'04 LB7 Group 1 injectors quit pumping

[TMAUG]

Hello, I have an '04 LB7 with Codes P2146, and the 4 injectors fail codes (#1,4,6,7). We have done electrical tests to insure power through the FICM to the injectors. We have gotten feedback from other forums on some of the wiring issues, some of those ideas were for the LLY. Wiggling the wires did not cause a difference in the running. We are in the process of testing the 4 injectors on the drivers side today. I read this morning that if 1 injector fails, it will cause all the injectors in that group to shut down until it is replaced. Any thoughts? Thanks!

[Willcoc]

After changing injectors, we has the same issue. We checked everything everyway except for looking for something going to ground. Turns out #6 was grounded out. That was after I got a FICM module and nothing changed. At least where not to hard to undo but still a major time. Took things apart and the ground disappeared so not sure what was not correct but no return of issue.

[More Power]

Hello, I have an '04 LB7 with Codes P2146, and the 4 injectors fail codes (#1,4,6,7). We have done electrical tests to insure power through the FICM to the injectors. We have gotten feedback from other forums on some of the wiring issues, some of those ideas were for the LLY. Wiggling the wires did not cause a difference in the running. We are in the process of testing the 4 injectors on the drivers side today. I read this morning that if 1 injector fails, it will cause all the injectors in that group to shut down until it is replaced. Any thoughts? Thanks!

I wrote a tech article on this very problem back in 2003. Here is an excerpt from that piece.

The eight fuel injectors are broken down into two groups - Group 1 (cyls 1-4-6-7). An open or grounded injector driver circuit in Group 1 will set a related DTC. In your case, the DTC set when the HSD (High Side Driver) or LSD (Low Side Driver) circuit for Group 1 was open for approximately 32 milliseconds (.032 seconds) as detected by the FICM. copyright The Diesel Page
This DTC usually accompanies a combination of codes P0201 through P0208 (individual injector driver problem - electrical). When a problem like this occurs and the engine RPM does not stabilize, the ECM will command the FICM to shut down the affected injector group (depending on which group the bad injector resides).

Suggested troubleshooting sequence:


Verify customer concern.
Check for and record all stored diagnostic trouble codes.
Inspect FICM electrical connectors and FICM wiring.
If all related wiring and electrical connectors appear normal, remove valve cover (or covers) as indicated by which DTC codes (P0201 through P0208) were set, and check for loose electrical connections at each injector. Tighten any loose connections.
If injector electrical connections were not loose, R&R affected injectors. Note: If this is a non-warranty repair, you can swap one or more injectors from one cylinder group to the other, to help you determine which individual injector is at fault.
If the above didn't solve the problem, R&R the FICM.
If the above didn't solve the problem, R&R the ECM.