My Monaco DP has 255 counts of a 2388 code. This appears to mean that the turbo (wastegate?) actuator isn't rotating enough. They suggest I replace the turbo ($4,600 + 16 hours labor = ~$7,000). I believe this is the ISB engine in either a 275 or 300 HP configuration.
So, questions:
1) Is there a way to loosen up the actuator rather than replacing the whole thing? Could it be stuck after sitting for two years and might actually fix itself after running it normally for a while?
2) What are the likely consequences of not replacing it?
The boost gauge is going from zero to over 30 PSI of boost pretty smoothly, so it's getting enough boost. From tuning VW's, though, I know too much pressure can be a bad thing. What's the limit on these turbos?
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I can't be sure if this thread has any info that could be of use , being a newer version of the ISB. But it might be worth a read .
JMHO: For $7,000 I'd be tempted to drive the coach , over boost should set codes and cause the engine to de-rate before there is any damage.
EDIT: A second JMHO 16 hour quote for a turbo replacement is their ," we'll work on your coach for a price quote " if you do decide on replacement , shop around for price on the turbo and labor charges , 16 hrs. would strike me as being double the time involved . I know every engine and coach will have different access issues , but I had my turbo off in well under 3 hrs. to remove a broken fitting for my waste gate actuation pressure hose . The fitting had been damaged when the engine was lowered into the chassis and the motor survived 11 years and 62,000 miles with the waste gate not operating , I'd driven the coach 7,000 miles myself , and didn't notice any problems , spotted the damage while changing the oil filter.
You probably have the same Cummins 5.9 ISB common rail engine that I have. I would be tempted to check the waste gate movement, replace the actuator, and if that didn't work. Pull the turbo for rebuild. This is easier or harder based on access to your engine. Good Luck.
as to boosting a cummings, they can be modified to the point of insanity..and you always have your foot on the pedal and your gauge to read the pressure... keep in mind they are extremely costly to fix once broken.
Update: On picking up the MH I talked with the service department a little more. They reset the codes before taking it for a drive checking the alignment. The check engine light didn't come on while they were driving it, nor have I seen it in my limited driving of it since I got it back.
IWander: Did you get a new turbo? Do you have a Holset-40W or a newer style turbo?
This subject has been talked about a lot in this thread about ISC-350 boost in 2004 and earlier coaches, where we are trying to disable the turbo actuator to increase our boost to 30PSI.
So if you are getting 30PSI you probably are enjoying better performance and maybe lower EGT numbers.
...And the only thing you have to live with is knowing you ECM is flashing high counts of over boost. So can you turn that option off using the Cummins Insite Programmer? ...Ask your mechanic and let us know what you end up doing?
Alternatively, maybe your engine has a speed sensor that is picking up these faults? If so, maybe you can fool it somehow?
IWander: Did you get a new turbo? Do you have a Holset-40W or a newer style turbo?
I don't know what kind of turbo I have. At six or seven grand to replace it I'm going to need to see a problem beyond a check engine light before I tackle it. Also I'm heading to San Diego in a few days and don't have the time to do anything with it now.
I'm pretty sure it's a matter of carbon buildup, and am hoping active use of the exhaust brake and running it hard on some hills will clean it out.
I don't know what kind of turbo I have. At six or seven grand to replace it I'm going to need to see a problem beyond a check engine light before I tackle it. Also I'm heading to San Diego in a few days and don't have the time to do anything with it now.
I'm pretty sure it's a matter of carbon buildup, and am hoping active use of the exhaust brake and running it hard on some hills will clean it out.
Thanks for all the pointers,
David
Had similar issue with my 6.7 Cummins. It appeared carbon buildup caused actuator and turbo problem. Original owner noted the issue but did nothing, noting only check engine light when under load. I chose to replace actuator and turbo for $6000 and no more problems. Prior to changing, I did try having actuator changed and turbo cleaned. For me this didn’t fix problem.