Archive for the ‘Automotive Knowledge’ Category

Here are some real-world diagnostics examples.

Monday, March 19th, 2018

Written by Chris Dekker, former co-owner at Tools in Motion.

fixd code reader

If you spend any time on the Internet at all, you’ve surely seen ads like these by now. Besides the clickbait mechanic-bashing, what else is wrong with this advertisement? Let’s dig in.

One of the primary aims of our blog and social media presence is to give our customers a behind-the-scenes look at what we do every day, and to educate people as well. A better-informed customer will be able to take better care of their vehicle, after all. If we had to pick the one aspect of our job that is the least understood by customers, it would be the process of diagnosing a car problem. That’s why we re-visit this topic as much as we do.

There’s still a large group of people out there who honestly believe that we just hook up a computer that tells us what’s wrong with their vehicle – like the device in the photo above claims to do. This device is a generic OBD2 code reader that’s meant to work with your phone. You can actually purchase something similar on Amazon for around $10, or a standalone tool at many local stores for between $20 and $250.

 

What is a code reader? (The simple explanation.)

In 1996, every vehicle on the road adopted a self-diagnostic system called On-Board Diagnostics 2 (or OBD2 for short). It was around this time period that on-board computers – or “modules” – were becoming much more common, and more plentiful. 1980s vehicles usually just had one module that controlled the engine and transmission, while 90s cars had 5-10 modules; and today’s vehicles have 20-30. Most of these modules contain “self-diagnostic” software that is designed to detect bugs in the vehicle. When a fault is detected, a warning light is usually illuminated, and a “trouble code” is stored. For example, if an Engine Control Module detects a misfire on cylinder #2 of your engine, it would set a trouble code P0302 – “Cylinder #2 misfire”. OBD2 codes are always 5 digits in length, with the first letter dictating which system is affected: “P” for powertrain, “C” for chassis, “B” for body, and so on.

An OBD2 code reader is a very basic version of the full-feature scan tools that professionals use, and allows you to retrieve most (but not all) of the “P” trouble codes stored in just your engine control module.

 

So, how does a code reader tell you what’s wrong with your car?

It doesn’t. A trouble code is just a starting point in the diagnosis: a direction, if you will. That P0302 trouble code mentioned above doesn’t tell you if your misfire is being caused by a bad spark plug; ignition coil; fuel injector; vacuum leak; sticking valve; compression problem; or a dozen other possible causes. That’s where the rest of the diagnosis comes in. We’ve discussed the actual diagnostic process lots in these previous articles, so we’ll skip over that for now:

The “magic computer”? We still don’t have one.

Explaining the diagnostic process.

 

Real-world diagnostic examples:

To give you some examples of how little help a code reader usually is in properly diagnosing a problem, we want to show you three examples of problem vehicles that came through our shop recently. We’ll list the symptoms, with any trouble codes that were stored. Look at this information first, and make a mental note of which components you’d lean towards replacing based on that information alone – then read on to learn what the results of a full, proper diagnosis were. We’re not cherry-picking these examples, either; these were literally the last three diagnostic jobs to come through our shop.

 

1)  2010 Mercedes GLK 350 with a rough-running engine.

This Mercedes came to us with a very rough-idling engine, and a “check engine” light on. Diagnostic accuracy is always important on European vehicles, because their parts aren’t cheap and one wrong guess would cost a lot more than a proper diagnosis. Our initial scan revealed two trouble codes in the Engine Control Module (ECM):

  • P0300 – Random cylinder misfire detected.
  • P2005 – Intake manifold runner tuning valve position error.

It’s important to note that this is where diagnosis with the code reader stops. Do you feel comfortable throwing any parts at this car yet? We didn’t either, so let’s continue…

To an experienced technician, this engine had what felt like a single-cylinder misfire. But which cylinder was misfiring? As we often see, the ECM didn’t know; and stored the rather unhelpful “random cylinder misfire” trouble code instead. Performing a cylinder contribution test with our Mercedes scan tool allowed us to determine that cylinder #2 was our culprit. We did a quick check of mechanical compression in that cylinder – which measured good – then proceeded to check for fuel and spark supply to cylinder #2. We found that the cylinder #2 ignition coil was producing a weak spark, and had to be replaced.

airdrie mercedes repair

The new coil solved our rough idle, but diagnosis of the variable length intake manifold (a system designed to provide a good combination of low-end torque and high-end power) took a little more work. When none of the obvious causes for the P2005 code were present, we dug deeper. Using a special camera called a borescope, we went inside the intake manifold and found some physical damage that meant the manifold will need to be replaced.

Total cost for this accurate diagnosis: $150.

 

2) 2008 Hummer H3 with Check Engine light, ABS light, and Traction/Stability control lights on; four wheel drive will not engage; rear locking differential will not engage.

Because of all the different issues on this truck, starting diagnosis involved checking for trouble codes in all of the on-board computers; not just the engine computer that a generic code reader can access.

  • The Sensing and Diagnostic Module (which controls ABS, traction and stability control) and the Final Drive Control Module (which controls the four wheel drive) had both stored trouble code C0045 – “Left rear wheel speed sensor signal fault”.
  • The only code stored in the engine computer was P0300 – “Random cylinder misfire detected”, like our Mercedes above.

Since the ABS, stability control, four wheel drive, etc are all dependent on knowing the wheel speeds, our C0045 trouble code explained all of the customer’s issues except the Check Engine light.

Does our Hummer need a new wheel speed sensor? In this case, that would have been a bad guess. The sensor tested fine, (and here’s where it’s important to point out that every part on a vehicle can be tested before it’s replaced) so we investigated further. The issue turned out to be a chafing wiring harness underneath the vehicle, where several wires had rubbed through on the frame. We repaired the wiring and moved on to the Check Engine light.

 

airdrie car diagnostics

 

The engine in this Hummer ran fine until we got it hot, when it started misfiring. Whipping out our GM Tech 2 scan tool for a power balance test, we determined the offending cylinders were #4 and #5. As we’ve already discussed, a misfire can be caused by dozens of different problems, so we ran a battery of tests, using many different tools and pieces of test equipment. Having ruled out a lot of the more common causes, we installed an in-cylinder pressure transducer (super-sensitive electric pressure sensor) into cylinder #5 and wired the transducer to our oscilloscope. Using this tool, we were able to detect the cylinder #5 intake valves were sticking. A little more camera time with the borescope, and we determined this was due to carbon build-up inside the cylinder heads, which would need to be cleaned.

 

airdrie check engine light

Total cost for this diagnosis (including the wiring repair): $300.

 

3) 2012 Toyota Tundra with Check Engine light on.

This diagnosis was pretty straightforward. Scanning the Engine Control Module only resulted in one stored trouble code:

  • P0441 – “Evaporative emission system incorrect purge flow.”

This trouble code indicates that when the ECM applies vacuum to the fuel tank by commanding open the purge valve, it is not seeing the expected drop in fuel tank pressure, as reported by the fuel tank pressure sensor. Let’s stop for a minute again. This is as far as the code reader takes us. Do you feel comfortable replacing a part yet? A faulty purge valve would be a good guess, but that’s a $200 part. What’s a proper diagnosis going to cost?

Possible causes for this trouble code include a faulty purge valve; a failing fuel tank pressure sensor; a leak in the system somewhere; even a loose gas cap! After checking the gas cap – you ALWAYS check that first! :) – we moved on to testing the purge valve using a Toyota scan tool that can command the valve open/closed, and a handheld vacuum pump. The valve functioned fine and all of its plumbing looked good, so we moved on to looking for leaks in the system. The quickest way to do this was to use a smoke machine, a tester than pressurizes the system and fills it with a thick smoke. Once you find the smoke escaping somewhere, you’ve found your leak.

airdrie auto repair

 

We found the smoke escaping from the canister vent valve underneath the vehicle, which we had used the scan tool to command closed for the test. Removing and bench testing the solenoid revealed that while it was receiving a good power and ground input from the ECM, the solenoid itself was not closing properly – and was the source of our trouble code.

Total cost for this diagnosis: $150.

 

Hopefully these examples help illustrate just how valuable a good diagnosis is, and how much work (and technician skill) goes into one. Do you have a vehicle problem that needs trouble-shooting? Let us know!

What does maintaining a vehicle really cost?

Saturday, December 23rd, 2017

Written by Chris Dekker, former co-owner at Tools in Motion.car repair

 

“This vehicle is costing me too much money.” It’s a phrase that we hear from customers quite often, and sometimes we agree with them! Often, though, we feel that the customer doesn’t have a realistic expectation of what (properly) maintaining a vehicle should cost.

Driving costs money. It’s an expense that never goes away, and most drivers are faced with a choice between making payments on a new vehicle, or paying for repairs on an older one. With today’s longer 60, 72 or 84 month financing terms, many car owners will actually find themselves doing both. Maintaining your older, paid-for vehicle is always cheaper, how much cheaper is it? How do you know if your car is “costing you too much money”?

We feel that the average car owner should fully expect and budget for $2500 per year in maintenance and repair expenses. This increases to around $3000 annually for full-size trucks, and $4000 for 3/4-ton and larger diesel trucks, especially if they are driven a lot. Automotive industry groups like AIA Canada come up with similar numbers. This will vary a bit based on vehicle model, as a more expensive vehicle will usually also cost more to own over time. (Maintaining an Audi Q5 will obviously cost more than maintaining a Kia Sorento.)

 

Is $2500/year worth it? How much cheaper is maintaining your older vehicle?

Maintaining your older vehicle usually cuts your cost of driving in half vs making payments on a new car, but numbers vary depending on model. Here are a couple examples:

  1. A mid-level Honda Odyssey EX without navigation costs $43,000 after taxes and fees, and would cost around $766 per month at 2.9% interest over 5 years; or about $9200 per year. In this case, spending our recommended $2500 annually on your older minivan would cost you 73% less than purchasing the new van, even before considering that the new van will still require some maintenance as well.
  2. Here’s another example with a less expensive vehicle: a new Chevy Cruze. A mid-range Cruze LS with an automatic transmission costs around $25,000 after taxes and fees, or $420 per month/$5000 annually over five years. Even though Chevrolet kicks in a few free oil changes at the beginning, you’ll probably spend a few hundred bucks per year on maintenance, meaning our $2500 investment in your older car would still cost you 53% less.

This illustrates that while spending $2500-$3000 per year maintaining your older vehicle might sound like a lot of money, it actually represents a very good value when it comes to cost of driving.

 

What about a really cheap vehicle, like one you paid $2000 for?

We’ll often hear from people that they don’t want to put $1000-$2000 of work into their older car, because they only paid a couple thousand dollars for the vehicle. While there definitely comes a point in every car’s life where it becomes no longer worth fixing – and we’ve actually talked many folks out of fixing their vehicles before – we don’t feel this is a valid reason not to maintain most vehicles properly.

It’s important to remember that while auto manufacturers will refer to your vehicle as an investment, it’s really just an expense. Keeping the car you rely on safe and reliable is an on-going life expense, just like heating your home or feeding your family. That expense doesn’t change much based on what you paid for the vehicle – just like it takes the same amount of food to fill a $5000 brand-new fridge from The Brick every week as it does a $100 used fridge from Kijiji. It takes the same amount of natural gas to heat a 1,500 square foot home whether you paid $50,000 or $400,000 for it. We should view the cost of reliable transportation the same way.

 

airdrie car mechanic

 

 

The magic computer? We still don’t have one.

Thursday, July 20th, 2017

Written by Chris Dekker, former co-owner at Tools in Motion.

 

“Do you have one of those computers that tells you what’s wrong with the car?” This has got to be one of every mechanic’s least favourite questions to get from a customer. As we’ve explained before, while scan tools can provide a starting point for a proper diagnosis, it’s very early in the process that the human brain must take over. As we often tell people, there is a big difference between pulling out a trouble code and actually diagnosing a problem.

Here’s a great example from this week. This little Honda CR-V came to us with a “check engine” light on, and the engine idling rough.

airdrie check engine light

 

We connected a scan tool and retrieved the stored trouble codes from the engine computer, or ECM. As we often see, the stored codes were of no help, as the engine had set misfire codes for all four cylinders. We already knew the engine was misfiring, and the trouble codes don’t tell us why the misfire is happening.

airdrie car scan

 

Even though this vehicle’s rather simplistic engine computer is flagging misfires on all four cylinders, the issue really felt more like a consistent misfire from a single cylinder. Removing and shorting out the spark plugs wires one by one, we determined that the engine was misfiring on cylinder #4.

airdrie spark plugs

 

OK, now what? We’ve got lots of possibilities here: the issue could be a bad spark plug or plug wire; a problem with the distributor (yes, this car still has one); a faulty fuel injector; or about a dozen other things. Removing and inspecting the cylinder #4 spark plug seemed like a good place to start. As it turns out, the spark plug and wire were both in good condition.

airdrie mechanic

 

We noticed, however, that the spark plug was a bit wet with fuel. Having already ensured we had a strong spark supply to the plug from the distributor and coil, this could only mean one thing: The spark plug was firing; the fuel injector was firing; but the combustion event was not taking place inside the cylinder. The next logical step seemed like performing a compression test. We installed our compression tester in the #4 spark plug tube; disabled the ignition system; and cranked the engine over. As it turned out, cylinder #4 was only making about 40PSI of compression! (A good cylinder on this engine measured around 160 PSI.)

airdrie compression test
The low compression was definitely the cause of the misfire. Every engine needs at least 100 PSI per cylinder to “get the fire going”, so to speak. Now it was time to determine why cylinder #4 had low compression. Like before, there are lots of possibilities: it could be a burnt/bent valve; worn out piston rings; or a handful of other things. How do we determine where all that lost compression is going? We install a cylinder leakdown tester. Out came the compression tester, and in went this next tool.

airdrie car repair

 

We rotated the engine until cylinder #4 was on its compression stroke, with all the valves closed. Using the leakdown tester, we filled the cylinder with compressed air. As you can see, this cylinder has about 85% leakdown. (20% is the most we’d ever like to see on a good engine.)

We can also use the leakdown tester to determine where the leaking compression is going, by listening for air leakage at different points on the engine. Air coming out of the intake manifold or throttle body indicates a leaking intake valve on this cylinder. Air hissing from the tailpipe indicates a leaking exhaust valve, and air leaking from the oil cap points towards a leak into the crankcase via worn out cylinders and/or piston rings. This vehicle had none of these leaks. The compressed air was actually leaking from the cylinder #3 spark plug hole, indicating there is a blown head gasket or other combustion leak between these two adjacent cylinders.

The next step in diagnosis will be to remove the cylinder head for inspection, and likely replace the leaking head gasket.

 

Almost every warning light diagnosis works this way. The trouble codes (sometimes) provide a starting point, and then there are usually many other tests that must be performed – using even more specialized equipment – to “zero in” on the route cause of the issue. With some issues, there are no codes stored at all, and the technician must let the symptoms and their experience lead them in the right testing direction.

Every good diagnosis goes like the one on our Honda this week: A well-trained technician knows exactly what test to perform next based on the symptoms at hand, and lets the results of that test tell them what test should be performed afterwards. There is no wasted time troubleshooting parts that don’t need to be checked – and more importantly, no money wasted replacing parts that won’t fix the problem.

This is the value of a good diagnosis by a qualified professional.

Cleaning intake valves, using crushed walnut shells!

Wednesday, October 14th, 2015

Written by Chris Dekker, former co-owner at Tools in Motion.

 

During the 1980s, there was an important shift in the automotive industry: carburetors were out, and fuel injection was in. While a carbureted engine basically sucks in a stream of liquid fuel, a fuel injected engine uses an electronic fuel injector (which is controlled by a computer) to deliver a burst of high-pressure fuel mist at precisely the right moment. Think of a Windex bottle; the stream setting mimics a carburetor, while the mist setting is your fuel injector.

Most fuel injected engines from the last 20 years use port fuel injection, where fuel is injected upstream of the cylinder into the intake manifold. The fuel spray is carried past the intake valve, and into the cylinder (where it is burned) by the flow of air into the cylinder. Remember this part about fuel passing through the intake valve, as it gets important later!

Liquid gasoline has a hard time burning; it’s the vapor that really gets things going inside your engine. The mist delivered by a fuel injector atomizes easier, and burns more completely. This more complete burn – combined with the improved control from having a computer running things – translates into better fuel economy and decreased emissions. Now imagine that we could take that mist from your Windex bottle, crank the pressure way up, and shoot that pressure through tiny holes so small that the human eye can barely see them. The fuel spray would be super fine; how well would that burn?

 

direct injection

This idea is part of a new technology called direct injection. Direct injection also offers another advantage: it delivers its super-high-pressure fuel spray directly into the cylinders of your engine, right beside the spark plugs. Compared to port injection, direct injection offers even better control of the combustion event, and even better performance. Gasoline direct injection (GDI, for short) is getting more common in our industry, as car manufacturers continue to chase better fuel economy and cleaner emissions. GDI can help a small engine to make as much horsepower as significantly larger one, as Ford has demonstrated with their popular Ecoboost engines.

 

airdrie auto diagnostics

 

However, moving the fuel spray from the intake manifold to inside the cylinders had an unexpected conseqeuence: bad deposit build-up on the intake valves. It turns out that the continuous fuel spray onto the intake valves in a port-injected engine did a good job keeping them clean. Deposit build-up on the intake valves of GDI engines has become a big problem; causing misfiring, hard starting and poor performance.

 

carbon buildup valve

This nasty build-up is composed of:

  • Carbon from the combustion of fuel, which is pushed back out of the cylinders.
  • Trace amounts of engine oil that leak past the valve seals, or are carried into the intake manifold by the crankcase ventilation system.
  • Exhaust soot that is recirculated back through the intake manifold by the EGR (an emissions control) system.

 

This all combines to create a rock-hard, clumpy layer of junk on the intake valves that gets thicker and thicker over time. Eventually it builds up to the point where airflow through the valve is restricted, or the valve cannot open and close properly.

The photo above is from a Mazda that we serviced this week, and is the worst example of this build-up that we have seen to date. This engine had less than 150,000 kilometers on it, and a bad misfire that was due in part to the valve issues. With this Mazda, we decided to do a little experiment. As GDI becomes more common in our industry, so too do the problems with intake valve deposits. Several companies have responded with various products designed to clean off these deposits, including CRC with their GDI-specific “Intake Valve Cleaner”. But do any of them work?

Most of these products are a liquid designed to be “fogged” into the intake manifold as the engine runs, where they will travel through the intake valves and hopefully remove some of the deposit build-up as they pass by. The trouble with these products is that you normally never get to see how well they work (or don’t work), since the valves are hidden deep inside the engine. With this Mazda, we had the intake manifold removed and full access to the valves – so we decided to try several popular products to clean the valves directly. We chose CRC Intake Valve Cleaner, Sea Foam Motor Treatment, ACDelco Cleens Combustion Chamber Cleaner, and a last-minute crazy idea: Wipe-Out, a very powerful gun cleaner designed to remove carbon and copper fouling from rifle barrels.

airdrie auto repair

 

First we sprayed each of the valves with one of the cleaning products, let them soak for a couple minutes, then blew out the intake runners with compressed air. Initial results were disappointing: none of these products magically dissolved or removed any of the build-up through contact with the valves alone. Experience told us not to expect this anyways, but it would have been nice!

Next, we tried a longer, ten minute soak and then a good scrubbing with a small toothbrush before blowing out the ports again. A tiny amount of deposit was removed from each valve, with all of the products working about the same, but we were barely making a dent. We could tell that completely cleaning the valves this way would probably take days; not an economical choice for the customer!

It was the end of the day, so we decided to fill each intake port with cleaning product and let the valves soak overnight. The next morning, we gave each valve a good picking-at with a dental pick, and then a scrubbing with the toothbrush before blowing out the ports. The Wipe-Out seemed to work the best, but barely. We were hoping that “thinking outside the box” would produce an industry-leading breakthrough here, but it was not meant to be. All of the products loosened up an outer layer of the build-up, but 80% of the deposits remained.

One important note: Most of these products are designed to work in the presence of heat on a running engine, which should make the carbon build-up easier to remove. This was impossible with the engine disassembled, of course. However, we’d like to believe that if overnight soaking, scrubbing and brushing will not remove much of the build-up, 2-3 minutes of misting onto the valve will not work either.

At this point, it seemed that the various cleaning products, like much of the snake oil bottles on the parts store shelves, were a chemical solution to a mechanical problem, and just weren’t going to work. No chemical was going to remove these deposits, and pulling the cylinder head to remove the valves would cost thousands of dollars. There had to be a better way. It was after a little research that we came across another popular solution: sand-blasting the valves with crushed walnut shells.

 

airdrie car repairs

 

The crushed walnut shells are abrasive enough to remove the deposits, but not enough to remove metal from the valves or cylinder head. After a quick phone call, we had a big 30 pound bag of crushed walnut shells to play with, and decided to try this technique out. Now, we were making progress! It still took a lot of careful work, but the sandblaster did a nice job of cleaning the valves.

The walnut shell grains proved a bit too large for our recovery system to handle, though. A few hours later, poor Richard had walnut shells everywhere – in his hair, his clothes, and even his nose – but the Mazda had some much better looking valves!

 

airdrie auto service

 

The crushed walnut shell technique offers a good value in that it’s much more effective than most cleaning methods, and still relatively quick; definitely the way to go in a case like our Mazda here.

 

Why “A/C in a can” is a bad idea.

Saturday, August 15th, 2015
airdrie auto air conditioning

This is an example of an “auto parts store” A/C recharge kit.

Written by Chris Dekker, former co-owner at Tools in Motion.

 

Air conditioning refrigerant, sometimes referred to as “freon”, is the liquid that circulates through your car’s air conditioning system and makes the system cool. The refrigerant that has been used in vehicles since 1995 is called R-134a. Your refrigerant should theoretically never need topping up or changing, but the reality is that it can sometimes leak out over time, and your vehicle’s air conditioning may start to work poorly. (If a leak is found, it should be repaired, of course!) This post explains why an increasingly popular air conditioning “solution” is actually a bad idea.

While browsing your department store, you may have come across small cans of aftermarket, hydrocarbon-based refrigerant for sale, including brands like Duracool, Red Tek, and Emzone 12A. Should you use these products to “top up” your air conditioning system, and get it cooling well again? These products claim to offer better cooling (because they are a more efficient refrigerant), and be easier on the environment, so it sounds tempting. They’re cheap, too. While these claims are partially true, there are a bunch of reasons why you still shouldn’t put them in your vehicle’s A/C system:

 

Reason #1: You can’t recharge your system properly.

A proper, long-lasting air conditioning recharge procedure includes the following steps:

  1. Evacuate the old refrigerant from the system, and weight it to determine if the system was over, or under-charged.
  2. Measure the amount of oil that was removed from the system.
  3. Using an electric vacuum pump, pull a vacuum on the system for at least 15 minutes to draw out any trapped air, and boil off any water in the system. (Water boils at room temperature when under a vacuum!)
  4. Leave the system under vacuum for at least 10 minutes after stopping the pump, and monitor rate of vacuum drop to test the system for leaks.
  5. Add the appropriate amount of oil to the system. There is a minimum amount of oil required to protect system components; but too much oil will insulate the lines and reduce cooling.
  6. Charge the system with a specific weight of refrigerant. Too little refrigerant will result in poor cooling, and too much will create high running pressures, also causing poor cooling.
  7. Run the system and monitor high and low side pressures; temperatures; cooling fans, etc, to make sure everything is working properly.
  8. Add an ultraviolet dye to the system, so if any leaks develop, they can be located with a UV light and glasses.

The “refrigerant in a can” kits only address step #6, and poorly at that. There is no way to accurately measure how much refrigerant is added, and no way to pull all the air out of the system before adding it.  This means you are injecting an unknown amount of one refrigerant on top of an unknown amount of a different refrigerant (plus any air and water in the system), with an unknown amount of oil. It’s not hard to see why the results are often less than stellar.

So what happens if you try a hydrocarbon-based refrigerant, and your A/C still doesn’t perform as desired? Maybe now, it’s time to bring your car to a professional. But that brings us to problem #2…

 

Reason #2: Once a hydrocarbon-based refrigerant is added, most professional mechanics will not touch your A/C system.

What’s an azeotrope? It’s a mixture of  two different refrigerants, which when mixed, exhibit unique and undesirable properties. By adding a hydrocarbon-based refrigerant to the haloalkane factory refrigerant, this is what you create. This mixtures of refrigerant often behave unpredictably, and don’t function right in an A/C system.

Azeotropes cannot be disposed of in the same way that you could with a pure refrigerant such as R-134a. In Alberta, azeotropes are treated as a hazardous waste and must be disposed of at the Swan Hills treatment facility, at a cost of over $300 per pound. You can see why no shop would want to contaminate their R-134a tanks, or their A/C equipment with a hydrocarbon-based refrigerant!

We (and most other businesses) use an expensive tool called a refrigerant identifier, before we hook equipment up to your A/C system. It lets us take a sample of the refrigerant in your system, and analyze it to find out what chemicals it’s made up of. If we find hydrocarbons in the system, we have to inform the customer that we cannot service their air conditioning.

 

airdrie auto ac

Here is our refrigerant identifier, taking a sample on a customer’s vehicle. This is a $3000 tool!

 

Reason #3: Hydrocarbon refrigerants are flammable.

That’s right! Most of these “canned” refrigerants are made up of a light hydrocarbon such as propane. Propane actually has the right boiling point to make an excellent refrigerant, if it wasn’t for the safety concerns involved. In the event of a front-end collision where the air conditioning condenser or hoses were punctured, high pressure refrigerant spraying out at over 100 PSI could cause an inferno in a matter of seconds if it comes in contact with something hot under the hood. The chances are low, but this situation is certainly possible, and does happen. Refrigerant vapour under the hood can even be ignited by a leaking spark plug wire.

 

The “A/C in a can” solution is tempting for somebody who doesn’t know better: it’s quick, easy and cheap – but as you may now understand – could end up costing you a whole lot more than just servicing your system properly in the first place.

Explaining the Diagnostic Process

Sunday, October 12th, 2014

Airdrie Automotive Diagnostics

Written by Chris Dekker, former co-owner at Tools in Motion.

 

The other day, a customer called us to ask if we had “one of those computers that tells you what’s wrong with the cars”. I was tempted to make a goofy response like “Yes, and I have robots that fix them for me, too!”, but I knew what they meant. The customer was talking about a scan tool. And of course, we do have scan tools; four different ones, in fact.

Scan tools have been around for decades and became a very necessary tool in the 1980s as vehicles switched from carburetors to fuel injection, which of course meant they now had an on-board engine computer. Today’s vehicles have between 5 and 50 on-board computers; the scan tool is a device that lets a qualified technician communicate with these on-board computers in order to diagnose problems, test systems, and make software changes. Today’s scan tools – many of which aren’t actually “tools” anymore, but laptop-based programs – are pretty advanced. That being said, most customers don’t realize how little the scan tool actually contributes to an accurate diagnosis, and how quickly in the process the human brain must take over from the tool.

One of the more regular things that we use a scan tool for is to diagnose a warning light, such as a Check Engine or ABS light. Whenever a warning light comes on, this means that an on-board computer has detected some sort of problem, and stored a “trouble code” as a result.  In the case of the Check Engine light, these codes read something like P0302 or P0171. Any code starting with P0- is universal between most vehicles, so the scan tool will usually add a definition so they read P0302 – Cylinder #2 Misfire and P0171 – Fuel System Lean, Bank 1.  Retrieving these trouble codes from the vehicle is usually a quick process, and this is where two common customer misconceptions (and sometimes, sources of frustration) come from:

  1. Because the code retrieval process (which is only the start of the diagnosis, as we’ll get to in point #2) is so quick, customers sometimes feel ripped off when they are charged $100-150 for this service. This is partially our fault, as most shops will show the service as a one hour charge on the invoice. If the service doesn’t take this long, it’s only natural for customers to get upset. It’s very important for us to explain that we’re billing customers for a $120 charge vs one hour’s labour. This might be the same dollar amount, but we need to justify the charge for what it really is: in part, a way to earn back the purchase cost of the scan tools being used. In total, our four scan tools cost over $25,000 and require another $3500 in software updates every year.
  2. Many customers also don’t realize that retrieving a trouble code is only part of properly diagnosing an issue. This is partially because we as professionals haven’t done a good enough job educating consumers; parts stores that will “pull a code for free and then sell you a part” aren’t helping the situation. For example, what’s causing that P0302 – Cylinder #2 Misfire? Is is a spark plug? A plug wire? It could also be an ignition coil, a fuel injector, a wiring problem, a bad sensor, a vacuum leak – even a mechanical condition such as low compression on that cylinder, a sticking valve, or broken valve spring. This is where a properly trained technician – and a whole bunch more test equipment – are required to narrow in on the real problem.

 

Here are some of the steps a properly trained technician will take in order to diagnose most Check Engine lights, once the easy part (pulling the code) is complete:

  • Using the scan tool, monitoring the PIDs (or parameter IDs) for the affected module. These are hundreds of numbers that the scan tool spits out in real time, constantly updating them many times per second. These can be temperature readings, voltages, duty cycle (on/off time) numbers, resistance values and more; and they have confusing names like B1S2 Ho2S, VGT DUTY % and VREF, etc:
    Airdrie Auto Diagnostic Numbers

    Some basic engine PIDs being graphed

    None of these numbers really tell you anything by themselves; it takes a skilled technician to know which ones are relevant to the problem being experienced, and to understand the relationship between these numbers. (When number A increases, number B should increase at the same rate, while number C decreases at half that rate, etc.) Interpreting all of these numbers will help the technician understand what’s going on inside the engine, and narrow on on which part of the engine is having trouble.

  • The technician will likely also consult published service information from the vehicle’s manufacturer – which we subscribe to – in order to familiarize themselves with how certain systems work, what readings to expect, etc. It’s impossible to remember everything about every single vehicle on the road, which makes the tech’s ability to understand service information, diagrams and wiring schematics very important. These service information subscriptions aren’t cheap, either – but like the scan tools, are a very necessary part of a shop’s tools and equipment budget.
  • The tech will probably also check for Technical Service Bulletins (TSBs). These bulletins, released from the auto manufacturers to service facilities like ours, serve to alert us to common issues we should know about. They may also contain information on updated test procedures, updated fluid recommendations, new specialty tools that have been released for a given repair, revised/improved parts that are available to fix certain issues, and more. A quick check of the TSBs will help the technician ensure they aren’t missing any important information that they need to diagnose an issue accurately and carry out a proper repair that lasts as long as possible.

At this point, the technician has probably exhausted all of the information that the scan tool, and their computer, can give them. Finalizing the diagnosis will probably require some hands-on testing with a variety of other tools. Sticking with the P0302 – Cylinder #2 Misfire, the tech may use:

  • An ohmmeter and spark tester to check the spark plug wires and ignition coil.
  • A fuel pressure tester and injector pulser/balance tester, used together to test the fuel injector flow rates.
  • A multimeter, test light, noid light, oscilloscope or other tools to check for wiring issues associated with the sensors, ignition coils and fuel injectors.
  • A vacuum pump, vacuum gauge or smoke machine to rule out the possibility of vacuum leaks.
  • An exhaust backpressure gauge, or pressure transducer to check the engine’s air pumping action and rule out a restricted exhaust system.
  • A compression tester, cylinder leakage tester or borescope to check for internal, mechanical engine problems.

Depending on the situation, there may be more – or less –  tests and tools required, of course. We feel that all of the additional work that comes after “pulling the code” is part of the proper, complete diagnosis, and it’s included whenever you pay us to diagnose a warning light on your vehicle. We hope this insight into what we do every day will help our customers recognize the value in the diagnostic charges that they are billed for. After all, by the time we’re done, we should be able to tell you exactly what your vehicle needs without any guesswork. It’s what we’re known for, and our reputation depends on it!

Understanding Tire Sizes

Friday, May 9th, 2014

Written by Chris Dekker, former co-owner at Tools in Motion.

 

We get a lot of questions about tires, and tire sizing, which is no surprise because the sizing format that has become the industry standard couldn’t be more confusing. What do all those numbers on the sidewall of your tire mean? Let’s break it down:

 

Airdrie Tires

 

  • The section width is pretty straightforward. This is the width of the tire, in millimeters.
  • The aspect ratio is where things start to get confusing. This is the height of the tire sidewall (from rim to tread), but this is expressed as a percentage of the width. For example, this tire’s sidewall height is 75% of 185mm, which is a little under 140mm. Because the aspect ratio is a percentage, a 195/75R14 tire is actually wider and taller than say, a 185/75R14 tire.
  • The “R” construction method means this is a radial tire, as with almost every tire produced today.
  • The rim diameter is expressed in inches – yes, we’re mixing metric and imperial measurements here for some reason! This tells us what diameter of rim this tire will fit on.

These measurements all often all that is considered when most customers shop for tires, but there are two more very important numbers on the side of your tires that shouldn’t be overlooked:

  • The load rating tells us how much weight the tire can support at its maximum air pressure without failing. For obvious reasons, your tire’s load rating should meet or exceed what is required by your vehicle.
  • The speed rating of the tire is often misunderstood. In theory, this number tells us how fast a tire can be driven without failing, but even cheap “S” rated tires are rated for 180 kilometers per hour! The ratings continue to increase as you move towards the end of the alphabet.

So, why not just put “S” rated tires on every vehicle? You’re not going to drive that fast, right? In reality, the speed rating tells us a lot more about the construction and stiffness of the tire – how it brakes, corners and grips – even how much it heats up travelling down the road. It is absolutely essential that your tire speed rating meets the standard required by your vehicle in order for it to handle and perform the way the manufacturer intended.

Recently, Global News showed a story where they equipped two Mazda sedans with new tires; one with the recommended “V” rated tires, and one with cheaper “S” rated tires. Not only did the car with the right tires ride and handle better, it also stopped a whopping 23 feet sooner when both vehicles had to brake hard from 80 km/h. This could be the difference between life and death in some situations.

 

Airdrie Tire Shop

 

Most newer vehicles have a tire size placard, similar to the one above, which will show you what size (plus load and speed rating) of tires your vehicle requires. It will also show you the manufacturer’s recommended tire pressure. A quick note on this: Always set your tire pressures to the recommendation on this decal. The tire pressure shown on the sidewall is the theoretical “maximum pressure” of the tire, and may be way too high for your vehicle!