This is the Alliant Power AP66921, a remanufactured G2.9 fuel injector for the 2007 to 2010 International MaxxForce 9 (300 to 330 hp) and MaxxForce 10 (310 to 350 hp), the 9.3L (570 cu in) inline sixes that took over from the DT570 family in 2007. It covers engine serial numbers 3,000,001 through 3,300,000. It is remanufactured by PurePower Technologies (PPT), the original-equipment supplier of the G2.9 to Navistar, and sold under the Alliant Power name. Each one gets a new coil, coil harness, connector and spool valve. It replaces Navistar 1848721C92, 1848721C93, 4307212R91 and 5010823R91, and it comes with the chamber gasket fitted and its injector seal rings.

A miss or rough running, hard starting, low power and a check engine light with injector circuit codes are the usual reasons these come out. The G2.9 is fired by high-pressure engine oil, so a leaking oil rail seal, a weak high-pressure oil pump, low or dirty oil, or a damaged harness under the valve cover gives the same complaints. Rule those out before you replace a set. The engine takes six injectors.

Specifications

Fits / Applications

• International MaxxForce 9 & 10, 9.3L, 2007 to 2010
• MaxxForce 9: 300 to 330 hp. MaxxForce 10: 310 to 350 hp.
• Engine serial numbers 3,000,001 through 3,300,000
• Catalogs list International 4400, 4400LP, 7400, 7500 and 8500 TranStar trucks built with these engines. Order by engine, not by truck model.
• Not for the 2010 to 2014 MaxxForce 9 and 10 or the N9 and N10, which take AP66958
• Not for the MaxxForce DT, which takes AP66918 in these years
• Six injectors per engine

The high-pressure oil rail has to come off to change these injectors. The rail’s injector inlet seals must be replaced before it goes back on: use the Alliant Power AP0025 high-pressure oil rail seal kit, which is not in the box. The injectors are fired by engine oil pressure, so change the engine oil and oil filter when you fit them.

Part Numbers & Cross Reference

Alliant Power AP66921  ·  Navistar 1848721C92  ·  Navistar 1848721C93  ·  Navistar 4307212R91  ·  Navistar 5010823R91  ·  PurePower Technologies 6930-PP  ·  Alliant Power (interchange) AP66821

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 AP66921 fit my 2010 MaxxForce 9 or MaxxForce 10?

Only if the engine serial number is between 3,000,001 and 3,300,000. 2010 is a split year, and the later 2010 to 2014 engines take AP66958. Call 530-668-0818 with the engine serial number and we will match it.

Does the AP66921 fit the MaxxForce DT?

No. It is listed for the 9.3L MaxxForce 9 and MaxxForce 10 only. The 2007 to 2010 MaxxForce DT has its own injector, AP66918.

What numbers does the AP66921 replace?

Navistar 1848721C92, 1848721C93, 4307212R91 and 5010823R91, and PurePower 6930-PP.

Is the AP66921 new or remanufactured, and what else do I need?

It is remanufactured by PurePower Technologies for Alliant Power, and a refundable core applies. It comes with the chamber gasket fitted and its seal rings. You also need the Alliant Power AP0025 oil rail seal kit, because the high-pressure oil rail has to come off.

Related Parts

• International MaxxForce DT G2.9 Fuel Injector | Alliant Power AP66918 Remanufactured (2007-2010, 210-300 hp)
• International MaxxForce DT G2.9 Fuel Injector | Alliant Power AP66955 Remanufactured (2010-2014, 215-300 hp)
• International MaxxForce 9 & 10, N9 & N10 G2.9 Fuel Injector | Alliant Power AP66958 Remanufactured (2010-2017)
• 2007-2010 International MaxxForce 9 & 10 16cc High-Pressure Oil Pump | Alliant Power AP63697 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.