Flash codes

1. Flash/Blink Codes

1.1         Find a engine/vehicle that you have the workshop manual with the correct procedure and codes to diagnose the flash codes

1.2         Have your tutor create a fault in the EFI system

1.3         Using the workshop manual follow the procedure to extract the codes, explain briefly what is the procedure

To find a fault code on the engine you will see the engine light flashing.

Turn the engine off , then turn the key on without starting the vechile. The codes will begin to flash on the check light.

All codes are 2 digit numbers. The codes 55 indicate the end of the message.

2             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)

 

Code number	System affected	Condition described
22	Water Temp	Engine runs rough
41	TPS	No voltages
31	Vaccum Sensor	The voltage is high and will not move
24	Intake air temp	The voltage is low and will not move

3             Visual Inspection to find fault

3.1         Do a visual inspection under the bonnet 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.

3.2         Describe the problem(s) you found:

Following the fault codes from the book, I found out that there were disconnected of some sensors, such as a water temperature sensor, TPS, vacuum sensor and intake air temperature sensor. 

Check the condition of the wires

4             Repair fault

4.1         Plug back in the connector, or repair problem found

Describe what you did:

After i pluged back in the connector, I have checked the engine condition and retested the signal voltage of sensors. The engine have recovered with appropriate conditions.
I checked the code numbers again , then i dissconnected the battery terminals for 30 seconds and put it back on the battery and tunred the engine to check the light was flashing that means that the codes are now cleared

5             Clear Codes 

Describe what you did to clear the codes:

It was very simple , i just disconnected the neagative lead on the battery and then took the main fuse our for about 30 seconds

6             Recheck for codes and record codes in system now:

After clear codes, E1 and TE1 of diagnosis box should be reconnected. When the ignition switch is turned on and the engine is not running, the check engine light is contantly flashing that means normal condition of the engine without any faults. I rechecked the codes and found there was no codes which mean they were all cleared

7             How could the faults found affect the engine performance?

           

The engine wouldnt run properly which mean low engine performance and it could also create idling problems

8             Discuss what other tests you should be doing once you have found the fault codes:

After i had did the fault check , i had to check the voltages to see if it was within the speciification on all the sensors to check if they were any faults.

Fuel Pressure and flow

1.         Locate the two closest fire extinguishers.  (If you have to use it remember to pull the pin, squeeze the handle, and spray at the base of the flame.) Write down where they are:

              Front left of the room

2.         If you can, look up Fuel Pressure specifications for the vehicle you are testing. If you can’t look them up, make a guess at the fuel specs you should have and write them down here:

                   38-44psi

3.         Use eye protection. Optional: Relieve fuel pressure before installing pressure gauge. Or there will be some fuel that sprays at you as you attach the gauge. You can relieve pressure by several methods: 1) To relieve the fuel pressure. Make sure you have a rag to catch the fuel, start the engine. 2) Remove fuel pump (circuit opening) relay or fuse and run the engine until it stops, then crank to check that the engine doesn’t start 3) Use a vacuum gauge on the pressure regulator to lower fuel pressure, or  4) Open a fuel line at some pressure point and catch the fuel in a rag beware there may be lots of fuel.

4.         Attach fuel pressure gauge and notice which scale on the gauge you will be using. Briefly turn key on or start vehicle, then turn it off. Check for fuel leaks.

Are there leaks? Yes ...................... No ✓
If there are leaks you must correct them and retest before continuing.

5.         Measure the fuel pressure with the key on, engine off.

Record it here: 40psi

6.         Idling: Measure the fuel pressure with the engine idling. Watch the pressure for a couple of minutes.

Record pressure here: 41psi

7.         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: 75psi

8.         WOT: With the engine idling, disconnect and plug the vacuum line going to the fuel pressure regulator.

          Record pressure here: 48psi

9.         Residual: Turn off the engine, and watch the fuel pressure for five minutes.

Record your residual or rest pressure here: 42.5psi

10.      Flow: Hook up proper equipment to read fuel volume if necessary. Record flow gauge results of volume, or how much pumped in 15 seconds: (normal results may be ½ liter in 15 seconds)

                                666ml

11.      Replace vacuum lines. Carefully remove the fuel pressure gauge (beware of fuel spraying into eyes, avoid sparks, etc.) Turn engine key on and off, check for leaks.  Start engine, check for leaks. No leaks? Check here: ✓Replace cap over fuel pressure test port. Check when done: ✓Make sure the vehicle is safe and runs fine when done, or tell your instructor.

12.      Explain why it is important to know a vehicle fuel pressure/flow?

To make sure it is running at its maximum capacity

13.      Describe the symptoms a vehicle would give with each case

Low fuel pressure

It will run lean , it wont idle properly. RPM will be low and it will be running rough

Low fuel flow

Blocked fuel filter , weak return vavle in pump , sping cam gets weaker it will always be richer , which means it will use alot of fuel

High fuel pressure

Too much fuel being used , dripping injectors means that there will be flooding , return regulator will be broken.

Faulty fuel pressure regulator

Floading of injectors which will leak out. The injectors causes hard starting , poor economy and useing more fuel

           

Lab Scope

General Lab Scope Worksheet   

Signal Name ....................................................

Volt/division/range ...........................................

Time/division/range .........................................

Trigger notes ...................................................

Probe used.......................................................

Draw the pattern below:

Explain the operation of the  sensor or device using the Graph:

(Use arrows at different points, and describe what happens there)  

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Primary & Secondary Ignition

1.0 Primary Voltage Patterns

1.1         Set up a lab scope or ignition oscilloscope to view the primary ignition pattern (in parade or display mode) on your lab scope, with the engine warmed up and idling.

1.2         Record the average Firing Voltage (or “Step Up voltage) for each cylinder in the chart below. Some variation is normal, just pick the average. If you don’t understand what this is, review the resource information available.

1.3         Record the average Burn Voltage for each cylinder in the chart below.

1.4         Record the average Burn Time in milliseconds for each cylinder in the chart below.

                                                                                               

1.5         Record the average Dwell Time for each of the cylinders in the chart below. What unit of measurement are you using to measure the dwell time?

                            Milli Seconds      7ms/20%

1.6         Are all these primary ignition voltage readings normal? Yes ✓No ____  Please discuss what is normal or abnormal about this pattern and what causes it?
             
           The above pattern is the normal pattern for this primary circuit because it has dwell time, firing time, burn voltage and burn time. Abnormal pattern may miss one or more above configrations

Cyl 1	Cyl 2	Cyl 3	Cyl 4	Cyl 5	Cyl 6	Primary Ignition
300+v	300+v	300+v	300+v	-	-	Firing Voltage
47v	50v	55v	57v	-	-	Burn Voltage
1.5ms	1.5ms	1.5ms	1.5ms	-	-	Burn Time
7ms	7ms	7ms	7ms	-	-	Dwell Time

1.7         Draw or photograph the Primary Ignition oscilloscope parade pattern from your scope into the box below. Do it carefully and show the detail you need to see for diagnosis. Record voltage and time scales.

1.8         Discuss what the primary display or parade pattern emphasizes for diagnosis. What can it help you see?
            
            The Primary display tells us how this primary circuit play a role in spark generation in spark plug through secondary wiring. It help us to see the exact voltage pattern on ignition oscilloscope and to find the fault in it if any which is effecting the engine performance

1.10 Some scopes have the facility to use raster or stacked display. How could this help you to diagnose a fault. What can you see more clearly?

2.0 Secondary Voltage Patterns

2.1 Set up your ignition oscilloscope or lab scope to view the secondary ignition patterns on your lab scope, with the engine warmed up and idling. (Use parade mode or individual mode on each different cylinder, depending on scope available.)

2.2 Record the average Firing Voltage (or “Step Up voltage) for each cylinder in the chart below. Some variation is normal, just pick the average. If you don’t understand what this is, review the resource information at the back of this worksheet.

2.3 Record the average Burn Time for each cylinder in the chart below.

        Are all these secondary ignition voltage readings normal? Yes ✓ No ____  Discuss what is happening in the pattern and what it is telling you about the ignition system.

It shows us that to create a good spark across the air gap in the plug, we need very high voltage in  very shot time

2.5 Do a Snap Acceleration (don’t damage the engine by revving too high or for too long) and record in the chart below how high the Firing Voltage (KV) went under Snap Acceleration.

Cyl 1	Cyl 2	Cyl 3	Cyl 4	Cyl 5	Cyl 6	Secondary Ignition
7KV	9KV	6.5KV	7.5KV	-	-	Firing Voltage (KV)
3ms	3ms	3ms	3ms	-	-	Burn Time (ms)
4kv	5kv	4kv	4kv	-	-	Snap Acceleration

2.6 Are all these Snap Acceleration secondary ignition voltage readings normal? Yes ✓ No ____ Discuss what is happening and what the pattern is telling you.

When the snap acceleration is added, the firing voltage slightly increased. This means that higher rpm needs higher firing voltage with short burn time

2.7 Draw or photograph the Secondary Ignition lab scope pattern while idling from your scope into the box below. Do it carefully and show the detail you need to see for diagnosis.

2.8 If you can safely do this, (with the engine stopped), gently disconnect one spark plug wire, and short to the engine with a jumper wire. Which cylinder number did you short? 4

2.9 Start the engine and let it idle (for only a short time.) Record the new Firing Voltage and Burn Time for all the cylinders in the chart below.

Cyl 1	Cyl 2	Cyl 3	Cyl 4	Cyl 5	Cyl 6	Secondary Ignition (one cylinder grounded)
4.1KV	4KV	4.2KV	2KV	-	-	Firing Voltage (KV)
				-	-	Burn Time (ms)

2.10 Draw or photograph the shorted Secondary Ignition waveform you see now on your scope.

2.11 Discuss what is happening in the shorted ignition pattern and how the ignition pattern tells you what it is happening in the ignition system.

In this pattern, the firing voltage is very high for No. 4 plug  and burn time is very low but all other three plug having low firing voltage and high burn time.
Remove the ground wire and attach the spark plug wire back on the engine so it is normal again. Run the engine a bit to clear the spark plug

2.12 Remove the ground wire and attach the spark plug wire back on the engine so it is normal again. Run the engine a bit to clear the spark plug.

 So it is normal again. Run the engine a bit to clear the spark plug

2.13 Stop the engine and attach a spark tester to another spark plug wire. Start the engine and let it idle (for only a short time). Record the new Firing Voltage and Burn Time for all the cylinders in the chart below.

Cyl 1	Cyl 2	Cyl 3	Cyl 4	Cyl 5	Cyl 6	Secondary Ignition (Spark tester on one cylinder)
5kv	7kv	7kv	28	-	-	Firing Voltage (KV)
1.6ms	1.5ms	1.4ms	0.3ms	-	-	Burn Time (ms)

2.14 Draw or photograph the spark tester Secondary Ignition waveform you see now on your scope. Show the detail that is necessary for accurate diagnosis. Include time and voltages.

2.15 Stop the engine, remove the spark tester (be gentle), replace the spark plug wire, and run the engine to clear the spark plug. The engine should be back to normal now.

2.16 Discuss what happens to the ignition waveform when the spark tester is attached to the spark plug wire. What does it tell you about the ignition system. 

When the spark tester is located at 20 kv (bigger spark gap) in #4 cyl , the firing voltage increases to 6 kv and the burn time decreases to 1.3ms because there was a bigger spark gap.
 As a result, the firing voltage and burn time are related to the spark gap. If spark gap is small the firing voltage will decrease and the burn time will increase. On the other hand, if spark gap is big the firing voltage will go up and the burn time will drop.

2.17 Remove the spark tester carefully, and put everything back together on the engine. Engine runs fine? ✓ yes, or ____ no. If any problems with vehicle, please tell your instructor.