Looking for part number for the injector/valve cover flex harness

[Crunch]

I have an '03, so I don't have the integrated valve cover gasket. I've been trying to track down the cause of an intermittent but persistent P2146 code. I think I've pretty much eliminated the ECM and injector solenoids as culprits, which leaves either the main wire harness or the little flex harnesses that pass under the valve cover and to the injectors. I'm taking my truck to a dealership next week for a second opinion on the injector solenoid resistance, but he told me that in his experience the flex harness is a common culprit though he didn't know the part number or price. I want to find out as much about it as possible, specifically price and availability but couldn't pick it out of the drawings in either the Dodge parts manual or Dodge repair manual PDF's. Does anyone know the part number for these flex harnesses, or the proper name that will help me track down more information on them? Thanks.

 

[BigPapa]

Give me your ESN and I’ll get you a Cummins part number.

 

[Crunch]

Give me your ESN and I’ll get you a Cummins part number.

Engine Serial Number: 57038705

Thanks.

 

[cerberusiam]

Have you ohmed the harness to make sure it is good? The harness is wires and connectors, if those are good and you cannot find an open when you flex them they are likely good. The random codes are more likely injector solenoids than anything else. The harnesses under the VC are available in multiple places, we just bought to update the harness for the 6.7 project. I will see where my son found them for alternate choice.

 

[BigPapa]

I'm guessing this is them since they're not shown in the illustration. It shows there three of them with the Engine Control Wiring Harness. Looks like they're $65-$70 online from multiple sources.

Cummins #3966805

 

[Crunch]

Have you ohmed the harness to make sure it is good? The harness is wires and connectors, if those are good and you cannot find an open when you flex them they are likely good. The random codes are more likely injector solenoids than anything else. The harnesses under the VC are available in multiple places, we just bought to update the harness for the 6.7 project. I will see where my son found them for alternate choice.

Haven't ohmed the harness, but I have flexed it to see if I could duplicate the problem, or fix it if it was occurring. Injector solenoids were my first inclination, based on the new/reman discussions here. Since the injectors were replaced by the local Cummins Southern Plains shop I took it to them because the injectors were, and still are under warranty. They checked them twice, and found no problem with impedance on the solenoids. The ECM has also been evaluated/repaired twice, once under its lifetime warranty. So unless either shop made a mistake it pretty much has to be one or two of the injector harnesses or the main wire harness. I talked to the diesel mechanic at a local Dodge dealer and for 1.5 hours of labor they will run through their process for diagnosing the P2146 code, and that included checking impedance on the injector solenoids. I figure for that price it's a good second opinion, and I really hate tracking down electrical problems in vehicles, especially vehicles with computers. Based on my explaining the situation to him, he suggested looking at the injector flex harnesses first if the injectors check out. And since the valve covers will be off for that I would probably let them replace the harnesses for Group 1.

I'm guessing this is them since they're not shown in the illustration. It shows there three of them with the Engine Control Wiring Harness. Looks like they're $65-$70 online from multiple sources.

Cummins #3966805

Bingo! I think that's them, based on the Google image search I did. Thanks for the part number!

 

[cerberusiam]

The problem with the solenoids is unless they go completely bad they will intermittently show a problem when warm and shop will never find the issues. Try the harness and if that doesn't fix it then it is a solenoid and until it gets bad enough to identify cylinder you will have to guess.

 

[Crunch]

The problem with the solenoids is unless they go completely bad they will intermittently show a problem when warm and shop will never find the issues. Try the harness and if that doesn't fix it then it is a solenoid and until it gets bad enough to identify cylinder you will have to guess.

The Cummins place put the truck on the dyno and got it up to operating temperature when they tested it. Since the injectors only have about 10K miles on them I would be tempted to have the dealer switch out the solenoids on all the Group 1 injectors if they can't find anything else. It would definitely save a lot of aggravation, and I could eat the cost for the peace of mind I would get. While I could probably do the testing myself, it would be near the limit of my skill set and far beyond my existing experience. I've never had a vehicle with fuel injectors before this, or a vehicle with this kind of electronics.

 

[cerberusiam]

Dealer won't switch solenoids on injectors and you don't even want them to try, they really will be junk then. Dealer would only replace with some of the worst remans available.

Remans are a crap shoot no matter what anyone says. New injectors cost about about $40 more per unit unless the seller is greedy, little reason to even consider remans anymore.

Even if they tested at operating temp the intermittent faults you are seeing are hard to recreate. As I said before, unless it fails hard and stays failed very tough to isolate which one it is.

 

[BigPapa]

Just relaying my experience here.

We use quite a few Cummins remans in our 650+ buses with good success. Out of 120 Cummins reman injectors we've installed, we've only had two replaced under warranty.

Now, CAT is a different story. Out of the 85 we've installed, we've had eight replaced under warranty.