Buy 5364204 - Genuine Cummins Fuel Injector 2019-2021 ISB 6.7L - wisentpartscenter.com

Description

Cummins R8444790AA Fuel Injector - Genuine Bosch Common Rail Injector for 2019-2021 ISB 6.7L High Output

The Cummins R8444790AA is a genuine Bosch common rail injector for the high output 6.7L ISB, 2019 to 2021. It holds rail pressure until the ECM commands it open, then atomizes fuel straight into the cylinder through the nozzle. R8444790AA fires several times per combustion event, which is how the ECM controls timing, quantity and combustion noise. Bosch number 0445124039. Also listed under 5364204, 5364204NX, and Mopar 68444790AA, R8444790AA and R8504671AA.

Key Functions:

- Injects fuel directly into the cylinder at common rail pressure
- Fires pilot, main and post injection events per cycle off ECM command
- Solenoid operated with an individual flow calibration code

Fitment & Specifications:

- Cummins ISB 6.7L, high output
- Ram 2500 and 3500, 2019 to 2021
- Bosch 0445124039
- High output

R8444790AA is the high output injector. The standard output engine uses 5364205 and the two do not interchange. Verify by engine serial number or VIN before ordering.

Purpose of the Part

R8444790AA is the piece that actually meters fuel into the cylinder. The high pressure pump keeps the rail charged and R8444790AA sits closed against that pressure until the solenoid is energized and the needle lifts. How long it stays open is the only thing controlling how much fuel goes in, so nozzle condition and internal leak by change the fueling on that cylinder directly. On the high output engine the injector is spraying a different quantity than the standard output unit, which is why the two part numbers are not swappable even though they physically fit the same head.

Issue Symptoms / When to Replace

Typical signs are a rattle or knock from one cylinder, rough idle, misfire, hard starting, white smoke on a cold start, low power, poor mileage and cylinder balance codes calling out one hole.

Fuel contamination and water are what kill these. Debris scores the nozzle and internals, the injector starts dribbling instead of spraying, and you end up with washed cylinder walls and fuel getting past the rings into the oil. A rising oil level with a fuel smell is worth checking any time you suspect an injector.

Run a return flow test to find the bad injector before pulling anything, and check rail pressure, the high pressure pump and the filters first, since a supply side problem hits every cylinder and looks similar. If the pump has failed and put metal through the system, do not reuse injectors.

Brand Information

Bosch flow tests every injector and marks it with a calibration code the ECM uses to trim that specific hole. Cummins specifies a different flow for the high output engine, which is the whole reason R8444790AA exists as its own part number. Running standard output injectors or uncoded copies in a high output engine leaves the ECM correcting against numbers that do not match the hardware, so the truck idles rough and sets balance faults even with new parts in it.

Installation Notes

1. Figure out what took the old injector out, dirty fuel or a failing pump will do the same to R8444790AA.
2. Replace the filters and check the water separator before anything goes in.
3. Cap every line and fitting and keep the work area clean, debris is the main reason injectors fail twice.
4. Fit new connector tubes, do not reuse the old ones.
5. New copper washer and new O-rings on R8444790AA every time.
6. Torque the hold down and high pressure line to spec, uneven torque leads to leaks and cracked tubes.
7. Write the calibration code from the body of R8444790AA into the ECM with a scan tool, without it the engine idles rough and sets balance faults on brand new injectors.
8. New valve cover gasket on reassembly.
9. Prime the system and check for leaks at idle before putting a load on the engine.

How to Identify an OEM Part

A genuine unit has the Bosch name and logo with the Bosch part number laser etched into the body, along with the individual calibration code. Check the numbers on the body against what you ordered, and confirm it reads 0445124039 rather than the standard output number. Copies usually have uneven or printed markings, no calibration code, and a nozzle nut or body finish that does not match.

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Warranty & Return Information

Warranty Information

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