This is the Alliant Power AP53801, a common rail fuel injector remanufactured by Alliant Power for the Isuzu 6HK1 7.8L six-cylinder. It is the 2003 model year injector, used in the Isuzu FTR and FVR and in Chevrolet Kodiak and GMC TopKick trucks with the 7.8L Isuzu diesel. It replaces Denso 095000-0452. A refundable core applies.

Hard starting, a rough idle, a miss under load, white or black smoke, fuel in the oil or a rail pressure fault all point at a worn common rail injector. Dirty fuel, water and a weak supply pump cause the same complaints, so check filters, fuel quality and rail pressure before you replace a set. The 6HK1 takes six injectors. The 2004 and later 6HK1 uses different injectors, AP53904, AP53905 and AP53906, and the four-cylinder 4HK1 uses its own numbers.

Specifications

Fits / Applications

• Isuzu FTR and FVR, 2003, 6HK1 7.8L
• Chevrolet Kodiak and GMC TopKick, 2003, with the Isuzu 6HK1 7.8L
• Old injector marked Denso 095000-0452
• Not for 2004 and later 6HK1 engines
• Six injectors per engine

Fit new fuel filters and make sure the tank and lines are clean before the engine runs. Keep every fuel connection capped until it is made up, use new sealing washers and O-rings, and torque the hold-downs and high-pressure lines to the Isuzu service manual figures.

Part Numbers & Cross Reference

Alliant Power AP53801  ·  Denso 095000-0452  ·  Later 6HK1 injector, 2004 to 2007 (different part) AP53904  ·  Later 6HK1 injector, 2004 to 2007 (different part) AP53905  ·  Later 6HK1 injector, 2007 to 2009 (different part) AP53906

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

Which trucks take the AP53801?

The 2003 Isuzu FTR and FVR and the 2003 Chevrolet Kodiak and GMC TopKick with the Isuzu 6HK1 7.8L diesel. Call 530-668-0818 with your VIN and we will confirm it.

What number does the AP53801 replace?

Denso 095000-0452, the injector fitted to the 6HK1. Read the number on your old injector and tell us what it says.

Will it fit a 2004 or newer 6HK1?

No. The 2004 to 2007 engine is listed under AP53904 or AP53905 and the 2007 to 2009 engine under AP53906. They are different injectors and should not be mixed.

Is the AP53801 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.

Related Parts

• 2005-2007 Isuzu NPR-HD, NQR, NRR & GMC W4500 4HK1 5.2L Fuel Injector | Alliant Power AP53903 Remanufactured
• 2008-2010 Isuzu NPR, NPR-HD, NQR & NRR 4HK1 5.2L Fuel Injector | Alliant Power AP53907 Remanufactured
• 2007-2009 Chevy Kodiak C6500, C7500 & T-Series Isuzu 6HK1 7.8L Injector | Alliant Power AP53906 Remanufactured
• Isuzu 4LE2 2.2L Tier 4 RHF3 Turbocharger | IHI F31CAD-S0182B New (Isuzu 8982236170)
• Common Rail Diesel Injector Testing & Rebuild Service

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.