Cummins Injectors & Nozzles — part numbers

Injectors and nozzles are the highest-value consumable on most of the engines we supply, and the category where buying decisions go wrong most expensively. 247 numbers are catalogued here, spanning PT injectors for the mechanical KTA and 855 families, common-rail injectors for the ISM, ISX, QSX and QSK engines, and the nozzle assemblies, cups and holders that go with them.

The single most useful thing to know before ordering is that injector part numbers are calibration-specific, not engine-specific. Two KTA50s of the same model year with different CPL numbers can take different injectors, and fitting the wrong calibration will not throw an obvious fault — it will run, make slightly the wrong power, and load the cylinders unevenly. Send the CPL or the ECM calibration with the enquiry and this problem disappears.

On tier, this category divides sharply. For common-rail injectors on electronic engines we quote genuine by default, because the tolerances involved are not something the aftermarket reliably matches and because a marginal injector on a high-pressure system damages more than itself. For PT injectors on the older mechanical families there is credible remanufactured and branded aftermarket product, and we will quote it openly alongside the genuine part so you can see both numbers.

Counterfeit injectors are a real and current problem in this market. They are visually convincing, they are sold as genuine, and they typically fail between three and nine months in. Every injector we supply is stated as Tier 1 with documentation available on request, or stated as Tier 2 with the manufacturer named. There is no third option on our quotations.

If your enquiry follows a failure rather than a service interval, tell us what the engine was doing when it failed and what the fuel filtration history looks like. Injectors that fail early usually failed because of something upstream, and replacing them without addressing it means doing this again.