Last week, I asked about issues with my Ram. It was throwing a code (P2146). Shortly after that happened, the ram started idling VERY roughly and lost a considerable amount of power. I had it towed to the dealership where the harness for the 1,2,and 3 injectors was replaced. After I picked it up and drove it for about 20 minutes, the exact problem started again.

It appears that this is a problem that only occurs after the truck is warmed up. it has a new harness on it, so what could it be? Could it be an injector issue? Lift pump? The truck is a 2005 Ram 3500 auto. The tech seems to believe an injector is failing once the truck gets warm, but he will have to drive the truck for a while to replicate the issue so he can then test for the problem. What do you guys think?

What does code P2146 translate to?

what year ??????

03 and up had a solenoid issue on the back of the injection pump is it stalling wont start more details.

with the scan tool are you seeing a fuel pressure change between key on and cranking ???????

2005.

Its not stalling, just suddenly idling very rough and losing power. when the truck cools down, everything works fine until its warm again.

I don't have a scan tool to monitor fuel pressure so I can't tell you.

The OBD scanner threw P2146 which is: Bank one-cylinders 123 short circuit high or low.

The harness was replaced as it is a fairly common problem, but issue persists.

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The OBD scanner threw P2146 which is: Bank one-cylinders 123 short circuit high or low.

The harness was replaced as it is a fairly common problem, but issue persists.

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That indicates the problem is further back from the new harness or there is an injector problem.

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It appears that this is a problem that only occurs after the truck is warmed up. it has a new harness on it, so what could it be? Could it be an injector issue? Lift pump?

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The 1st thing that should have been checked is the lift pump pressure when the truck starts running rough.

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The tech seems to believe an injector is failing once the truck gets warm, but he will have to drive the truck for a while to replicate the issue so he can then test for the problem. What do you guys think?

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I would not trust the tech who threw a harness at the problem without any testing and did not drive the truck to make sure he had fixed the problem correctly. I certainly would not pay for the harness or labor.

They/you need to look at the signals to the injectors when the problem is occurring. If the signals look like the cylinders 4,5,6 signals, the problem is most likely an injector.

A heat gun is a valuable tool for finding heat related problems. Preheat the lift pump when the truck is cold and keep heating for a few minutes while running. You can do the same for components previous to the new harness.

You can swap injectors one at a time from 4,5 or 6 to see if the problem moves or buy/borrow one good injector and move it from 1 to 2 to 3 and see if the problem goes away.

Wow...wasnt expecting THAT much info

Fortunately, the engine is still under the cummins warranty (5 years 100,000 miles) so this was a good time for this to happen if it was going to.


Unfortuantely, I am kinda suspicious of the guy who throws the harness at it too. Especially when he told me that is what he did (his words "The harness is a faily common problem so I replaced yours."). Unfortuantely, Cummins Atlantic won't work on post-2003 Dodge trucks so I am left with the Dodge dealerships around here, neither of which have a very good reputation. I mean, the tech seemed pretty knowledgeable, but it bothers me that he didnt go more in-depth about it.

I have ran into this problem before and it turned out to be an injector. Unfortunately as you have stated it happens when its hot and the ecm doesn't specify which injector, just which bank. If it's still under warranty and they cant determine which one of the 3 injectors is faulty, I would be looking for 3 new injectors!!

The valve cover gasket has the harness made in to it. Often times the harness is nearly impossible to diagnose due to failure only when hot and under pressure from the valve cover screws. It is a common issue. Your issue is most likely an injector shorted which will cause the loss of that entire bank. The tech spoke correctly, he will need to ge tthe truck hot and then either perform an injector kill test or OHM out each injector looking for the one with the short.

Don't be too quick to assume everything is warranty. If the injector is found to be fouled due to trash or fuel contamination Chrysler will not warranty it as that is not considered a defect in factory craftmanship.

I agree that the tech should have done a validation of the repair, but he was right in replacing a known, common problem. Less time spent and a weak part replaced means less billed and a customer with a (hopefully) better harness even if it didn't fix the issue.
Give him another shot, but make sure you inform the service writer that this is a comeback for the initial problem. Hopefully you will not be billed for any additional diagnostic labor, even if it's not a warranty issue.

Craig, I had an injector go wide open, pour raw fuel in a cylinder, and hydrauliced the motor causing it to throw a rod! Injector problems are nothing to be casual about...