to code, the faster flashes will tell us the second number to the code .

For instense slow one flash fast two flashes gives a 12 fault codestopping the flash fault code off simply the same way you turned the dignostic selector, turn it clockwise right round, have a two second gap and turn it anticlockwise, when turn the flash fault off u needed to do this twice

depending on your vehicle make and model this could be different use your vehcile manul to find flash fault vehicle used was a nissen sentrs

faults found:

code 31 MAP connector to sensor was removed

code 41 TPS connector to sensor was removed

code 12

is the fault of the ignition system, problems with ignition where that the contact points in the distributor were to far away from each other not making proper contact to fire the injectors .

Finding the fault and repairing it is important, once fixed do a systems check to ensure fault was removed from the ECU.

if there are no faults check light should stay on til system is reset.

ws1 petrol fuel injection test.

WS1

Warning when dealing with injectors, As petrol engine injectors can give a 15v shock, diesel engines have a bigger voltage.
Using a stethoscope, or long flat head screwdriver place it on the injectors, if the injectors are operating correctly a fant clicking nosie should be heard, yhis clicking indicates that the injector is opening .

Voltage off each injector

battery voltage :13.6v

back probe each injector taking the voltage reading with the multi meter connected to pin which has been back probed...

With each injector still being back probed connect a test light to each pin, having the engine at idle, check that each light lights up as the injector opens.

Recording the duty cycle % while at idle

reading in hertz engine at idle hz

Back Probing on bench

Obtaining a multi meter set on resistance

asuring the meter works touching both leads, meter should have a inf. reading

Note:

When dealing with back probing the main aim is not to damage any connectors, terminals and wires.

Having both leads touching the reading should be 0.0 as there is no resistance in the leads,

the reading on this meter reads 0.3 ohms meaning this is the amount of resistance in the leads of the meter.

Back probing a shell connector with attached terminals, gently placing a back probing pin down the inside of the insulation . reading 1.3 ohms - 0.3 = 1 ohm shows the amount of resistance in the terminals

Sensor ECT engine coolant temp.

ECT

With the ignition switched to "ON" back probing the ECT sensor with a mutli meter on volts while the engine was cold i got a reading of 4v, 5 after letting the engine run for minutes having taken anouther reading of 0.025v

This shows how the colder the engine is the higher the voltage output will be... Around 0.01v the engine temp. is at a perfect operating temp. around 115*c (220 F)

ECM also relays on the temperature of the engine coolant to determine if the engine is at operating temerature, the voltage changes due to the temperature being colder or hotter,

cold coolant indicated by less than 0.4 hot coolant the voltage sits around 4-5v good operating temp.

Sensors MAP

Manifold absolute pressure

The map sensor reads the amount of pressure against vacuum, creating a balance between the air/fuel ratio, ensuring a safe and smooth idle, accelerate and decceleration

3 wire map :

5v input, earth wire, signal wire

The signal wire sends a voltage related signal to the engines ECU which calculates; in relation to the TPS, how much fuel to inject into the cylinders.

vacuum is high when at idle or the engine is deccelerating as the throttle will be closed so the map will give a low voltage reading, but when the engine is at wot or accelerating the voltage reading is high as the vacuum decreases and pressure increased.

ignition coil

Ignition coil

testing the windings in both primary and secondary windings













picture
al-jazirah.com.sa

NOTE: completing the test i found that the cic31 ignition coil failed spec, best advice is to throw the component away.

Ci2500 ignition coil has good resistance to spec showing good continuity through the windings, both primary and secondary, this shows a good working, serviceable coil

wasted coil spark
having tested the Ci2500 for wasted spark, i only found results for the secondary windings, this could be, because the coil is either incoperated with a ignition module or off a four stroke engine.
coil readings:
no.1: 7.1 k ohms
no.2: 7 k ohms
theses readings sh0w a seviceable resistance

Sensors tps

Throttle Position Sensor

note:
potentiometer have a sliding variable resistor
that slides moving the throttle butterfly
Using a switch type TPS, having a 5volt supply conected right and earthed varible resistor should operate from 0 to 90 degrees, as the throttle is opened letting more air in, the voltage is increased ...

Note: round type sensors indicate that is a lener tps, switch type sensors are square in shape .

The varible resistor located in the tps unit, which sits on a number of sliding contact plates which are changed when the throttle increases and decreases from idle to wot (wide open throttle ), the more the throttle is opened the higher the voltage will be... 0.5v at idle - 4.02v at wot

Back probing a tps

having the voltmeter set to dc volts, and having a pin inserted down insulation, with the ignition turned to "On", i got a reading of 0 volts
Withe the engine still in the "ON' position, move the throttle to a half open position getting a reading of 2.52 volts
With the throttle at wot (wide open throttle) the voltage there was 5 .12volts

TPS operates with a input voltage of 5 volts, normally a grey wire. A signal wire to the ECU, somtimes a fourth wire to ensure that the signal to the ECU is a correct reading. As the valve angle changes due to the driver acclerating or decclerating, the ECU calulates and determines how much fuel is needed to deliver a good air/fuel ratio to maximize engine performance.

Throttle position switch

As before back probe the TPS

only having the ignition in the "ON" position, using a mutli meteri found which wires changed at idle and wot, the colour of the idle wire was Blue, the wot wire was Green

idle ranged from : 0.7 to 1v

wot ranged from :4.3 to 5 v

part throtle ranged from :2.5 to 3.8v