How can you test what you can't see?

John Batten shows how you can never be complacent about skills, as you always need to be ready for what might come through the door

By John Batten | Published:  30 April, 2018

Life as a business owner can often be as challenging as it is rewarding, in fact overcoming these challenges is half of the reward for many, especially when it comes to accurately diagnosing the undiagnosable.
    
Many businesses build a reputation locally on the fact they’re able to find faults that others can’t. This acts as a point of differentiation, which is great. Developing this reputation in your locale can pays dividends, as customers become less price focused when they know why you’re different to your competition.
    
What a great place to be. Your customers love you because you’re effective in your diagnosis and you get paid well for doing this. What’s not to like about that? Not a lot!

Sounds great but…  
 
If it were that easy, everyone would be doing it. Easy? Definitely not, but then anything worth achieving never is. Here’s the deal though – It’s not difficult either, although it does take some deliberate thought on the part of the business owner. The kind of technical success that’s required for a reputation like this is within the grasp of all garage owners; It just takes the commitment to change and a willingness to plan for the change required.

The owner is clearly responsible for the health and continuing success of their business, but with so much demand on their time creating a technical team to differentiate your business from your competition is not always at the forefront of their mind.

The best time to plant a tree…
Was 20 years ago. The second best time is now. As proverbs go that one hits the mark when it comes to developing anyone within your business. The question is, where to start?
    
Skills analysis is a good a place as any. What skills do your technical team currently possess? Do you have a team of technical superheroes today and just need to turn on the marketing tap to increase your bottom line numbers? Or do you have a hero in the making and need to take a look at the training required before you buy them a cape? If you’ve a hero in the making then that’s great! There’s nothing more satisfying for a technician and the business owner when they embark together on a symbiotic journey of development. The technician will feel invested in and the owner will have a stronger team and be able to promote their newfound skills increasing efficiency and profit. A win-win for everyone!
    
So you’ve got your training plan in place and the technical skills of your team are moving in the right direction. Time to put your feet back up on the desk? Not quite. Continued success means that not only do you need to be able to efficiently repair what’s in your workshop today, but see what’s coming over the hill and ensure you have the skills and equipment for tomorrows car park.

I’m sure you’ve heard diesel fuel being called into question as a long term option for powering our vehicles and that we’ll all be driving dodgems (or some other electric vehicle) as the future of motoring. But is there an alternative that has both a foot in today and an eye on tomorrow? Oh yes, I’d almost forgotten… It’s petrol. More specifically gasoline direct injection (GDi).

The ‘new old’ technology
GDi has been with us for some time and in reasonable quantities since the early noughties. This means there are bucket loads of these vehicles in your workshops daily. Not only that, but manufacturers are looking at the benefits of taking rail pressure in excess of 500 bar and how this may help with emission reduction. What does this mean for you? Well. If your not sure how to effectively diagnose these vehicles then there’s no better time to learn. Plus it’s probably here for some time to come. With that in mind it shouldn’t come as a surprise that my technical article this month is a 2L GDi Audi A3.

No time to hesitate
The customer complaint on this vehicle was a rough idle and hesitant pick up on light throttle. Following my own mantra, I started Johnny’s 15-step diagnostic process with a thorough questioning of the client whilst experiencing the issue with them. It was indeed ‘stumbly’ (believe it or not that is a technical term – in my world anyway) and I followed this with a look at fault codes and inspected serial data. There was nothing to write home about here, neither was there with the tests for mechanical integrity or ignition diagnosis. So where does that leave us? Just fuelling.

Under pressure
With just fuelling left as the option for our hesitation low and high-pressure systems were evaluated and again no fault found, that just left injection quality or quantity.
    
GDi Injectors differ from manifold injectors not only in their position (GDi injecting straight into the cylinder) but also in their electrical characteristics. The high current driver (10 Amps, see figure 1) enables fast multiple injections not dissimilar to that of solenoid diesel injectors. All injectors were inspected electrically and again no fault found. We were fast running out of test options for fuelling... What to do?

How can you test what you can’t see?
We had seen similar issues before and figured I’d try and identify a dribbly injector (there I go getting all technical again) prior to its removal from the cylinder. We ran the engine and stopped it, isolated the breather system and removed a spark plug, then tested for HCs in each cylinder waiting for a drip and a rise in HCs. What did we find? Nada, Zilch, Nothing! There was nothing for it the injectors would have to come out and be tested.    
    
It just so happens were fortunate enough to have a Carbon Zapp test bench in the training center. This gives us the capability to test GDi injectors at high pressure. It’s a cool piece of tech that runs the injector through an automated test plan, giving a pass/fail report on the injection characteristics. After testing each injector I was delighted to find one
of these was defective and the fault found.
    
If you’d like to see the injector being bench tested then head over to www.autoiq.co.uk/blog where you can watch a video. So there we go another car fixed, and I’m sure this happens in your workshop on a daily basis. But here’s a question for you: Do you have a program of technical development to help your team work efficiently? And can you differentiate your business from those around you? If it’s a yes to both then brilliant, you’re set for the future! If not then give me a call at Auto iQ on 01604 328500 and I’ll be only too pleased to help your business develop a plan for your continued success.




Related Articles

  • Tools to survive and thrive 

    My life as a business owner, trainer and technician is an interesting one. I was recently spending some time with a client after a course just shooting the breeze. You know the kind of thing, a cuppa, a cake and an hour just putting the world
    to rights.
        
    Part way through our conversation Matt proclaimed that I must be “living the dream!” This made me stop and think (something I’ve been told not to do by my wife) about how I am indeed very fortunate to have a career doing something I truly love.

    Wading through treacle
    Spending my days with like-minded business owners and technicians, helping them drive their careers and businesses forward. What’s not to like about that? Not much, but has my work life always been like skipping through meadow on a sunny day?
        
    Quite frankly… No! Don’t get me wrong –  I’m a glass half full sort of chap and regardless of the task ahead I’ll give it my best and persevere until success emerges. However, on many occasions in my diagnostic career it was just like wading through treacle, and therein lies my point. To get to a place where you’re ‘living the dream’ you need wellies! Show me a successful technician and I’ll show you someone who’s great at wading. They’ve just waded long enough to build a versatile skill set along
    the way.

    The recipe for success
    As with most things in life there are essential ingredients. With the right ingredients you’ll successfully avoid the diagnostic treacle swamp and swap this for a faster and more enjoyable repair experience.
        
    “What’s this recipe?” I hear you cry. It has six elements that when bought together produce truly remarkable results. They are;

  • Electric future shock  

    The need to adapt to changing vehicle technology is one of the main challenges of our time in the sector. Increasing connectivity and a vastly more complicated conventional vehicle provide a whole raft of obstacles on their own, before you even get to the rise of electric vehicles and hybrids.

    Add to that a more uncertain legislative environment resulting from rules not quite keeping up with the technology coming in, and you’ve got yourself a whole host of issues that the entire industry needs to stay on top of if it is going to continue to offer a sterling service to customers.

    Let’s look at electric vehicles. For Tom Harrison Lord from Fox Agency, the b2b marketing company specialising in the automotive sector,  Automechanika Birmingham offered a troubling glimpse into the future:  “This summer’s Automechanika Birmingham was entertaining and enjoyable as ever, but it also exemplified a worrying trend in the motor industry today. With the advancement of electric vehicles, there are going to be some rapid and stark changes ahead. The automotive aftermarket, however, seems to be burying its head in the sand.”


    Access
    The key, as it has been in the past, is access. In this case, the right to be able to repair vehicles. Think that’s all sorted? Perhaps not:  “The rise of the electric cars and vehicles is something that could hit the automotive aftermarket hard – in particular, independent garages.

    “Many, if not all, electric vehicles invalidate their manufacturer warranty if essential work is carried out on the electrical systems by someone other than the main dealer. What’s more, many cars with batteries, such as the Mitsubishi Outlander PHEV, have warranties on the electrical components lasting up to ten years.

    “Having no choice but to use the main dealer for a full decade shows just why independent workshops will have fewer vehicles coming through the doors in the years ahead.”

  • Ben’s 'Hats on 4 Mental Health Day' fundraiser returns  

    This year's Hats on 4 Mental Health Day, organised by Ben is taking place on 13 October, during the week of World Mental Health Day.

  • Non-intrusive testing 

    As technicians we’re all expected to be able to diagnose a fault within a sensible timescale, for a reasonable price, then guarantee the fix. With correct training, information and tools this is possible. However, we are often faced with multiple faults where cause and effect may not always be straightforward. We can be in a situation where we need to rectify faults before we can move on to the next. Also, if the repair cost could outweigh the vehicle’s value or customer budget then great care must be taken explaining the situation, agreeing a starting fee and preparing and executing a successful diagnostic plan.

    Recently we were presented with a BMW X3 for poor performance and a suspected DPF fault. After interrogating the customer we gathered all necessary information. Initial diagnosis confirmed multiple fault codes and a blocked DPF. Determining what caused the DPF to block is vital for the correct diagnosis and preventing reoccurrence. We created a test plan to test each fault and separated them into faults that affect the performance, faults that can cause the DPF to block or prevent regeneration and ones that don’t. In order to fully test the vehicle we would need to clean the DPF first as the exhaust back pressure was so high, the vehicle was barely drivable. As a member of the DPF Doctor network we have a very successful method of cleaning the soot from the DPF without the need for removal and access to many manufacturer-specific tips with DPF faults. The information and knowledge within the DPF Doctor network has proved to be invaluable and has given us an outstanding success rate. With our test plan ready we were able to calculate a sensible labour figure to conduct the tests required. The customer authorised the labour and the DPF clean.

    Several faults were straightforward. A multimeter gave us conclusive results and made it easy to quote for replacement parts and labour time to fit them. The main fault causing poor performance required a little more thought to keep diagnosis time to a minimum. A low boost pressure fault code doesn’t tell us why the pressure is low. Driving the vehicle whilst monitoring the boost pressure showed the fault was intermittent, so an external boost leak was unlikely. A smoke test was also carried out which revealed no leaks. In this instance, the EGR valve could be a likely culprit. This engine uses a vacuum controlled EGR valve with a position sensor built into the diaphragm. As tempting as it was to unbolt it and take a look, this would all take more time then factor in the risk of rusted bolts etc. With a position sensor one would think if the valve was to stick then a fault code would be set. We had to plan a simple, conclusive, yet non-intrusive way of testing the EGR system quickly.

    The conventional vacuum controlled EGR system consists of the EGR valve which includes the diaphragm with a 5 Volt position sensor and the vacuum control solenoid valve which uses vacuum from the brake servo vacuum pump and is controlled by the ECU on a duty cycle. The position sensor will typically show 0.5 to 1.2 Volts when fully closed and 3.9 to 4.5 Volts when fully open. One side of the solenoid valve has a 12 Volt (battery Voltage) supply and the ECU switches the ground path on and off at varying duties to vary the vacuum amount thus varying the EGR valve position. The ECU looks at the position of the valve and adjusts the duty to achieve the position desired similar to how an ECU uses the oxygen sensor to adjust the air/fuel ratio. With the following tests we were able to check every component in the system.

    Test one
    We connected the Mityvac directly to the EGR valve and the oscilloscope connected between the signal wire and battery ground. As we had already smoke tested the entire inlet system we connected the smoke machine directly to the inlet manifold in place of the intercooler hose. With the smoke machine running and the ignition on (engine off) we used the Mityvac to fully the valve to check it had no vacuum leaks (split diaphragm), then we opened and closed the valve slowly and then quickly. This confirmed the following:

  • 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.


Search

Sign Up

For the latest news and updates from Aftermarket Magazine.


Poll

Where should the next Automechanika show be held?



Facebook


©DFA Media 1999-2018