This is the Alliant Power AP50904, a common-rail fuel injector remanufactured by Alliant Power for the John Deere 8.1L PowerTech 6081 six-cylinder engine. Catalog fitment that two sources agree on includes the 8320 tractor and the 9660 STS combine. A refundable core applies.

The 8.1L engine used four different common-rail injectors over its run, and Alliant Power sells each under its own number: AP50902, AP50903, AP50904 and AP50905. They look alike on the bench and carry different John Deere numbers, so order by engine serial number and the number on your old injector, not by machine model alone. Hard starting, a miss under load, rough idle, white or black smoke, fuel in the oil or a cylinder balance fault are the usual reasons these come out. Check fuel filters and rail pressure before you condemn a set.

Specifications

Fits / Applications

• John Deere 8.1L PowerTech 6081 six-cylinder engines with common-rail injection
• John Deere 8320 tractor
• John Deere 9660 STS combine
• Fitment splits by engine serial number. Call with the serial number before you order.
• Six injectors per engine

Fit new sealing parts, keep every open fuel connection capped until it is made up, and change the fuel filters at the same time. Common-rail injectors do not tolerate dirt or water.

Part Numbers & Cross Reference

Alliant Power AP50904  ·  Alliant Power sister injector, same engine family (not interchangeable) AP50902  ·  Alliant Power sister injector, same engine family (not interchangeable) AP50903  ·  Alliant Power sister injector, same engine family (not interchangeable) AP50905

Cross-reference numbers can change with engine serial, build year and emissions tier, so treat this list as a starting point. Send us your engine serial number and we will confirm the exact match against your build before anything ships. That check is free and takes a few minutes.

Frequently Asked Questions

Will the AP50904 fit my John Deere 8.1L engine?

It is built for the 8.1L PowerTech 6081, and catalogs agree on the 8320 tractor and the 9660 STS combine. The same machine can take a different injector depending on the engine serial number, so call 530-668-0818 with the serial number first.

What is the difference between the AP50904 and the AP50902?

Both are Alliant Power remanufactured common-rail injectors for the John Deere 8.1L, but they replace different John Deere injector numbers and cover different engine serial ranges. Match by the number on your old injector.

Is it new or remanufactured, and is there a core?

It is remanufactured by Alliant Power. A refundable core applies, and it comes back when we receive your old injector.

What do you need from me to confirm the right injector?

The engine serial number from the engine plate, the machine model, and the John Deere and Denso numbers on the old injector body. With those we can match the correct Alliant Power number.

Related Parts

• John Deere 8.1L PowerTech 6081 Common-Rail Fuel Injector | Alliant Power AP50902 Remanufactured
• John Deere 8.1L PowerTech 6081 Common-Rail Fuel Injector | Alliant Power AP50903 Remanufactured
• John Deere 8.1L PowerTech 6081 Common-Rail Fuel Injector | Alliant Power AP50905 Remanufactured
• John Deere 4045 4.5L & 6068 6.8L Common-Rail Fuel Injector | Alliant Power AP52907 Remanufactured

Why Buy From Valley Fuel Injection

We are a diesel fuel-injection and turbocharger shop in Woodland, CA, rebuilding pumps, injectors and turbos on our own benches since 1993, not a drop-ship storefront. When you call, you talk to the people who test these units. We verify fitment against your engine serial, VIN or build date before anything ships, so the right part arrives the first time.

Not sure the injectors are the problem? We test and diagnose in-house before you buy. See our common rail injector testing and rebuild service.