Chevy EcoTec3 5.3L Engine Problems
After a strong 30+ year run for the Chevy Vortec engine family, the Vortec was replaced with the new EcoTec3 engine line. Plagued by oil consumption issues and active fuel management problems, the Vortec engines were retired in 2013. Introduced in 2014 the EcoTec3 engine family featured 4.3L, 5.3L, and 6.2L engine variations throughout the Silverado, Sierra, Yukon, Corvette, Suburban, and CTS-V vehicles.
The 5.3L EcoTec3 engine is a small-block V8 engine, similar to its Vortec 5300 predecessor. The engine was produced in 4 different variations, the L83, L8B, L82, and L84.
L83 EcoTec3 5.3L
2014-2019 Chevy Silverado and GMC Sierra
2014-Present Chevy Tahoe and GMC Yukon
2014-Present Chevy Suburban and GMC Yukon XL
L8B EcoTec 5.3L
The L8B engine variation was a semi-hybrid engine variation that featured a lithium ion battery pack for fuel efficiency. It was only used from 2016-2018 in select Silverado’s and Sierra’s.
2016-2018 Chevy Silverado and GMC Sierra
L82 and L84 Variations
The L82 and L84 variations of the EcoTec3 5.3L were available only in 2019 or newer Silverado and Sierra’s. The L82 system uses active fuel management and was only available on low-level trims while the L84 engine uses dynamic fuel management and was only available for high-trim vehicles.
5 Most Common Chevy EcoTec3 5.3L Engine Problems
- Carbon build-up
- Fuel injector failure
- 4WD transfer case sensor failure
- Fuel level sensor failure
- Active fuel management – is it still a problem?
1. EcoTec3 Carbon Build-up
One key difference between the Vortec and EcoTec3 engine families is fueling. While the Vortec engines used port-injection the EcoTec3 engines were built with direct fuel injection. With port-injection, gasoline is injected into the intake ports where it then travels to the cylinders. Fuel is highly pressurized when it is injected, so the intake ports have a flow of high-pressure gasoline running them through to keep them clean of any gunk or build-up.
On direct injection engines, the fuel is injected directly into the cylinders, completely bypassing the intake ports. Because the intake ports are bypassed, there is no high-pressure fuel flow to keep them clean and gunk free. This results in a build-up of gunk or sludge as a byproduct of oil and fuel burn that lines the intake ports. Carbon buildup can have noticeable performance implications as excess buildup decreases the volume of air that the intake ports can hold, resulting in the engine not getting enough oxygen.
Symptoms of EcoTec3 Carbon Buildup
- Rough idling, stuttering at idle
- Decreased power and shaky acceleration
- Engine misfires
- Slightly lean AFR ratios
On the 5.3L EcoTec3, you will probably start to notice some carbon buildup effects around the 70,000-80,000 mile range. The only true way to fix this is to regularly clean the intake ports by removing the manifold and walnut blasting or pipe cleaning the valves. However, there are a few things you can do regularly to decrease the effects of carbon buildup. Option one is to install an oil catch can, which collects any used oil and prevents it from re-entering the engine and building up on the valves. Secondly, you can purchase some GDI intake valve cleaner and spray it into the intake system (after the MAF sensor) every 5,000 or so miles. Neither of these options will completely solve the carbon buildup issues, but it will prevent buildup and prolong the amount of time until you need to do a full valve cleaning.
2. Fuel Injector Failure – 5.3L EcoTec3
Fuel injectors are the key component of direct injection. They sit within the engine block and spray the gasoline directly into the cylinder at extremely high pressures. Fuel injectors spray gas at nearly 1,500+ psi of pressure, which means they are naturally subject to a lot of stress. Additionally, they are exposed to very high temperatures which can lead to issues over time through normal wear and tear.
Due to the high heat and extreme pressure, injectors usually wear out over time. They can become gunked up, begin leaking, loose pressure, or simply completely fail. On the EcoTec3 5.3L engine, the injectors are mostly known to completely fail. When an injector fails, it either fails in an open or a closed position. When an injector fails open it sprays too much gasoline into the engine, and vice versa when it fails closed. On these engines, they commonly fail closed which results in no gasoline entering the cylinder with the failed injector.
Each cylinder has its own injector, but they do at least tend to fail one at a time, rather than all at once. Bad injectors will certainly limit the driveability of your car and will have some very notice performance effects.
EcoTec3 Fuel Injector Failure Symptoms
- Cylinder misfires (most common sign)
- Rough idling, poor acceleration, loss of power
- Check engine light with engine misfire codes
- Air-to-fuel ratios are either running rich or lean
The easiest way to tell that you have an injector problem is through the check engine light and engine codes for misfires. You will get cylinder-specific misfire codes which will point you in the direction of the bad injector. It’s worth noting that bad spark plugs and ignition coils can also cause engine misfires, so you might want to check these things prior to replacing an injector as injectors tend to be more expensive and difficult to replace.
3. 4WD Transfer Case Sensor Failure
Transfer case issues on the 4×4 Chevy’s and GMC’s go back to the 1990’s. Unfortunately, transfer case sensor failure has been reportedly somewhat commonly on all cars with the EcoTec3 engine. While this sensor isn’t necessarily engine related, it’s common enough in 2014-present models that it’s worth mentioning.
The transfer case is responsible for transferring powering from the engine to the front and rear wheels, through the driveshaft. On vehicles where you have 4×4 and rear-wheel drive options, there is a transfer case sensor that is responsible for controlling whether the truck is in 2-wheel or 4-wheel drive mode. When the sensor fails, the truck can get stuck in or out of 4×4 mode. Additionally, it is common for the truck to shift itself in and out of 4×4 without your control. This can lead to difficulty shifting gears, and noises from the transmission of the truck.
Symptoms of 4WD Transfer Case Sensor Failure
- Truck is stuck in 4×4, or won’t go into 4×4
- 4WD Service light appears on dash
- Noisy shifting gears, or difficult to shift gears
- 4WD light flashes on and off intermittently
Fortunately, the repair here is as simple as replacing the transfer case sensor which is a rather inexpensive job. We recommend fixing this issue when it arises as continuing to drive can cause drivetrain issues if your car is frequently trying to switch in and out of 4WD while it’s moving.
4. EcoTec3 Fuel Pump Failure
Engines that use direct injection, such as the EcoTec3, actually have two fuel pumps. A low-pressure fuel pump and a high-pressure fuel pump, or LPFP and HPFP. High-pressure fuel pumps are common failure points on virtually all direct injection engines. The HPFP is responsible for delivering the highly pressurized fuel to the fuel injectors.
These high-pressure pumps are also extremely stressed due to the heat and pressure they operate under. Over time it is common for the internal components to wear out and cause the pump to fail. Likelihood of HPFP failure is increased on trucks that are tuned, driven aggressively, or have performance modifications. The more horsepower your truck makes, the more fuel it needs to feed the engine. Therefore, the harder the HPFP has to work to deliver that fuel.
Fuel Pump Failure Symptoms – EcoTec3
- Long crank times
- Engine won’t start
- Engine malfunction light appears or service engine light
- Reduced power and performance
5. EcoTec3 and Active Fuel Management Problems
One of the biggest issue with the 5.3L vortec, and really all vortec engines for that matter, was excessive oil consumption caused by the active fuel management system. The AFM system issues are one of the big reasons that GM transitioned to the new EcoTec3 engine family. AFM, also known as cylinder deactivation is where the engine shuts off 50% of the cylinders under certain driving conditions in order to improve fuel efficiency.
On the 5.3L V8, 4 of the cylinders are shut off, essentially making your truck a V4. I’ll stay away from the backstory of why the AFM is problematic, as there are dozens of theories and GM itself has never really been able to 100% pinpoint the issue. However, the AFM system is known to cause excessive oil consumption issues. In addition to excessive oil consumption, the AFM can also cause the lifters to fail on the EcoTec3 engines, which is a rather expensive fix. AFM is good for maybe 10-15% improved fuel economy, but really isn’t worth it for all the potential problems it can create.
Is AFM still an issue?
While everyone hoped the EcoTec3 engine would fix the AFM issues, they still appear to be common. However, I would note that they appear to be somewhat less common that they were on the previous Gen III and IV vortec engines. Although this might be due to the fact that these engines are newer and less people are reporting problems as their cars likely still have factory warranty. The short answer is yes, the EcoTec3 engines still have AFM issues.
Guide to disabling AFM: https://chevytrucks.org/delete-or-disable-active-fuel-management/