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No Power on Diesel Engine

I have a Cummins ISB 350 with CM2150 in my 2008 Discovery 40X motorhome. Right now the engine does not seem to have any power. It will get up to speed, but VERY slowly. Both fuel filters have been changed. IF you step on the throttle, there is NO thrust; NO surge, just a gradual and slow increase in speed.

Does the turbo sound OK? No check engine light?

Everything sounds normal. There are no visible or audiable clues - no lights - no smoke - no noises

Is there a mechanical linkage from throttle to fuel pump/distributor, or is it electronic?

Is there an OBD-II (or equiv) port to monitor the engine with a scanner?

Filters were changed but did you add any fuel treatment to the tank ? In cold weather the fuel gets waxy .

I do not know the answer to either of your questions. However I do know that the engine was hooked up to a dyno machine and there were no error codes

No additive was added. However, I am in Florida and the lowest the temps were lately were in the upper 40’s to low 50’s.

No additive. We live in central Florida and the lowest temps lately were in the upper 40’s

Hi Gettinthere,

Check the lift pump. It provides fuel to the injector pump. If the lift pump is low pressure, then the injector pump has limited access to fuel. In a diesel: FUEL = POWER. There is no throttle, and no air metering system.

Also, make sure that when you changed the filters you removed any entrained air-- sometimes entrained air in the filter housing or lift pump chamber can cause the same symptoms.

Good luck,


Hi Matt,

Thanks. Your suggestion is well said and I will pursue it. The motor coach is at my mechanics and I have been trying to help him troubleshoot the problem. After I pass on your suggestion and get his response, I will forward it on.

This is a long-shot, does not happen very often, but sometimes a restriction can develop in an exhaust system which will reduce power in any engine…A fairly simple matter to check, even if they must drill a hole in the exhaust pipe to measure back-pressure.

Is your mechanic familar with the injection pump timing procedure for this engine? I admit I am not but on the passenger car diesels I used to work on in the 80’s pump timing was something that could be adjusted and would cause a significant reduction in power when incorrectly set.

I hope the mechanic is but I would like to think incorrect timeing would be evident with excessive smoke, of which there is none. I will mention this to him. Thanks.

I will mention this to my mechanic. Thank you.

It may be that with this more modern configuration pump timing is non adjustable (by the mechanic). With the old diesels used in the 70’s and 80’s era Rabbits you were supposed to set pump timing with #1 piston at TDC at the end of the compression stroke. If you set the timing off any other piston at the end of its compresion stroke the car would run, but it would run very poorly(no smoke though). I never quite figured out why it was important to set timing in reference to #1 piston (this note is in the manual) but I bet you can figure out how I discovered the car would run poorly with the pump timing set off any piston other than #1.

I know about the timing and what’ll happen if it is out. This unfortunate experience occurred to me in my boat when one of my diesels had to have to Injection Pump removed and my mechanic had great difficulty getting it back to the correct timing - resulting in rough idling, smoking, both.
However, non of these symptoms are with this current problem - only lack of power.

I have great hopes for the lift pump idea.

Sorry for the delay, but the problem was finally identified and remedied bu Cummins. It needed a new ECM. I cannot say what exactly led Cummins to that answer except to say it required an engineer who seemed to recall another engine with an unexplained loss of power that was caused by a faulty ECM. Once the ECM was changed, the problem disappeared.
My only concern is now, why did this happen? I am not sure I will ever get that answer. Thank you to everyone who responded with suggestions. Maybe I will be able to help in the future.

I always like to know about ECM replacements so I ask, who paid?

It was under warranty so Cummins paid. are you aware of problems with who has paid in the past? It was a pricey item, I think about $3500?? Are you aware of any follow up problems that I might want to keep a lookout for? Thanks.

When you changed the filters…did you BLEED the fuel line/system afterwards…Do you have a book on your engine? It may beed to be bled now…but if bleeding is an issue you usually will have a no run condition.

I dont know what type of fuel delivery system you have but if it is like my 00’ VW TDi…In that vehicle there was a fly by wire system…in fact the accelerator pedal had no connection to any type of common butterfly valve i.e. in your throttle body…this “throttle body” was WIDE open…the vehicle would fuel itself directly from the accelerator to ECU…then the ECu would tell the pump assy how much fuel to flow and thus how fast to rev the engine… I am fearing that you may have an issue with your fuel distribution pump…OR your injection TIMING…VERY IMPORTANT TO CHECK THIS…

I will have to look up the specifics on your vehicle to see what type of system you have. Sounds like a fueling issue to me…but I will need to see what system is in there…

Your Turbo could be seized…you can check it by removing the charge tube and using your finger to rotate the compressor wheel…that would make an obstructed exhaust…and if she cant breath properly…you will get this condition…Do you hear your turbo spooling?