How To: Diesel Injector Installation, Cummins ISX

Odds are, at some point in the life of your diesel engine you'll need to remove or replace your fuel injectors. But do you know the right way to do this? Master Diesel Mechanic Mike Schrems talked us through how to install diesel fuel injectors in your ISX engine.

HHP has a large selection of injectorsif you're looking for an ISX injector, check out our article on the products we offer.

For an in-depth look at installing an ISX injector, take a look at our video.




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Installing Your Injectors

The install pictured below and featured in the video was done on an ISX 871. The exact guidelines for you will depend on which engine you're running. Refer to your manual for more information. If you want to know more about the ISX, we have a blog dedicated to it!

    1. We began the installation with the injector out of the cylinder head. At this point, you'd have already done your repair, whether that was replacing a head gasket, or doing an in-frame overhaul. If you're doing an engine rebuild on your ISX, we have some tips for you!


    1. If you're reusing your injectors, you'll want to replace the o-rings. These o-rings come in the overhaul kit or the upper gasket set. These o-rings are different sizes, so you want to make sure that you get the right o-ring in the right groove to ensure a proper fit. An o-ring hook can really help make this a little easier.


    1. Next, you want to clean out the bore of the injector hole. In the pictures, we have the rocker shafts removed so that you can see how this is done.  isx-injector-install-a


    1. Once the injector bore has been cleaned with a brush, you might want to take a shop towel, place it on the brush, and use it to clean any soot or debris left in the bore. The shop towel will pick all that up, further cleaning the bore. 
      • It's not recommended that you blow into the bore of the injector hole, because you may unintentionally force debris into the combustion chamber, which would not be good.


    1. Next, get your injector and lube the o-rings with engine oil before you put the injector hold down in, so that the bolt hole where the injector hold down goes is free of oil or debris. This prevents it from achieving torque before it is actually tight.


    1. Carefully align the injector in the injector bore. 


    1. Place the hold down over the injector and start the cap screw. These particular injectors get torqued to 59 foot-pounds, if you look it up on Quick Serve online, or if you have a shop manual for the ISX engine. Make sure you look for the right vintage engine. As we mentioned, this install was completed on an 871. The injector hold down actually pulls the injector down into the bore. 


  1. After the injector is in the cylinder head and properly torqued, you would want to install the rocker shaft assemblies and go through and set the valve injector settings.


If you've already installed your injectors and are looking for information on how to ensure they're timed properly, read our blog on the topic!

Interested in the ISX engine? We have the lowdown on common problems and failures!

Do you have lingering questions about your injectors? Call our certified techs at 844-304-7688 to learn more. Or request a quote online!

Edited August 16, 2019