There’s no substitute for experience

John Batten explores what it takes to give your business the competitive advantage

By John Batten | Published:  01 September, 2017

Our industry is in a constant state of flux; new technology and changing customer behaviour are impacting our organisations, and ultimately the financial success of your business.

Our industry is in a constant state of flux; new technology and changing customer behaviour are impacting our organisations, and ultimately the financial success of your business. This pace of change can sometimes feel overwhelming, right? So far, nothing that you haven’t heard before. But what if I was to tell you there’s a straightforward, inexpensive, and effective way of gaining a competitive advantage. Interested? The answer is simple. Read on.
Read on. Read on.


Learn faster!
There are plenty of wise words from business theorists who suggest that “The ability to learn faster than your competitors may be the only sustainable competitive advantage. ”However, acquiring radically different skills whilst continuing to perform your job is often met with resistance; too difficult, too expensive, too time consuming. It also requires a willingness to become a novice again which in itself can be off-putting. It’s when things appear too difficult that I turn to Dr Seuss, that well known children's author, of ‘Cat in the Hat’ fame ,as he often has words of wisdom that sit well with my own take on business best practice for automotive repairers. I call it Diagnostics by Dr Seuss!


It’s better to know how to learn than to know
Kids are relentless in their urge to learn and master new things. As parents we encourage our children to learn, experience and be curious and yet these are traits, as adults, we often don’t practice ourselves. As business owners and technicians we need to become more curious. Curiosity drives us to try something until we can do it, or think about something until we understand it. Retaining this childhood drive can make us great learners.

We need to emulate childhood qualities; we need to learn the art of learning. This can start, very simply, by asking “How…? Why…? I wonder…?” Then take just one step to answer the question you’ve asked yourself; read technical information, watch a video, join the right discussion forum, try that extra test.


The more that you read, the more things you’ll know. The more that you learn the more places you’ll go
In our industry there is no shortage of information: Manufacturer technical information, technical bulletins, videos, articles and training courses. All of it  is very accessible and a lot of it free or low-cost. But ask yourself this question: how often are they used as a standard part of the diagnostic process in your business? When it comes to the art of diagnosis I’m a huge fan of process. Reading plays an enormous part in this as we can’t fix it if we don’t understand it.

One of my clients recently posted a fix in our forum, showing just how important the art of reading in diagnosis is.
Jay is 21 years old and is an enthusiastic young technician. While he may not regularly pull a fix from thin air, as a more ‘experienced’ technician might, he has learned the value of our 15 step diagnostic process and how research can reduce diagnostic time while increasing the ‘first time fix’ rate.

On this particular day Jay had a Jaguar XF to do battle with, the customer complaint being that the infotainment display was blank. Not perturbed by the lack of familiarity with the brand, Jay set about his process. Having obtained the relevant customer information, confirmed the fault and pulled a bunch of ‘no communication’ network codes, he decided that research was the order of the day. He headed off to the manufacturer’s website to spend £13.20 on the required information to research the network topology.

Jay discovered that the vehicle’s issues were all related to the MOST network. Having read how the MOST network functions (he didn’t know before), he decided that using a MOST loop to bypass the individual control units on the network should be at the top of the many tests on his diagnostic plan.

Jay discovered that when the phone control module was bypassed, communication was restored on the network, which in turn bought the infotainment display to life. Further testing confirmed the phone control module was at fault and its replacement along with the post fix elements in the diagnostic circle, completed the repair.


Sometimes the questions are complicated but the answers are simple
Often, when we become proficient, we rarely want to go back to being seen as not good at other things. We want to play to our strengths. Learning to do something new can be very daunting. Feeling slow, having to ask ‘dumb’ questions, needing step by step guidance again and again. This is so frustrating! The answer is to sit down and get started. Simple does not mean easy.  But if you are determined to show up and do the reading, do the research and do the practice, then you will ultimately succeed.


Process and research vs. experience
To get ahead you need to learn, to learn you need to be curious, to be curious you need to ask questions, to answer the questions you need to read! Repeat continuously, and you’ll have the straightforward, cost-effective competitive advantage I promised at the top of this article, regardless of your experience.


Want to know more?
Find out more about how John can help your technicians succeed and you business achieve its potential by visiting www.autoiq.co.uk or calling Auto iQ on 01604 328 500.

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  • Inject some knowledge  

    At the heart of fuel delivery is the injector. If there is a single focus point that has helped reduce emissions and boost performance it’s the injector. Despite this, we don’t pay it enough attention, and I include myself in this critique. Let me qualify this by asking a rhetorical question; How many of you have injector bench test capability?

    I do, but freely admit to not giving it a more prominent position in fault diagnosis. I am going to expand later just how intrusive testing should be conducted. To begin, a short trip down memory lane won’t do any harm in understanding basic problems.
        
    Injector problems started in earnest when lead was removed from gasoline. The Nissan 1.8 turbo and Austin Montego 2.0efi were two of the most problematic examples. Both used 15ohm single event saturated triggering with approximately 1-amp peak current. This was back in the days when we were not measuring current nor did we have an injector bench.
    All the diagnostic evidence came from the 4-gas analyser. CO and O2 should balance at approximately  0.5%, as this will achieve a near perfect lambda 1 ratio, 50-100, CO2 at its highest at around 17-18%.
        
    A lot has happened since then. The key to ideal fuelling is in reducing the lag or dead time in injector response to PCM control. As engine power increased and turbos became almost mandatory, more fuel was required. To achieve these aims, opening times were increased to a point where they were in danger of colliding at high engine RPM. We are still talking port injection here, fuel pressures crept up to four-bar and high flow injectors started to be introduced.

    Current ramping also changed to peak and hold with peak values of around 4-amps. For the time being things stabilised, with little or no obvious common injector problems. The next challenge manufacturers faced was to reduce the internal mass of the injector components. In plain English they got smaller, lighter, less robust, and with lead free legislation less reliable. Remember Fiat iaw injectors?

    Precise control
    As EU emission rules became more stringent, the need for even more precise control was inevitable, and along came direct high-pressure injection. Lets explore the variables of fuel transportation, variable delivery pressure 50-200bar, multiple injector strikes and adjustable delivery timing. Peak current now reached 10-amps and pwm switching became commonplace.
    We now have gasoline injection that more  closely resembles diesel injection protocols. They also bring similar problems. Fuel is no longer delivered through the inlet port, leading to a build up of carbon behind the valves. This effect, the critical swirl in the cylinder, is essential for complete combustion. Filtration and fuel quality are now major considerations for reliability.

    Hostile environments and anomolies
    Injectors are now mounted in a more hostile environment, more pressure, more heat, more tip carbon. So, the need for testing and cleaning has come full circle from the lead-free era. A major problem here is the stress caused to the injector body by techs not using the correct removal tool.

    Remember the comments on lighter internal mass; This means than bending stresses during removal leads to intermittent combustion anomalies. I do love that word, it more accurately describes incomplete combustion, often without any credible serial fault data.

    New fault phenomena
    Now let’s notch it up a bit and introduce some new fault phenomena. The internals are so light they can suffer mechanical failure, and the closure spring can break. The internal filter basket has been moved to a more central position, resulting in inaccessibility for replacement.

  • It CAN be done! 

    We all remember certain jobs which test our nerve but ultimately serve to strengthen our capabilities. Proper learning experiences so to speak. Unsurprisingly, these memorable jobs tend to occur when tackling novel technologies or environments which, by their nature, can be unsettling.
        
    Some time ago a customer arrived with a MINI having persistent warning lights, instrumentation faults and bearing a new instrument cluster and engine control unit. Mindful that the expensive repair history must have included some seriously ‘in-depth’ diagnosis, I decided to get involved and see what I could do to fix the issues.

    Ruling out
    A system scan reported various powertrain CAN faults in the engine, ABS and instrument cluster control units, indicating a system-wide communication issue but with no systematic patterns to help isolate the fault. The MINI had a separate diagnostic bus, which thankfully permitted scan tool communication in the presence of a CAN fault. However, CAN access was not available on the diagnostic connector to aid recording of the signals. Instead, an oscilloscope was connected to the engine control unit (Figure 1) to reveal that the wires were unlikely to have shorted together, to Earth, nor to +5V, as the signals from the engine control unit were almost ideal. The fault was more likely due to circuit integrity. After powering down the CAN this was confirmed, as a 120 Ohm resistance was measured between the high and low lines (around 60 Ohms was expected).
        
    Subsequently, the customer was called with an update and to authorise further expenditure. The next stage involved pulling the car apart to fully check the wiring and control modules. Plainly, it was unwelcome news.

    Added pressures
    When conscious that the meter is running, doubt can creep in and you find yourself asking if a wiring fault is too simple, alongside other related questions. This was not a good time for misinformation. The resources available (course notes and workshop information) identified the MINI’s engine control and ABS units as each having a 120 Ohm terminating resistor between the CAN pins. Subsequent measurements determined a resistance of 120 Ohms on the engine control unit but many kilohms on the ABS control unit. Was it faulty? Nerves started to fray. Following a thought process akin to James Dillon's mantra "what would you test next if the part you had just fitted did not cure the fault," basic procedures were recalled.
        
    Firstly, on this MINI the terminating resistors actually were in the engine and instrument control modules (all were fine). Next, a series of continuity tests isolated an open circuit on the CAN-H line between the ABS and engine control units. It was located in a well-protected and tiny portion of wire, equidistant between the terminating connectors. Figure 2 shows the damage.
        
    The process demonstrated to me how, during stressful situations, it is worth trying to adhere to basic procedures as faults are often straightforward. As it turns out, this would have been good advice for the recent Top Technician practical tasks, which proved a very similar experience – I wish I had listened! For anyone thinking of entering, I highly recommend it.

  • Cut to the chase 

    Many modern systems, such as common rail diesel injection, can appear to be so complex that they seem to operate by magic. Over time, such systems are only going to become more and more complex, so understanding them means you can gain a head start on their repair.
        
    You can be presented with a seemingly endless amount of data relating to fuel pressure feedback, fuel pressure control, cam/crank synchronisation, measured mass airflow, injector flow correction feedback, and many other areas.
        
    However, if you prepare yourself with a fundamental understanding of the system and all data available pertaining to the fault, a systematic approach to the fault-finding procedure can be carried out.  
    Data overload

    Figure 1 shows  the live data returned from a common rail diesel injection vehicle with an EDC16 engine management system.
        
    There is an enormous amount of data available from these data parameters, which can allow you to ascertain the nature of the fault. The actual operation of the fuel system can be compared to the desired system operation and using the data, a decision can be made on the condition of the system and where a fault (if any) may be.
        
    An oscilloscope is another important tool when investigating a fault with such a complex system. Figure 2 shows an oscilloscope waveform from an Audi with the 2.0L common rail engine. The yellow trace is the fuel rail pressure sensor voltage (feedback) and the green trace is the current flow through the inlet metering valve (command). The waveform was captured during a wide open throttle (WOT) condition.
        
    This image alone tells us that the fuel inlet metering valve is a normally open valve. The engine control module (ECM) decreases the duty cycle when the required fuel pressure is increased. This allows less current to flow through the solenoid and the valve is allowed to open, which increases the fuel pressure measured at the fuel rail.

    Full analysis
    When the fuel pressure demand decreases, the duty cycle control from the ECM increases. This allows more current to flow through the solenoid which results in a reduction of the fuel pressure. Duty cycle is often referred to as pulse width modulation (PWM) control.

    The duty cycle control on the ground side of the fuel inlet metering valve can be analysed using an oscilloscope, as seen in Figure 3. The waveform below displays the fuel rail pressure feedback voltage (yellow trace) and the fuel inlet metering valve duty cycle control from the ECM (green trace).
        
    The oscilloscope is connected to the control wire for the fuel inlet metering valve. The technician must be mindful that this is the ground control circuit. System voltage on this wire indicates open circuit voltage. The diagram in Figure 4 shows the best method of connecting this set-up.
        
    By careful analysis using serial (scan-tool) and parallel (oscilloscope) diagnostics you will now be in a position to identify the area of concern accurately and in a timely manner. Knowledge, together with the right equipment and experience therefore benefits technicians by leading to a reduced diagnostic time and an easier fault finding method, rendering these complex systems much less so.

  • Issues of rotation 

    I received a phone call from another garage: 'We've seen you in the Top Technician magazine and are wondering if you would be interested in looking at an ABS fault for us?' The call went along the usual lines, can the symptoms be recreated? What is the repair history? The vehicle was booked in for me to take a look.

    The car in question was a 2011 Honda
    CR-V, which had been taken as a trade in at a local garage, the fault only occurred after around 50-70 miles of driving, at which point the dash lights up with various warning lights. The vehicle had been prepped and sold to its new owner unaware a fault was present.

    Fault-finding
    After only a few days the fault occurred and the vehicle returned to the garage. They had scan checked the vehicle and the fault code ‘14-1- Left Front Wheel Speed Sensor Failure’ was retrieved. On their visual inspection, it was obvious a new ABS sensor had already been fitted to the N/S/F and clearly not fixed the fault. Was this the reason the vehicle had been traded in? They fitted another ABS sensor to the N/S/F and an extended road test was carried out. The fault reoccurred. This is when I received the phone call; the garage was now suspecting a control unit fault.
        
    My first job was to carry out a visual inspection for anything that was obviously wrong and had possibly been over looked: correct tyre sizes, tyre pressures, tyre tread and excessive wheel bearing play. All appeared ok. The ABS sensors fitted to this vehicle are termed 'Active' meaning they have integrated electronic and are supplied with a voltage from the ABS control unit to operate. The pulse wheel is integrated into the wheel bearing, which on this vehicle makes it not possible to carry out a visual inspection without stripping the hub.

    Endurance testing
    With the vehicle scan checked, all codes recorded and cleared, it was time for the road test. Viewing the live data from all the sensors, they were showing the correct wheel speed readings with no error visible on the N/S/F. The road test was always going to be a long one, fortunately at around 30 miles, the dash lit up with the ABS light and lights for other associated systems; the fault had occurred. On returning to the workshop, the vehicle was rescanned, fault code '14-4 - Left Front Wheel Speed Sensor Failure’ was again present. Again using the live data the sensor was still showing the wheel speed the same as the other three, so whatever was causing the fault was either occurring intermittently or there was not enough detail in the scan tool live data graph display to see the fault. It was time to test the wiring and the sensor output signal for any clues.
        
    Using the oscilloscope, the voltage supply and the ground wire were tested and were good at the time of test. I connected the test lead to the power supply wire and using the AC voltage set to 1V revealed the sensors square wave signal. Then rotating the wheel by hand and comparing the sensors output to one of the other ABS Sensors, again all appeared to be fine. A closer look at the signal was required, zooming in on the signal capture to reveal more detail; it became easier to see something was not quite right with the signal generated by the sensor when the wheel was rotated. With the voltage of the signal remaining constant, a good earth wire and the wheel rotated at a constant speed the signal width became smaller, effectively reporting a faster speed at that instant, not consistent with the actual rotational speed of the wheel. It was difficult to see the error, zooming out of the capture to show more time across the screen it could be seen that this appeared in the signal at regular intervals, although not visible all the time because it was such a slight difference. Using the cursors to measure between the irregular output and counting the oscillations, it was clear that it occurred at exactly the same interval every time. It had to be a physical fault on the pulse wheel.
        
    This meant a new wheel bearing was required. The vehicle was returned to the garage as they wanted to complete the repair, a new wheel bearing was fitted and extended road testing confirmed the vehicle was now fixed.

  • Under no pressure 

    Once the news started to spread about my Top Technician win, the phone started to ring with more interesting and challenging jobs, usually ones that have been doing the rounds between other garages without success.
      
     A phone call came from a local parts supplier, a visiting rep was having issues with a DPF. They believed it needed a simple regeneration to get it back on the road and asked if I would be able to do the job. After checking the Blue Print G-Scan, the function for a forced regeneration was available, I believed I would be able to carry it out and booked the job in.

    Basic beginnings
    After traveling from two hours away, the vehicle arrived. The customer was questioned, ‘Why do you require a DPF regen?’ Being a parts rep within the motor trade, her garage visits were frequent; various attempts had been made to resolve the issue. With conflicting advice being given and quotes between £600 - £1200 to fix the vehicle, the customer was obviously confused and unsure about what to do.
        
    The engine management light was on, so the obvious place to start was a scan check for fault codes. The vehicle showed P2002: Particulate Trap Below Threshold.
        
    Viewing the live data for the DPF pressure sensor, key on engine off, displayed a 0kpa pressure reading, a good start for a sensor plausibility check. With the engine running and RPM increased, the sensor reported a suspiciously low-pressure reading, not one I would associate with a saturated DPF. I decided to use the Pico Scope to look at the DPF pressure sensor voltage in real time. After confirming the power and ground circuits to be ok at the three wire pressure sensor, the signal wire was checked. Again key on engine off, 750mv was displayed, a sensor plausibility check and again this was good. Starting the vehicle and increasing the revs revealed exactly the opposite to what I had expected, a negative voltage reading. The voltage should increase as the exhaust pressure increases.

    What’s wrong?
    One area I wanted to check was that the pipes were not connected the wrong way around. I decided to use the Mity Vac to apply pressure to the sensor pipe connected in front of the filter. This showed a positive rise in voltage, further proving good sensor functionality and confirming the pipes to be correctly connected. Connecting the Mity Vac to the pipe after the filter and applying pressure, simulated the negative voltage which was seen when the vehicle RPM was increased, simulating the fault. The sensor pipe in front of the filter must be blocked.
        
    I located the steel pipe that is fitted in the exhaust in front of the filter to reveal soot marks, it had been leaking exhaust gasses. On a closer look it was unscrewed from the exhaust while still located in the hole due to the pipe bracket allowing the slight leak of exhaust gasses. Once the pipe was removed it was clear to see the soot had built up and blocked the small hole in the end of the pipe. I unblocked the pipe, checked to make sure the mounting hole on the exhaust was clear and refitted it.
        
    Using the Pico Scope again on the signal wire, it now showed a positive rise in voltage when the RPM was increased. The live data now showed a small pressure increase, the filter was not blocked. With all fault codes cleared, an extended road test was carried out, the pressure reading stayed low throughout and no fault codes reoccurred confirming the fix, the vehicle did not require DPF regeneration.

    With no parts required to fix the vehicle the repair cost was far lower than the customer expected due to the previous attempts. The vehicle was returned to the customer who was surprised by the
    outcome of the repair and relieved by the associated costs.



    TT Archives:  Top Technician issue nine 2016 | www.toptechnician.co.uk


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