An Injection of Opportunity

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Direct-injected engines, while more efficient than their port-injected counterparts, also have their own set of issues. PHOTO General Motors

Why do GDI education and proper maintenance benefit both shops and motorists?

You’ve probably heard the scenario. A customer is driving their SUV one day and the engine dies. Initially, it might seem like a fuel problem, but closer examination reveals complete engine failure. The kicker? The vehicle had less than 48,000 km on it. It might be under the manufacturer’s powertrain warranty, so an authorized dealer installs a replacement engine and the same thing happens again after another 48,000 km. By this time, the vehicle is out of warranty and the customer is facing a huge repair bill or having to trade their now essentially worthless vehicle in on a new one.

So, what’s the issue? Well, the vehicle in question was equipped with a direct-injected four-cylinder engine and nobody bothered to explain to the customer the specific maintenance requirements for that engine. As a result, the oil wasn’t changed at the proper interval, the right spec of oil wasn’t used and the PCV system wasn’t regularly inspected and serviced.

Carbon deposits

On a GDI engine, because fuel is injected directly into the cylinders, during certain operating conditions, such as stop and go traffic, carbon starts to build upon the valves, since because the injectors are mounted behind the intake valves and not in front of them like on a port injection setup, fuel cannot wash over the valves to remove deposits and lower the temperature.

As a result, the valves tend to run much hotter and as the carbon builds up, it hardens, creating an insulation effect and not allowing the valves to cool. The valve heads eventually snap off, causing the valve to drop down into the cylinder, breaking the spark plug and damaging the piston, causing engine failure.

Additionally, because some GDI engines don’t have adequate crankcase ventilation, oil can get drawn in through the intake manifold and into the combustion chamber. When oil mixes with fuel it can, when combined with carbon deposits, result in a smouldering effect inside the chamber. As a result, when the driver of the vehicle accelerates, forcing more fuel and air in, the result can cause pre-ignition, particularly on engines that also rely on forced induction (turbocharging).

While OEMs have taken steps to reduce the risk of this issue, modifying combustion chamber design and in some cases—like Toyota–combining port and direct injection systems, there are still large numbers of older, GDI equipped vehicles in circulation whose owners might not be aware of the potential problems lurking beneath their hood.

Inform and educate

As a result, aftermarket service providers have an opportunity to both educate and assist the owners of these types of vehicles. According to Rob Ingram, who owns and operates Eldon Ingram NAPA AUTO PRO in Stratford, Ont., education is crucial. Ingram says that as the issue of low-speed pre-ignition (LSPI) in GDI engines became a growing concern, his team took a proactive approach to educating their clients. This included posting displays of valves on a GDI engine before and after cleaning to demonstrate why a GDI cleaning procedure was necessary.

“We asked them whether they knew their vehicle was equipped with GDI and if they have had this service performed,” he says. If the customer didn’t understand the service, the shop would present them with two options, one for disassembling the top end of the engine and blasting the valves with walnut shell media or performing a preventive flush by running an additive through the engine every 40,000 km, at less than half the price of the first option.

Ingram says that it presented his business with another service opportunity to get paid for real, legitimate work, as well as building confidence with the shop’s client base. In situations like this, he says it’s important for service providers to “identify the requirement, promote it and inform and educate. “Once you have,” he says, “then away you go.”

A significant part of preventing potentially catastrophic issues on GDI engines also comes down to service intervals and the type of lubricants and filters used. A big issue with many GDI engine failures is that the customer was not educated on using the right spec oil or filter. As Albert Côté-Séguin, National Key Account Manager, PCMO Marketing & Services at TotalEnergies Marketing Canada, notes, “engine lubrication can play a role in the mitigation of a phenomenon [like LSPI]. Newer engine oils that meet the API SP and ILSAC GF-6A international standards are blended to meet stringent engine tests to limit such occurrences.”

Usage matters

Regular service intervals are also key and should not only be hinged on the OEM requirements but also how the vehicle is used. With issues such as LSPI tending to impact smaller-displacement turbocharged GDI engines, Rob Ingram says that many of these vehicles shouldn’t be used for towing or hauling, which place additional stress on the drivetrain and exacerbate the potential problems.

Like Côté-Séguin, he also stresses that when it comes to maintenance, it’s important to educate customers that they aren’t saving money by opting for lower-quality lubricants. “OEMs and lubricant manufacturers spend millions in developing the right oils for the right application,” he says, plus given that today’s engines are built to such tight tolerances and are subject to higher cylinder pressures, “you simply can’t afford to mess around.”


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