hi yall. my truck usually works fine. starts great,idles good,good on fuel,etc. on occasion,she loses power,i can tell she is just not working the same. when its working good,it has that nice cummins rattle at idle,cruise,etc. when she misbehaves,i notice a different sound from the engine.it sounds quieter,and just does not have the power. fuel consumption goes way,and she billows some pretty good smoke from the exhaust.i changed the fuel and air filter. yesterday she worked fine at first for about 10 minutes on the highway,then i could tell she started to get sluggish. i did get a p-0251 code and cel about 2 weeks ago.i came to a stop and she just shut off.i started up again and she was fine.the cel went out after a few starts. anybody have a solution? im all ears. thanks.

 

P 0251 is Injection pump fuel valve feedback.Sounds like you are haveing a problem with the cp-3.Were there any other codes?

 

no their wasnt. the same thing happened just awhile ago. it starts out fine then slowly starts to lose power and smoke. wait a little while,then it is fine again. might i ask what a cp-3 is?

 

ok,i take it the cp-3 is the injection pump.i read on another post it could be the fuel return valve,or the rail pressure pop off valve. make any sense?

 

i just got back from work. same thing happened. starts out great,when engine temp. gets to normal ops. temp,i look in my mirror,black smoke,power goes down,fuel consumption goes up. seems like a definite trend. if i drive for any longer than a half hour,she goes back to normal. rreeaal aggravating !!! another post suggested it could be the fuel control actuator on the cp-3. any opinions out there ??????

 

I would tend to agree.It may be the control actuater,but the engine would sound more like an older 2nd gen if the rail pressure was spikeing.Does it rattle when it's smokeing?If it's not,then you may have a hung injecter.When an injecter hangs open for any reason,it will be shooting fuel into the cyl AT ALL TIMES when the condition persists.This will do several things.It will smoke bad,It will lower rail pressure,sometimes to the point that it will die.Thoe it takes more than 1 to stall the engine.You will also get a fuel control code as the computer tryes to keep the pressure up,& overworks the actuater.This sounds to me like the problem you are haveing.1 or more injecters are hanging open when warming up.Either because of scoreing,or soloiniod failure.Either case,you will need to isolate the faulty injecters,& replace them.I know..Easier said than done,since it only occurs @ sertain temps.If you don't have the equipment to proprely troubleshoot the problem,you will have to take it to someone that does.Good Luck.

 

if i drive for any longer than a half hour or so on the highway,everything returns to normal. lotsa power etc.i can definitely tell a differance in the sound of the engine,especially at low power and idle.nice ctd rattle.when she starts to lose power and pull over to the side of the highway,it is a lot quieter at idle.are you familiar with the fuel control actuator? anybody??

 

problem solved!!! a fuel injector tube fitting was backed off. 15/16 nut somehow backed off. it explains the problem pretty good.engine was ok when cold.as the temps came up,heat expansion opened the fitting,causing the spray pattern to go out of sync.after engine temp. peaked. as temp.came back to normal,the fitting resealed and the engine was fine until the cycle started over again. the nut was retorqued,end of problem. thanks for info guys,just something else to check if you ever have an inconsistant powerloss.

 

dieseldemon17


did your truck act up at any ambient temperature? or just in cold weather?

thanks, chris

 

the ambient temp. did not seem to matter too much.i guess the colder it is,the longer it takes for the engine temp. to peak. after that ,everything went downhill.it just got worst each day and i just knew that something wasnt right.brought to a good mechanic and luckily he found the problem.good luck!!!