icon-phone 619.235.0961    icon-email Email

When Downtime Is Not An Option.



Guide to 6.6l Duramax Fuel Injector Repair, Replacement and Common Issues

Guide to 6.6l Duramax Fuel Injector Repair, Replacement and Common Issues

When it was released back in 2001, the 6.6L Duramax engine was considered the apogee of diesel engine design. The fact that the original design has not changed, but has only been improved upon, speaks for itself. However, before all the modifications the later models were equipped with, Duramax was not problem-free.

In our previous article, we’ve talked about some of the most common issues early models suffered from. And most of those issues had one word in common: injectors. Injectors for 6.6l Duramax diesel, especially in its earlier incarnations, had a bad habit of failing before the engine reached a certain mileage.

A failing injector can cause a number of problems, most commonly leaking fuel into the engine. As these injectors were often very expensive and difficult to repair, the manufacturer was forced to extend the warranty and improve the design.

Common Issues Injectors for 6.6l Duramax Diesel Suffer From

As previously mentioned, injector failure was a particular problem with models manufactured between 2001 and 2004. Because of this common issue, GM had to fix the problem by offering a better design as well as extending the warranty mileage, now sitting at 200,000 miles or 7 years.

Those buying a used vehicle have to be aware that not all engines have been equipped with the improved design. Buying an older model you risk being put in a very uncomfortable position down the road and being forced to search the web for 6.6l Duramax engine for sale if the problem is not fixed in time. This inherit flaw seems to have been fixed in all the models issued after 2004, but Duramax injectors are still known to be very sensitive to contamination and tend to fail if not subjected to regular maintenance.

Another issue closely related to the injectors occurs when the harness holding the wiring together chafes. This can cause a number of problems, from the engine failing to start to experiencing difficulties when running or experiencing power shortage. To fix this issue, you will have to replace or repair the harness, depending on how severe the damage is.

Diagnose the Issue before moving to 6.6l Duramax Injectors Replacement

Diagnosing the issue with injectors for 6.6l Duramax diesel can be a challenging task for those with no experience. A professional will be able to diagnose the issue by checking the balance rates. An expert repair shop will have all the necessary tools for such a task.

6.6l Duramax replacement instructions: Crucial Points

The same thing goes for replacing or repairing the injectors. Most often, the 6.6l Duramax replacement instructions you find on the internet are not good enough, and can cause you to make matters worse through improper handling.

We will try to explain the core process. If you are unfamiliar with the mentioned parts, it may be better to contact an expert and have the issue resolved for you.

In short, the first thing you should pay attention to is finding the drain valve and draining the coolant. The first step is also crucial, as it helps prevent the coolant from flooding into the combustion chamber when removing the injectors. As you are draining the coolant, make sure to disconnect the battery to avoid damage to any modules.

Afterwards, remove the A/C condenser, the water thermostat and the neck of the coolant. If your thermostats need replacing too, this would be the perfect time. Next remove the Fuel Injection Control Module and the Glow Plug Harness. Cut the fuel line with a proper tool and remove the fuel injector keys.

Remove the fuel lines on the engine and let the liquid that was still in the lines drain. Next, remove the fuel injector harness and the lower valve cover. Do not rush these few steps in order to avoid damaging the engine.

After removing the valve cover, proceed to removing the fuel return lines. You’ve finally found the injectors. You will need to remove them by removing the bolt from the injector hold-down. Pry the Injector hold-down open with a prying bar, available at any local parts shop or hardware store. Replace the injector cup with a new one and you have a brand new injector, ready to roll out.
  1. Make Contact
Please enter a name.
Please enter a valid email address.
Please enter a valid phone number.
Invalid Input
Invalid Input
I Would Like More Information About:

Invalid Input
Send me your newsletter:

Invalid Input

Our Guarantee

At PCE, we pledge to provide you with the highest level of integrity and expertise; to recommend only what’s good for you and your situation; to use all resources possible to minimize downtime; to give the best value for your dollar; and to stand by our work and our word.

Contact Us

Corporate Headquarters
1620 Rigel Street
San Diego, CA 92113
Phone: (619) 235-0961
Fax: (619) 233-5096 
Diesel & Motor Division
3376 Main Street
San Diego, CA 92113
Phone: (619) 235-0961
Fax: (619) 687-0038 
99-1221 Halawa Valley Street
Aiea, HI 96701-3281
Phone: (808) 486-6600
Fax: (808) 845-1652 
920 West Marine View Drive
Everett, WA 98201-1300
Phone: (425) 257-9065
Fax: (425) 259-6851