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CM2250 running rough after fuel pump replacement - Printable Version

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CM2250 running rough after fuel pump replacement - LuisAndre - 11-27-2017

I changed out a CM2250 fuel pump from the older model to the new one. At idle it seems to run rough. 
Anyone else have this issue?

Fuel lines were changed along with both pumps.


RE: CM2250 running rough after fuel pump replacement - Rocinante - 11-27-2017

(11-27-2017, 04:01 PM)LuisAndre Wrote: I changed out a CM2250 fuel pump from the older model to the new one. At idle it seems to run rough. 
Anyone else have this issue?

Fuel lines were changed along with both pumps.

Could be driveline vibration. Start with simple things and then work your way to more advanced issues.

Start with checking motor mounts, transmission mounts, and vibration dampener. 

Was the calibration updated after the pump was installed?


RE: CM2250 running rough after fuel pump replacement - LuisAndre - 11-27-2017

(11-27-2017, 04:06 PM)Rocinante Wrote:
(11-27-2017, 04:01 PM)LuisAndre Wrote: I changed out a CM2250 fuel pump from the older model to the new one. At idle it seems to run rough. 
Anyone else have this issue?

Fuel lines were changed along with both pumps.

Could be driveline vibration. Start with simple things and then work your way to more advanced issues.

Start with checking motor mounts, transmission mounts, and vibration dampener. 

Was the calibration updated after the pump was installed?

Checked motor mounts all OK. Transmission mounts OK. Calibration update fixed it! Thanks again!!!


RE: CM2250 running rough after fuel pump replacement - burrows_03 - 01-15-2018

Had this happen before kept me wondering ended up it took a reflash to cure it. As well pretty common thing I guess.


RE: CM2250 running rough after fuel pump replacement - RaZoR - 01-16-2018

Having this problem now calibration update didn’t fix it. Is there physical timing for the pump itself? It sounds like it’s tapping at lower rpms


RE: CM2250 running rough after fuel pump replacement - cumapart - 01-16-2018

It’s a commenrail system that builds pressure all the time, timing is 100 control ed by injectors, if the gear has been off the fuel pump they have a procedure on Cummins quick serve to time the pump, if buying a new or recon pump they must likely come with the gear already installed and don’t require to be timed as far as I know, however don’t trust what I say read the instructions on quickserve, Just a warning to any1 replacing fuel pump head or replacing barrels and plungers and roller tappers, MAKE SURE to a-line keyway dowel in the cylinders where roller tappers go in, they should be pointing strait up an down and NOT SIDEWAYS or any other direction for that matter, roller tappets have a notch machined on one side, that is made to a-line with the keyways in the cylinders in the fuel pump block, you can feel dowels when fuel pump head and tappets are removed, you will have to reach down in the cylinders, you can turn the dowels, failure to a-line when reassembling will result in dowel breaking off and fuel pump and possibly engine damage, it is a good idea to inspect camshaft as well when checking fuel pump plungers, pins, and tappets, don’t mix up barrels and plunger pins when taking apart, they are a matched set, Cummins recommends to update to newer 2 piston pump if your engine still has the older 3 piston, some 2 piston pumps came with CERAMIC plunger pins and tappets with brash roller pins, if your fuel pump head is still good these parts can be swapped out for the steel plunger pins and updated tappets, and you will have to be very clean when working with the tight tolerances of this system, if you have a gear of the front gear train, make sure to pin crank and use appropriate timing wedge for your engine, GEAR BACKLASH MUST BE SET CORRECTLY by a mechanic who knows what he’s doing, just my 2 cents


RE: CM2250 running rough after fuel pump replacement - RaZoR - 01-16-2018

(01-16-2018, 02:57 AM)cumapart Wrote: It’s a commenrail system that builds pressure all the time, timing is 100 control ed by injectors, if the gear has been off the fuel pump they have a procedure on Cummins quick serve to time the pump, if buying a new or recon pump they must likely come with the gear already installed and don’t require to be timed as far as I know, however don’t trust what I say read the instructions on quickserve, Just a warning to any1 replacing fuel pump head or replacing barrels and plungers and roller tappers, MAKE SURE to a-line keyway dowel in the cylinders where roller tappers go in, they should be pointing strait up an down and NOT SIDEWAYS or any other direction for that matter, roller tappets have a notch machined on one side, that is made to a-line with the keyways in the cylinders in the fuel pump block, you can feel dowels when fuel pump head and tappets are removed, you will have to reach down in the cylinders, you can turn the dowels, failure to a-line when reassembling will result in dowel breaking off and fuel pump and possibly engine damage, it is a good idea to inspect camshaft as well when checking fuel pump plungers, pins, and tappets, don’t mix up barrels and plunger pins when taking apart, they are a matched set, Cummins recommends to update to newer 2 piston pump if your engine still has the older 3 piston, some 2 piston pumps came with CERAMIC plunger pins and tappets with brash roller pins, if your fuel pump head is still good these parts can be swapped out for the steel plunger pins and updated tappets, and you will have to be very clean when working with the tight tolerances of this system, if you have a gear of the front gear train, make sure to pin crank and use appropriate timing wedge for your engine, GEAR BACKLASH MUST BE SET CORRECTLY by a mechanic who knows what he’s doing, just my 2 cents

Peterbilt did the work, replaced the pump with a new pump. Changed fuel lines. I had the old style pump and they had to upgrade to the new pump style which required changing the fuel lines. It vibrates hard at idle almost feels like it’s doing a regen but it’s not. Engine has tapping noise at low idle and follows the engine into rev up until over 15.


RE: CM2250 running rough after fuel pump replacement - cumapart - 01-16-2018

(01-16-2018, 03:40 AM)RaZoR Wrote:
(01-16-2018, 02:57 AM)cumapart Wrote: It’s a commenrail system that builds pressure all the time, timing is 100 control ed by injectors, if the gear has been off the fuel pump they have a procedure on Cummins quick serve to time the pump, if buying a new or recon pump they must likely come with the gear already installed and don’t require to be timed as far as I know, however don’t trust what I say read the instructions on quickserve, Just a warning to any1 replacing fuel pump head or replacing barrels and plungers and roller tappers, MAKE SURE to a-line keyway dowel in the cylinders where roller tappers go in, they should be pointing strait up an down and NOT SIDEWAYS or any other direction for that matter, roller tappets have a notch machined on one side, that is made to a-line with the keyways in the cylinders in the fuel pump block, you can feel dowels when fuel pump head and tappets are removed, you will have to reach down in the cylinders, you can turn the dowels, failure to a-line when reassembling will result in dowel breaking off and fuel pump and possibly engine damage, it is a good idea to inspect camshaft as well when checking fuel pump plungers, pins, and tappets, don’t mix up barrels and plunger pins when taking apart, they are a matched set, Cummins recommends to update to newer 2 piston pump if your engine still has the older 3 piston, some 2 piston pumps came with CERAMIC plunger pins and tappets with brash roller pins, if your fuel pump head is still good these parts can be swapped out for the steel plunger pins and updated tappets, and you will have to be very clean when working with the tight tolerances of this system, if you have a gear of the front gear train, make sure to pin crank and use appropriate timing wedge for your engine, GEAR BACKLASH MUST BE SET CORRECTLY by a mechanic who knows what he’s doing, just my 2 cents

Peterbilt did the work, replaced the pump with a new pump. Changed fuel lines. I had the old style pump and they had to upgrade to the new pump style which required changing the fuel lines. It vibrates hard at idle almost feels like it’s doing a regen but it’s not. Engine has tapping noise at low idle and follows the engine into rev up until over 15. Is is your truck stock with mandate intact, or are you running a tune with to much timing or perhaps other bad practices, just asking 



RE: CM2250 running rough after fuel pump replacement - RaZoR - 01-17-2018

(01-16-2018, 10:07 PM)cumapart Wrote:
(01-16-2018, 03:40 AM)RaZoR Wrote:
(01-16-2018, 02:57 AM)cumapart Wrote: It’s a commenrail system that builds pressure all the time, timing is 100 control ed by injectors, if the gear has been off the fuel pump they have a procedure on Cummins quick serve to time the pump, if buying a new or recon pump they must likely come with the gear already installed and don’t require to be timed as far as I know, however don’t trust what I say read the instructions on quickserve, Just a warning to any1 replacing fuel pump head or replacing barrels and plungers and roller tappers, MAKE SURE to a-line keyway dowel in the cylinders where roller tappers go in, they should be pointing strait up an down and NOT SIDEWAYS or any other direction for that matter, roller tappets have a notch machined on one side, that is made to a-line with the keyways in the cylinders in the fuel pump block, you can feel dowels when fuel pump head and tappets are removed, you will have to reach down in the cylinders, you can turn the dowels, failure to a-line when reassembling will result in dowel breaking off and fuel pump and possibly engine damage, it is a good idea to inspect camshaft as well when checking fuel pump plungers, pins, and tappets, don’t mix up barrels and plunger pins when taking apart, they are a matched set, Cummins recommends to update to newer 2 piston pump if your engine still has the older 3 piston, some 2 piston pumps came with CERAMIC plunger pins and tappets with brash roller pins, if your fuel pump head is still good these parts can be swapped out for the steel plunger pins and updated tappets, and you will have to be very clean when working with the tight tolerances of this system, if you have a gear of the front gear train, make sure to pin crank and use appropriate timing wedge for your engine, GEAR BACKLASH MUST BE SET CORRECTLY by a mechanic who knows what he’s doing, just my 2 cents

Peterbilt did the work, replaced the pump with a new pump. Changed fuel lines. I had the old style pump and they had to upgrade to the new pump style which required changing the fuel lines. It vibrates hard at idle almost feels like it’s doing a regen but it’s not. Engine has tapping noise at low idle and follows the engine into rev up until over 15. Is is your truck stock with mandate intact, or are you running a tune with to much timing or perhaps other bad practices, just asking 

Truck is stock with mandate intact.


RE: CM2250 running rough after fuel pump replacement - Yairo2 - 04-03-2020

friend put the latest version of the pump actuator

friend put the latest version of the pump actuator

friend put the latest version of the pump actuator