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Fuel Injector WTF...

I'm replacing the #6 fuel injector on my 2006 Dodge Ram 2500 4x4. This post is being edited as I run through the operation. So far this has taken me a few weeks due to the fact that I have a second vehicle, I wanted to take my time and document the process, and I wanted to do it right, which requires me to do some research when I get to a WTF moment. ;)

This is a document of my adventure. Maybe someone else will find this useful; or a source of extreme entertainment.

This has quickly turned into a full injector inspection for the truck. Not a bad thing. The labor is only slightly more for the additional cylinder. As you will see after you take everything off to get to one, the rest aren't that much more.

Truck Details

2006 Dodge Ram 2500 4x4 Laramie Extra Cab w/ 8ft Bed
5.9L I6 Cummins 24v Turbo Diesel (Engine: BT6A)

Miles: 89K

Replaced parts so far:

  • Exhaust Brake Vacuum Pump
  • Coolant hose replacement
  • Front Brake Pads

Yes, seems like low miles for an injector failure. But as of now this looks to be a failure in the Solenoid (electrical) part of the injector.

First Failure

Driving to the airport from Everett WA to Sea Tac, get about to Seattle and check engine light comes on and the truck all of a sudden shudders, has very little power, and starts to run rough.

Power returns sporadically for a min, get to a spot to stop and check it out. Don't see anything obviously wrong, I'm not pissing oil, and I don't see any leaks. No diesel in the engine compartment.

Start the truck back up, idles ok. Go to take off, then it's rough again and gutless. All this time it's not really kicking out any smoke other than when I put my foot in it trying to figure out what the problem is.

Park the truck overnight at the airport (was able to limp it along) come back the next day after doing a little research on my problem.
The main consensus is the injector is stuck open leading to the rough idle, lack of power etc...

So one of the things that can happen apparently is the wiring harness that is used in this model year has a tendency to go bad. The wires run through the valve cover using this gasket/harness and sometimes the wire harness on the outside can get loose or dirty.

Also I found a way to read the check engine code on the truck without needing an ODBII reader (they are cheap, but I didn't have one ATM)

Turns out to be injector #6

So I unplugged the two and rehooked them up. Started the truck and no problem. Don't even have any stuttering or anything for the next couple of months.

Last Failure

Well a few months later, I'm driving the kid to a School Band function. Check engine light comes on again and same exact rough idle. Fortunately this time I'm fairly close to the house, so gimp it home again.

Again it's injector #6.

Diagnosing the issue beyond the computer

Tools Needed

  • 19MM OR 3/4" Wrench: Fuel Line Nuts
  • 24MM OR 15/16" Wrench / Adjustable Wrench: For holding onto and removing the Injector Tube Nuts.
  • 24MM or 15/16" socket for tightening the tube nuts via Torque Wrench
  • 8mm Socket - Fuel Injector retaining nuts, Injector Solenoid nuts
  • 10mm Socket - Rocker arm nuts
  • Set of crows foot wrenches in the sizes above to make some of the tighter spots a lot easier to access
    Auto Zone 8pcs Set
  • Volt Meter to check the impedance on the injectors
  • Sharpie
  • Lots of zip lock bags (sandwich size mainly)
  • Custom Injector Pulling Tool

Here are the specific custom tools listed by Dodge for working on the engine as a whole

Custom Tool Notes

NOTE : When working on the fuel lines use the two wrench method. This will keep you from breaking a fuel line if the fuel line nut is tight and the injector tube nut starts to give away first. This will result in your twisting the fuel line tube and either breaking or weakening it. Be careful these lines are $$. Also take is slow, if you get frustrated and try to force things you could end up creating a problem that only happens when the fuel lines come under full pressure, and at 25K - 30K psi, this is not the time to find out.

BEFORE YOU START

Be prepared to bag and tag EVERYTHING, you don't want to put the engine back together using whatever parts "fit". Everything that comes off for Cylinder 1 goes back to Cylinder 1. It's always best to put everything back where it came off at. This makes additional troubleshooting more clear.

For Reassembly
Pulling it all apart to diagnose
  1. Remove Valve Cover
Checking Injector Impedance

0.5 - 0.6 = GOOD
anything above this value means it's bad, time for replacement

Replace the Solenoid or whole Injector?

Fuel Injectors are actually composed of several parts. Effectively allowing for them to be remanufactured by replacing seals, the solenoid and various other little bits. Since this is my first time messing with this, I'm just replacing the injector outright. I could buy a new solenoid and replace that on the injector itself, but that's considerably less clear if that will be a success here. Either way if you wanted to repair the Injector yourself this is possible. You have to remove it anyway so same steps below.

Pulling the Injector
  1. Remove Boost Input
  2. Remove Heater Block
  3. Remove Fuel Lines
  4. Remove ExhausT Rocker
  5. Remove injector retaining bolts (8mm)
Inspecting everything
What to look for
Cleaning everything up
  • Clean diesel fuel
  • Wire bore brush
PHOTOS

Courtesy of Diesel Logic [1]

Stephen posing, little does he know he's about to learn why we cuss when working on vehicles. We still have the gasket and air intake on

Here is a view of the Valve Cover and Gasket Removed.
Exhaust Rockers are the bigger ones, intake rockers are the smaller ones. Here the fuel lines are still running into the injector tubes.

In the process of removing the High Pressure fuel lines

The #6 injector is all the way in the back. Sweet....

OMFG they clearly put this thing together outside of the engine compartment. This plate which was probably used to lift the engine into the the truck sits infront of the the #6 injectors fuel line and access to the injector tube

Here you see the #6 fuel line now that the plate has been removed

Here is the photo of the hole the injector came out of, this is #1, pulled for reference. The black stuff is diesel/oil buildup that was on the injector. Based on this I decided to pull all the injectors and clean up everything. I've got it apart at this point.

Putting it back together

Here is where we will use our Torque wrenches. Either rent of buy, but doing things hand tight is not what you want to do here.

Fuel Injector install steps [^3]
  • Step 1—Install injector hold-down capscrews and torque to 5 N·m (44 in. lbs.) torque.
  • Step 2—Loosen injector hold-down capscrews.
  • Step 3—Install HPC connector tube and nut. Torque nut to 15 N·m (11 ft. lbs.) torque.
  • Step 4—Torque injector hold-down capscrews to 10 N·m (89 in. lbs.) torque.
  • Step 5—Torque HPC connector tube nut to 50 N·m (37 ft. lbs.) torque.

References Used


  1. Diesel Logic http://diesellogic.com ↩︎

Fuel Injector WTF...
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