03 cummins 4x4 cant figure out what is wrong with it. sometimes it will surge and some times it wont so it has to be electrical right?
the trans was just gone through lift pump was just replaced.
can any help?????

 

so today i went and took the sensor of the back of the cp3 pump and cleaned it out put everything back together and fired it up and still surged has anyone else had this problem i cant be the only one.

 

Did you check the codes?

https://www.dieseltruckresource.com/...s-t224833.html

I'd check the connections at the map sensor and the rail pressure sensor. Clean and replace.

Wash the engine bay lately?

 

i just had the computer flashed because i had a bullydog on it and it was pullin a p0602 code got that off of truck by dealer their were no codes untill i pulled the p0483 fan clutch code might be a different problem???
engine is pretty clean. all the connecters are on and none of the pins are bent. the thing that gets me is that it will come and go but it has been doing it alot and i cant get it to stop. but the weather has been kind of crapy here so i dont know??????

 

Air in the fuel would cause this. Find the fuel return line and when the engine is surging put it in a can/bucket and look for air. Also internal parts for the fuel pump maybe getting loose.

 

I've got the same light surge but at a very slow creep and a roughness in park when engine RPMs are slowly brought up from idle at approx 1100 to 1300. Its the worst at around 1200 ish then smooth the rest of the way up. I'll check the connectors since I just put my new F1s in and I was in a hurry to get finished up when that part came around...Also, not to hijack the thread, but I changed my injectors last week because I had a large amount of smoke at idle and figured that since the truck has around 180,000 mi. they were likely getting sloppy. New injectors didn't fix it tho, and im at a loss now as to whats causing the problem. So does anyone have any ideas? They could be related I suppose but I'm no diesel engine expert.

 

By surging do you mean the engine will race up on it's own....like a 1000 rpms or so? If thats the case the FCA will need to be replaced, had that problem with mine.

 

No. Mine is more like a lope when you come to a stop. The tach doesn't even seem to really move when it does it. And the high idle thing 1100-1300 is just a roughness or vibration at that range of rpms. I have tried everything I know to try to do it when in gear and rolling and I can't duplicate it except when sitting still in park or neutral.

 

mine drops to about 450 to 500 then the rail presure goes from about 6000 to about 14000 at a stop.

 

try getting under the truck and look for signs of leakage coming from the top of the fuel tank. I originally thought the oil on my fuel tank was spin-off from the transfer case or universal joint off the axle. You could be pulling in air into the fuel line at the tank if the sending unit is rusted out.

 

i will look but the dealer just replaced the lift pump to the in the tank one but that does not mean that the dealer can do it right!!!!!!
the truck came out of texas it has only been in wisconsin for about 4 months.

 

dont see any signs of anything leaking. there is no rust under this truck at all.

 

Hmmm, let us know when yousolve the problem.

Mike

 

so the problem is not solved yet but it is not surging not sure why it stopped it jus got realy cold aroud 50 degrees and not so humid. i am not sure if the humidity would have anything to do with this problem or not??? when it starts back up is when i stop driving it nice and get on it and put the pedal all the way to the floor??? would that be the throtle position sensor???? but if it was that wouldent it do it all the time???????
i am lost right now and have no clue which direction i should go in
can anyone help at all????????
please??????????

 

it just started doing it again yesterday when i was pull a 25' inclosed trailer that was loaded down.
is there any way it could be the throtle position sensor???

it is not the fca i barrowed mybrother and put it in and got no results.