Turbo not kicking in???

[Alton]

I tow a 30' fifth wheel, just under 11,000 pounds, wet. Now towing with my 3rd Cummins('07. 5 Laramie, 6. 7L, 2500, 4x4, 6 speed manual, all stock). It seems to me that the power boost from the turbo isn't kicking in and the hills are slowing me down more than ever before. Truck has 8900 miles on it and has had all 3 flashes. Went in to a dealer in Bangor, Maine today. They tell me they can't find anything wrong, even after talking to "factory techs" and running the suggested tests. The dealer tech suggested I change the fuel filter, that I may have gotten some dirty fuel, which I haven't done yet. Has anyone out there experienced a power loss such as I have described?? It is much more obvious when pulling up hill and not so much while solo.

Any suggestions will be appreciated.

 

[DCreed]

how are the EGTs? perhaps the trap is full or the E-brake isnt fully opening?

 

[Sky]

I have been noticing last week that a few times I can hear my turbo kinda stumble mostly when the EB is on and I could feel it stumble so not sure what that is about but so far it has not gave me the CEL. 7500 miles so far.

 

[Alton]

EGT hasn't ever gone over 1200*. (Pyrometer is post-turbo)The dealer here in Maine(We're from Washington state) tells me the tests indicate the trap is good. Also, said there have been 12 regens in the 8800+miles which is "normal".

Can you tell me how to determine if the EB is not opening fully? It sure seems to kick in when the switch is on and I want to slow down. No problem in hearing the effects of the brake.

I plan to change the fuel filter but my hopes aren't high to find that to be the solution. If the filter was even partially clogged wouldn't the fuel pressure psi be reduced thereby causing code faults??

Thanks again.

 

[Alton]

The only thing I've heard that was strange is the EB occasionally cycles on/off at idle. Again, I'm told that is normal and part of the exhaust gas clean up process.

Who knows---I'm not much of a mechanic but after owning two other Cummins I know how these things should perform. Mine is not up to par.

Thanks!

 

[Sky]

Only 12 regens in in 8800 miles? Thought it was A LOT more then that. .

 

[Alton]

My understaning is that "normal" as it pertains to the number of times regens occur is determined by the way the truck is being used. Almost all of the 8800+ miles on mine were put on while, under load, that is towing. The EGTs are hotter than if one is running solo, thereby avoiding some of the particulate accumulation. That being said, I don't know how confident we should be with the information we are getting at this point. It seems there is a difference of opinion with every Dodge "diesel tech" I talk to. Normally I would take my truck to Cummins Northwest in Yakima, WA, tell them what is going on and they would give me an accurate diagnosis , then fix the problem.

 

[DCreed]

I would drop a dime to Yakima and ask their opinion, its free. Also 1200 POST turbo is HOT, so I would then suspect a blockage/restriction of some type. perhaps the trap is not fully cleaning or waiting too long (between cycles) to clean. E brake inspection SHOULD be able to be done visually but I'm not familiar enough with the 6. 7 to say. This truck/motor is new to all of us so please spare no details of its operation or hiccups!

 

[DCreed]

A second thought, that is a variable turbo right? is it functioning correctly? there have been problems with some of the designs clogging the vanes with soot, I wonder if Cummins solved that issue?

 

[MCummings]

how are the EGTs? perhaps the trap is full or the E-brake isnt fully opening?

This may be possible, but the e-brake is a part of the exhaust housing. If the e-brake were not "fully opening" the there would also be overboost codes.



Merrick

 

[Dishman Dodge]

Alton,

I know for certain of 2 6. 7 trucks we have had here (one was a buddy of mine) where we had to replace the turbo. the truck my friend owns is a daily driver, but also does heavy equipment towing with it. It would run great, but many times, he would go to get on the throttle, and the truck would act like it had no boost, same scenario as teh other truck. both trucks had a cel (not exactly sure at this point which one). on the first truck, chrysler told us to start tearing apart the turbo, and then half an hour later, called us back and said to just ship it back, so on my buddy's truck, they just said they've seen the problem, and they would ship us an entire new turbo, not telling us what the issue is. The best the tech and me can figure is that the electronics are faulting, not telling the vanes to close at low speed/rpm, and they are staying open, acting like a large turbo. since my buddy had his replaced, no more cel and no more turbo lag.



-Josh

 

[Alton]

Josh,

I will be going to see a dealer at the earliest time possible. I'll post an update as soon as the results are available.



Ypur help is appreciated and thanks also to those of you that took the tme to respond.



Alton

 

[Dishman Dodge]

Alton,

Good luck, and as i said in my pm, reference me if you wish, and they are welcome to call me and i will get them as much info as i can on the trucks we have had the same repairs on.

-Josh

 

[MisterScott]

I would be very interested to see if this develops into a recall issue.

 

[Dishman Dodge]

GUESS WHAT!!!

I was just down with the tech. and he had ANOTHER turbo he is replacing!!!

 

[DavidBentley]

I was getting P2262 codes before they replaced the turbo on my 6. 7L. Mine would get the code immediately on startup. The tech believed the problem was the turbo checks itself at startup by sliding on it's shaft all the way to the stop and back. Due to corrosion or carbonization it was not sliding correctly and throws the code. I did not ask if the replacement turbo charger is the exact same unit or if it has been updated to not have this problem in the future.

 

[Alton]

Here is the latest, not the greatest. Stopped at a dealer in New Hampshire. They ran various tests and then the tech talked to Chrysler, which told him the Particulate Filter was fullly plugged. A new one was ordered in and installed. It made no difference at all.



The biggest obstacle to a correct diagnosis is the technician's lack of experience in working with the 6. 7L engine. Most all of the them admit, up front that the engine is so new that they haven't seen enough of them to have any reference to look back on.



The only thing new is that yesterday while pulling a minor grade in 4th gear if that the engine sounded like it "coughed". My wife described it as,"sounding like a backfire".



I'm having to down-shift like never before, even with my old '96, 12 valve and getting to lower speeds than ever just to move on up the hills.

 

[TAbbott]

If the DPF was plugged, maybe the catalytic converter (I think it still has one of those) was plugged as well. The tests they ran must have indicated excess exhaust restriction or they'd never have replaced the DPF (spendy). I think that'd be the next place I looked... Also, the symptoms you cited indicate a gradual degradation of performance over time, which would fit the condition of the convertor or trap gradually becoming plugged. It could also have to do with the egr system not functioning properly and giving it too much recycled exhaust relative to the amount of fresh air it's getting. That could cause the over rich condition that leads to the plugged aftertreatment devices. When one part of the emissions system isn't funtioning properly it's like a death spiral where the performance just keeps going down and down. It's the same way with the big trucks, even those with the '02 systems. I'm sure the '07 stuff is even worse... Works great when it works. Pain in the *** when it doesn't.

 

[Alton]

Your points are well taken. In fact, I've sent out an inquiry about the EGR sensor probe. Ive been told that the capillary tube(sensor) should be bright, shiney. Yesterday, at my request, the tech removed it and found it coated with soot. He cleaned it and we went out on a quick test drive, a half mile or so,returned and removed it again. It was already coated with soot in that short drive. Having no experience with these engines, he had no idea if it should be sooty or not, nor was he certain what the function of the EGR sensor is all about.

Thanks for your thoughts.

 

[sag2]

Your tech seems like he is trying. Can you ask them to drive it with the trailer and with the StarScan hooked up. Then they can see the actual boost under load. Low boost can be incorrect turbo operation or plugged exhaust. Did you ever change the fuel filter? You need to start with the easy stuff.

As for the turbos being replaced as referenced above, most of the time they are carboned up and the actuator can not slide the nozzle so it throws a code. The latest flash is supposed to actuate the brake every so often when you are in decel to wipe the carbon off the actuator shaft. It also parks the turbo in a random spot on shut down, and cycles it on key on to help keep it free.