on car ilyas

WS5 Scan Tool Diagnostics

Warning: Be careful working around engines and exercise caution to avoid injury.
1. Scan Tool Data
1.1 Find a vehicle which is appropriate for the scan tool.
1.2 Connect the scanner, power it on, follow the instructions andinput the correct vehicle information it asks for so you can view the data.

Type of information (PID = Parameter Identification)	Letters to describe it E.g. TPS	Value of data	Units for data E.g. volts
Engine Load (how much air comes in)	AS	1.30	V
Engine RPM	E.S	762	rpm
Throttle angle	TPS	0.48	V
Engine coolant temperature	ECT	69	c'
Intake air temperature	IAT	49	C'
Fuel Injection opening pulse	injection time	2.8	ms
Transmission select position
Vehicle Speed		0	KM
Oxygen sensor(s)	O2	0.45	V
Fuel Trim
Idle control		69	%
Power steering condition
Air conditioning condition	AC signal	off	switch on/off
Exhaust Gas Recirculation (EGR)
Fuel Evap or Purge condition
Malfunction Indicator Light (MIL)
Barometric Pressure
Battaery		14.1	V

Trouble Codes or Fault Codes
2.1 Find where the Codes are listed
2.2 Record any codes, and what system and condition they describe in the chart below (Example: might be code number 21, for Throttle Position Sensor, signal voltage too low) If
there are no codes listed, put “none”.

System was normal and there was no faults and the car was also running fine by knowing this i went to the the scan tool and went to this screen where it is tells you how the car is and it shows you if there is faults or not and if does have faults it will come up with trouble code but with our case there was no codes whats so ever.

Lecturer put in Fault
3.1 Find your lecturer and have him create a fault under the hood (don’t look)

Record New Codes
4.1 Look up the codes now in the scan tool
4.2 Record the codes in the chart below. Also record what system is affected, and what condition is described.


when we checked through the scan tool i we came up with 2 problems in scan tool data but when i check for the codes we did not come up with any troubles i dont know why this happen we were meant to have trouble codes but we didnt. even tho this was checked the tauter and he didnt get it as well so the way we found the problem was we look at the data we got from before and then compared it and we got the TPS senor and Air flow sensor by knowing this we notice that voltage was very high for TPS and the engine was running rough and i think it was not idling well and it was reving high and low .

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:

Well we looked at the data sheet and notice that the throttle position sensor voltage was very high which was 5.10 V but when its normal you should be getting around 0.48V well thats what i got when it was normal and also i notice that the engine was not idling well so we notice that air flow sensor wasn't connected so the engine was running rough you could feel it and also hear it .


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 problem you found:

When opened up the hood i all ready knew what i had to look for because of the scan tool data so i found out that the Throttle position sensor was disconnected and also the Air flow sensor was disconnected so we this not been connected engine wasn't idling well and also engine was running rough .

So the way i had to repair the faults was i just had to plug back in the sensors i turned off the engine but the ignition on then i went on the scan tool to clear out the faults and then i went to check it if it was cleared it was and the system was back to normal.

i also checked the data sheet if the voltage was back to normal and it was .And other ways of removing the faults codes or other light on your dash board you can remove the battery terminals for 30 seconds and you can also remove the main engine fuse to get ride of the fault codes.

The importance of live data fault finding is that its pretty easy to know whats going on your car for example when you driving you can see how your car is running and if there is a problem you can see it and then you would know where the problem is makes easier. the parameters live data tells us because its for the intake the engine load and how much air is coming in .

Scan tool is very handy to use now it makes the job very easy and its very useful for every shop to have one be makes job easier faster and everything can be done very quickly .Scan tool tells where the problem could be and it gives you hint where to look but its 100 % accurate but like i said makes the job easier and its very handy to use .


WS7 Exhaust Gas Analysis (Petrol only)

1. With the analyser probe sensing normal air, what are the Four Gas readings? Record the amount and then what it means:

CO: 0.00 Means: you have a rich condition and you dont have enough O2 to create CO2 this mean co2

HC:12ppm Means: Hc is unburnt petrol higher content indicates a misfire or cold start.

Co2:0.00% Means: efficiency should be about 15%

o2:20.94% means: Rich means lower o2 level however o2 means lean mixture More 02 mean lean mixture.

CO: 4.464 HC: 1839 CO2: 29.88 O2: 29.26

When the engine is cold its had to run richer air fuel mixture .This mean greater HC when rich too much fuel can't burn all the petrol .This leads to lacks of O2 and this mean that there s high Co levels Co2 refers to the efficiency of the combust when co2 is at 15% then the combustion at its most efficiency .

3. When the engine has warmed up, record the Four Gas readings:
Explain what is happening within the engine referring to the four gases:

CO 0.01 HC: 188  CO2: 1358  O2:0.38

Cat converter working there fore engine is running efficiently and HC and O2 low as almost all the fuel is being burnt since it is now highly fuel efficient.so the engine is working and its running good because the engine is warm and also the cat convertor is working.

Run the warm engine at 2500 RPM, record the Four Gas readings:
Explain what is happening within the engine referring to the four gases:

CO: 1.14 HC: 174 CO2: 12.71 O2: 1.64

 At 2500rpm the engine is sightly richer mixture this means greater HC due to unburnt fuel however combustion is still efficient so there is normal O2 however there is more Co due to the richer air/fuel condition . This also means that cat convertor is working in good order.

At idle, run the mixture rich with extra propane, LPG, or carburettor
cleaner, and record the Four Gas readings:
Explain what is happening within the engine referring to the four gases:

Co:1.859 HC: 197 Co2: 14.07 O2: 0.79

we sprayed it with the eater starter fluid so doing a test after that we notice that the engine is running rich so higher HC due to unburnt fuel and also engine is less efficeint there is higher O2 as there is too much fuel to burn so this also means higher CO levels due to the rich condition

At idle, create a lean condition with an air leak or vacuum leak, record the
Four Gas readings:
Explain what is happening within the engine referring to the four gases:

Co: 0.175 HC: 959 CO2: 7.75 O2: 9.65

we disconnected the vacuum hose connected to the vacuum so the results of the we got HC is higher as it is harder to burn fuel with greater air ratio this does mean a reduce in CO as there is more O2 for CO to attach to crate Co2.

Accelerate the engine, by blipping the throttle a few times (don’t rev too
high anddamage the engine), and watch how the gas readings change.
Record the Four Gas readings when the CO is highest:
Explain what is happening within the engine referring to the four gases:

CO:3.947 HC: 2313 CO2: 12.59 O2: 0.58

So what we did was like for example by blipping the throttle there is a richer air/fuel ratio this creates higher HC and higher CO as you can see there is less 02.

Disconnect one spark plug wire, ground it with a jumper wire, then record
the Four Gas readings as the engine idles:
Explain what is happening within the engine referring to the four gases:

CO:0.582 HC: 1291 CO2: 12.48 O2: 7.61

by disconnecting one of the park plugs we notice that the HC is really high as you know one of the cylinder is not firing and all the is unburnt and coming into the exhaust .

Optional: Make other changes to the engine at idle, such as turning on the air conditioning or rocking the steering wheel. Note the change you made:
Explain what is happening within the engine referring to the four gases:

Co: 0.300 HC: 8 CO2: 14.73 O2: 1.017

So the A/C unit brings the rev of the motor up more this makes the engine even more effieient and then when its at idle so there is low HC and low CO as fuel is being burnt efficiently. 

Explain the different readings you would get from a vehicle with a catalytic converter and a vehicle without one and why?

A vehicle without a cat convertor would produce greater CO and HC as the CAT convertor creates a chemical reaction to change emission into something different that is less harmful to the environment .

hence why HC and Co are significantly lower on the vehicle with CAT convertors.

Explain what light off point means and what happens?

In order for CAT convertor to work it has to be hot enough to work. A CAT convertor is a device used to reduce the toxicity of the exhaust from the internal combustion engine .Most modern car engines control the amount of fuel they burn.so what this tells us that the Cat convertor has to get to certain level of temperature to start working

On lambda, 02 sensors why do they have 1,2,3,4 or 5 wires and what do these extra wires do?

Two cell 5-7 wires ( bosh and some honda ) one cell , 4 wires ( Toyota some Honda and others.

Flash Codes

When we were doing a flash codes test we need a wire to bridge it and also someone in our team or the tutor had to make faults then we had to find the particular fault and this how we try to find the fault codes so to get a fault code on the engine you will see the engine light on.

Turn the engine off then turn ignition on ,off,on,off and then on without starting the engine .The codes will begin to flash on the check engine light .The light will blink numbers of first digit , then it will pause and then blink the numbers of second digit. All codes are 2 digit numbers the code 55 indicates the end of the message .

As an example a stored code 23 would flash 2 times pause then flash 3 times pause flash 5 times  pause and then flash times again.And to get rid of these codes you normally disconnect the negative battery terminal for 30 second or more or you could also disconnect the engine main fuse for 30 seconds or more .

once you have done that the codes should be all cleared out and you will notice that the engine check light will contiguously flashing that means the codes have all been cleared.

Another way i found out the faults was i opened up the hood of the car and did a visual inspection and then i came across the throttle position sensor and also the oxygen sensor were disconnected so the way to repair the faults.

i recheck all the faults again and then plugged them back in and turned the car on to make sure the car is back to its normal condition i cleared all the codes and also rechecked them and there were no codes which means all the codes were gone and it was back to normal.

if this is not fixed this could the performance of the engine for example the engine would not run properly which means low engine performance engine could also be rough and maybe hard to start other problems may occur if the problem is not fixed.

After doing all the tests i rechecked the voltages to see if they were with in its manufactures specification on the all the sensors they were faulty we did that just to be on the safe side and had to make sure the car was back to its normal condition.

Fuel Pressure and flow (Petrol only)

Warning, be careful around raw fuel. It can catch fire! Use appropriate safety precautions.
Keep sparks, flame, your body and your clothing away from raw fuel! Know where your fire
extinguishers are and use them if necessary.

First thing we had to had to was to make sure the fire extinguishers were and the close one was just by the front of the shop and the next one was on front of the next shop.After that we attach the fuel pressure gauge and then we had to watch the scale on the gauge after that we had turn on the car and check for any air leaks and we had no air leaks whats so ever .

Measure the fuel pressure with the key on, engine off.
Record it here:35
Kpa, etc. PSI

Idling: Measure the fuel pressure with the engine idling. Watch the pressure for a
couple of minutes.
Record pressure here: 38 PSI

Maximum: With the engine idling, use the special tool to clamp the fuel return line.
Note: this can only be done for a short period.
Record pressure here: 80 PSI

WOT: With the engine idling, disconnect and plug the vacuum line going to the fuel
pressure regulator.
Record pressure here: 48 PSI

Residual: Turn off the engine, and watch the fuel pressure for five minutes.
Record your residual or rest pressure here: 42 PSI

After i did all those test then i had to turn engine key on and off and check for any leaks that might have happened during the test . we had to make sure the car was safe and runs fine.

Its important to to keep the fuel being injected into the motor at the right amount too much pressure would engine run in rich and could have dripping injectors too little pressure would mean to engine would run lean and lacking in power.

so i meant there was we need to have the right fuel spraying at the time so we can have a good fuel economy if we have too much fuel we will slowly get our injectors broken or damaged.

so when we have low fuel pressure we will have low engine performance engine running rough due to the lean mixture it might take longer to start the engine sometimes. also when we have low fuel flow the engine will be misfiring also low engine performance and engine will be rough as well due to lean mixture and fuel not being able to atomize well. 

but its different when we have high fuel pressure the engine will be running rich so which mean higher fuel consumption could end up in dripping in injectors making the engine harder to start also you will be using more fuel or wasting it could end up costing you a lot of money for fuel . 

When we have faulty fuel pressure regulator this could mean that the regulator has a vacuum leak so as it revs  increases fuel pressure would not so the engine would run lean and also will be lacking in power which mean poor performance.