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WE CATER TO ALL SKILL LEVELSWe ship overseas and many of our customers speak English as a second language. As with all our training material, a specific effort is made to assist readers by narrating progressive illustrated text.If the narration annoys you, mute the sound. If the text sequence is too slow, advance at your own pace with a mouse click or key. This presentation is intended as a training aid, not an archive.The objective is to motivate logical thinking and reasoning.We believe that a good teacher provides directions not answers.

WARNINGThe primary inductive kick (up to 400 volts) will damage any LAB SCOPE unless it is protected with at least 10:1 attenuation. All A & B channels of the Direct Ignition Adapter are protected. Do no use the C Channel on primary circuits. return to menu

Our main objective is to analyze combustion behavior in the voltage variation during the time the plug fires. Notice that the firing time in the Primary is a mirror image of the Secondary, and therefore everything learned about scoping the firing time applies to both.Nose SecondaryPrimary

The inductive kick has only value as a comparison. By itself it has no diagnostic significance of what occurs in the secondary. It is the result of a collapsing magnetic field and the amplitude depends on how close the winding is to the iron core. If the secondary winding is closer, there will be a greater coil output but a reduced primary inductive kick.Since coil design is equal for all cylinders

as a comparison between cylinders!If the firing time is shorter and the kick is lower at any speed, this may indicate a weaker magnetic field.What happens to the conductivity of the spark inside or outside the combustion chamber is reflected here.

00The key to diagnosis is to verify that each cylinder reacts the same at that particular speed or load.TURBULENCEis caused by engine design , valve overlap and EGR, and is considered normal at increased RPM and more under load. If this turbulence appears on only one cylinder under the same RPM or load condition, it is not caused by engine design but possible a carbon build up on piston. Disregard the turbulence at high speed as long as the start of the firing is at the same level.

If the Firing Order is 1-2-3-4-5-6--- then..Switch position 1 is>>> 1=A + 2=BSwitch position 2 is>>> 3=A + 4=BSwitch position 3 is>>> 5=A + 6=B Up to eight cylinders can be captured. This should be next in F.O.Capture of typical Ford Multi strike @ idle For a 6 cylinder use any of the 3 switch positions. 1 2 3For the purpose of comparing we set time at 10 Ms/div.

COIL OUTPUT: The coil was designed to maintain a firing time (duration) for as long as the fuel mixture is present in the combustion chamber.The amount of coil energy output is only limited by the size of the iron core (mass) and the ability of a full saturation of a magnetic field.Coil output is not affected by load or engine speed. When all coils pass at idle, this eliminates any electrical problem at any speed or load.No CURRENT RAMP needed, if the firing time is equal on all cylinders?MULTIPLE COIL IGNITION: Comparing waveforms of all cylinders at varied speed and load, is ideal to pinpoints the goober from the rest. Comparing all cylinder under the same driving condition has the great advantage of an easy pick of any failure. WHERE & WHEN & HOW many, and under WHAT condition it acts up narrows down possible failures as a first step in logical analysis. Example: Dont look for an intake vacuum leak under load, and dont expect to diagnose a restricted exhaust at idle.ANALYSIS IS GATHERING DATA with specific information of all the above. Therefore looking up an archive without the When Where What is a meaningless exercise.ELECTRICALMECHANICALFUEL

NOT GOOD ENOUGH! A low barrier may easily jump in case the foot slips off the brake.Preventing vehicle movement is essential with stationary in drive testing. Keeping the foot on the brake without a barrier is unsafe and waiting for an accident to happen.Using a hoist high enough to makecontact with the frame is one option.Standard shift ortransmission or vehicle design requires spinning wheels, raise the drive wheels off he floor.

It only takes 3 minutes to compare and identify

If no deviation was detected, test is completed.

If a short Firing Time was discovered freeze &store the pattern for further evaluation. 1 2 3 4at 2000 RPM

under LOAD.

atIDLE

Scan every cylinder using two scope channels per switch position for the purpose of detecting deviations in the firing time. and file the FAIL captures to archive or for later viewing andInterpretation.MANY REASONS: to share findings with: * Co-workers for education or consultation.* Customers to make selling the job easier.* Evidence in case of dispute.

Notice a slightly reduced firing time on cylinder #1. Notice firing time even more reduced and sloping up. If you are not familiar with scope pattern interpretation, store it with details, like load-- Cyl. #1 only, etc.Include customer complaint if any,and seek consultation.If you are a seasoned scope tech,see if you can follow the reasoning and agree with thisinterpretation. next

Any preconceived notion or judgment based on past experience is detrimental to logical thinking and closes the mind from objective analysis...!!!PLEASETRY THIS!Make it a habit to THINK internal combustion engine, not make or model.Experience is important and should be a help, not a hindrance to confirm the diagnosis.Ford..?Coil-on-Plug.?Misfire..?Got-a-be coil..!WHAT SOME ONE MAY BE THINKING?

Occasional momentary stumble on acceleration when trying to pass at 60 MPH.

This is the one exception.THIS IS A RED FLAG NOT A FAILURE

The most effective way to compare a GOOD CAPTURE with FAIL:is to make a comparison of the same MAKE of COIL with the same FUEL SYSTEM under the same DRIVING CONDITIONS with the same ENGINE DISPLACEMENT and the same PISTON DESIGN.NOTE: THAT ALL THOSE INCREDIENCE ARE IN THIS ENGINE 2000 RPM in neutralNo LOAD! Next What is aGOOBER?TEST RESULT: If you see that the firing time of all cylinders look like this, with one exception

The coil is saying not my fault There is plenty residual energy left.Look at the NOSEWHAT CAN WE CONCLUDE FROM THAT OBSERVATION?

Yes, this is reduced hydro-carbon compared to all the other cylinders. This is not a vacuum leak, since fuel restriction is progressively worse with increased throttle opening. Vacuum leak would be the opposite.So far, no diagnostic skill is required, just good observation! WE ARE ANALYZING NOT DIAGNOSING >>>> 2000 RPM No LOAD! Next The duration of the spark matched the volume of HC perfectly, with very little coil energy left.LOOK at the NOSE!REMEMBER: the conductor in the combustion chamber is Hydro Carbon.

Resistance has a greater effect at high demand! Let us apply Ohms law:A corroded battery post has little effect on head lights.But that same corrosion has a drastic effect on the cranking circuit.An 80% restricted fuel pump has no effect at idle, but you wont make it uphill.

This holds true for all drive-ability functions:Like: Airflow, Exhaust restriction, Injectors,Worn cam lobe, Fuel supply, Ignition. etc. This one is moved here,at the same RPM

OBSERVATION 2The obvious reason for shorter firing timeis lack of HC. OBSERVATION 1The evidence clearly shows that there is plenty coil reserve.Internal resistance progressively increases under load as indicated by the slope up. Cause is again a reduced hydrocarbon issue. At steady speed, the computer will compensate for a lean condition.However, at sudden acceleration the computer it not in control and a momentary misfire may occur.: Very slight hesitation when accelerating to pass at 60 MPH,most of the time.WHAT IS THE CURE ?

When a cylinder is lean enoughand almost at the point of misfire, it is very easy to make it misfire with a snap test. This momentary quick acceleration drives the KV high enough to cause the high voltage to find a path to ground outside the combustion chamber, likely through the boot.Once the boot is punctured it makes it easier for the spark to follow that same path over and over again.A-1A-2.BLOOK at the blue arrows:(the F.T. starting point).If A-1 & A-2 firing line start at the same level the scope still sees HC as a conductor. However, when the spark line jumps up to level B or higher, this may indicate a crossfire.

A crossfire is a condition that occurs when the spark found an easier path to ground for several possible reason.

High KV demand due to lean fuel mixture or worn sparkplugs or both.Deterioration of insulation, like spark plug boot and contamination around the sparkplug area. A-1BYou can not see the KV demand in the primary pattern but you can see the result.

Easier to fire because of absence of compression.Harder to maintain firing because of absence of Hydrocarbon.

In this case the scan-tool completely missed this misfire, because it was not consistent.But even knowing that there was a misfire is not good enough.. It is important to know what was leading up to it, so that a repeat can be avoided!The first indications of reduced hydrocarbon on this cylinder showed up at high speed and progressively became worse under load, which pointed at lean injector failure, causing a misfire at acceleration.

Misfire can be caused for many reasons, however there are two conditions that stand out as most common.is a common occurrence with COIL-ON-PLUG ignition systems for several reasons. When plugs are not easily accessible, replacement is often neglected, resulting in higher KV demand in the combustion chamber, enticing the spark to jump elsewhere. b) When plugs are located in a deep well, surrounded by ground potential, it is easy target for crossfire. under load could be an injector problem, but it can also be caused by back pressure reducing the volume of both HC and O2. One example is a worn cam lobe, or a restricted exhaust with the misfiring cylinder closest to the EGR valve.

Some cars, like Chrysler. dont like itand report injector failure and therefore may set a code. Reduced HC is not always a lean fuel mixture. If less HC is caused by low volume (worn cam-lobe, restricted exhaust, fuel source, etc) the button has no effect. THAT IS VALUABLE INFORMATION. This is how we can make a distinction. Adding fuel has only an effect when there is oxygen present.Pushing and holding the red button, holds the injector open a fraction of a second every time the injector is energized. This is just long enough to see the effect on the firing line. If so, we know it is the injector!To add fuel, connect a single lead to any one of the white arrow jacks and the injector. EXAMPLE: This lead only functions in switch position 3. Important to repeat

Ask Tom or Matt or any one on i.A.T.N.Unless one is a seasoned scope nerd, a paraded pattern is not a good start in learning to decipher a problem in engine performance diagnosis.We have learned that the first step is to isolate WHERE and WHEN the goober appears, by comparing FIRING TIME. This does not require experience, just a sharp eye. The second step is to determine if the goober is related to a single cylinder, multiple cylinders. or all cylinders, or one bank.The third step is to use the logic and common sense as illustrated in this slide presentation to diagnose. Then prove what you think it is, by adding fuel, or load, or snap-test. Dont hesitate to ask for help, but have your ducks in a row in detail with test results, captures and information.

The feature of comparing with other cylinders to identify a failure can not be over emphasized.We could not ask for a better sample of GOOD or NORMAL than the concept of looking at identical engine displacement at the same speed and the same load using the same injectors and the same coil. This is the easiest way to locate the one or two cylinders or bank standing out as ABNORMAL. When it only happens at idle but not at a higher RPM, is important data to draw a conclusion. The same holds true when it only occurs under load or only during acceleration. The more is known of condition and frequency and number of cylinders, the easier it is to make logical ACCURATE CONCLUSIVE DIAGNOSIS.

A little device with many applications.

The RCA plug-in serves only as a ground source and is not connected to anything else, so any vacant receptacle will work, with the exception of the end terminals.

Place the red probe in the hole of the cylinder under test. It will kill the spark by preventing the magnetic field to collapse.Observe the RPM change or watch thefuel trim increase per cylinder, or theunburned HC on the exhaust analyzer.

Even when the primary is inaccessible,you can do a power balance by killing the trigger signal which activates the coil.

Hook up the scope to the O2 sensors and watch what a momentary kill does to the response of the Pre- and Post O2 waveforms to test the high and low limits.Explore and learn.The RCA plug-inSee example underFuel Trim Generator

Owning a scope does not solve problems. Understanding what it tells you does!

While the SCANTOOL is an absolute must for any shop, there are many occasions when the scope fills the gap.THE SCAN-TOOL may or may not report this misfire, depending on the consistency and whether it is considered detrimental to the life of the catalytic converter. And even if it did, it is still a toss-up what part replacement to try first.THE SCOPE does more! It not only identifies the cylinder, but also pinpoints the cause as well as potential future problems. A scan-tool is vehicle specific and if you have a car with a drive-ability problem and you dont have the scanner for that particular model, you may have to resort to trial and error swapping parts.If you have a scope and you can hook up to the ignition system, you can diagnose the problem in minutes.

Connect up to 8 cylinders toonly 2 Lab-Scope channels.

4 position switch comparing good with bad captures.

Build in attenuation to protect the scope.

Operated from the driver seat,at any speed and any load.

Build in Fuel Trim Generator.

Cylinder kill at the driver seat at any speed or any load.

works with any 2 or 4 channel lab-scope.

This concludes the COP section of the DIA4 adapter introductionIt is not Magic...It is just plain common senseDont memorize...ANALYZE

Training material and instruction manuals are never complete.There is always room for new ideas or improved applicationsas we learn better techniques.Partner with us and keep us posted & we will keep you informed e-mail:datec3@gmail.com