What is pump sound from dash when key is turned on?

[Terry D Waters]

On my 04 Cummins Ram there is a sound like a pump running for 5 seconds or so when key is first turned to run position before cranking. Whatever that is it is activating more often and for longer duration lately. Who knows what that is and what it's about to cost me?

 

[TigreST]

Total shot in the dark here but.... I sorta think the diesel powered machines run a vacuum pump to augment the braking system. Could/should be tied into the brake booster on the firewall. Do you notice any brake performance issues? There was a thread here where a member thought he had one on his gas truck, but was not the case, even though the parts people said his truck (based on the VIN) said it did.

T.

 

[TigreST]

Second shot in the dark: fuel pump sounds. Again not totally sure of the fuel pumps (there are two I think, a tank lift pump and then the injector pump?) The fuel rail would need to be pressurized prior to engine start. That might be the sound you here as the pump cycles. Buddy had a old Cummings 6 Turbo Ram and he researched fuel related issues after his cruise control started tripping off. Seems the Dodge install of the Cummings 6 into the ram was not to Cummings spec which was related to fuel line size restrictions that lead to system heating which caused lift pump failure or some such. He had the complete fuel system replace prior the the warranty running out (friendly service manager at the local dealer). This was a very costly fix if you had to do it off warranty!

T

 

[JohnnyMac]

Third shot in the dark... I believe a short time after you shut down, your HVAC vents close. When you wake the truck up by turning the key, the vents return to Whatever you have them set at. If your vents are hanging up, maybe the motor or gears are making the extra noise?

 

[Terry D Waters]

Total shot in the dark here but.... I sorta think the diesel powered machines run a vacuum pump to augment the braking system. Could/should be tied into the brake booster on the firewall. Do you notice any brake performance issues? There was a thread here where a member thought he had one on his gas truck, but was not the case, even though the parts people said his truck (based on the VIN) said it did.

T.

The noise sounds like it's on the firewall behind the radio. It's always been there just not every time I go to start the truck. Now it runs even after a short period of engine off.

 

[Terry D Waters]

Second shot in the dark: fuel pump sounds. Again not totally sure of the fuel pumps (there are two I think, a tank lift pump and then the injector pump?) The fuel rail would need to be pressurized prior to engine start. That might be the sound you here as the pump cycles. Buddy had a old Cummings 6 Turbo Ram and he researched fuel related issues after his cruise control started tripping off. Seems the Dodge install of the Cummings 6 into the ram was not to Cummings spec which was related to fuel line size restrictions that lead to system heating which caused lift pump failure or some such. He had the complete fuel system replace prior the the warranty running out (friendly service manager at the local dealer). This was a very costly fix if you had to do it off warranty!

T

My lift pump is in my fuel tank and I believe the high pressure pump on the side of the engine is driven off the engine not electrical.

 

[HemiLonestar]

Total shot in the dark here but.... I sorta think the diesel powered machines run a vacuum pump to augment the braking system. Could/should be tied into the brake booster on the firewall. Do you notice any brake performance issues? There was a thread here where a member thought he had one on his gas truck, but was not the case, even though the parts people said his truck (based on the VIN) said it did.

T.

Diesels use hydroboost for the brakes, uses the power steering pump. Very effective, can be retrofitted to gas trucks.

 

[KeithA]

I don't know what it is but my 04 2500 with the 5.7 hemi does the same thing. I figured it was the a/c compressor.

 

[xdmshawn]

On my 04 Cummins Ram there is a sound like a pump running for 5 seconds or so when key is first turned to run position before cranking. Whatever that is it is activating more often and for longer duration lately. Who knows what that is and what it's about to cost me?

My 2005 1500 5.7 does the same thing. I determined it must be the 6 disc changer in my stereo that is attempting to queue up a CD when o first turn on the key.

 

[Richardenos]

Okay, i get the same type noise. So i popped the hood, and turned the key on, and run around to the passenger side next to the antifreeze reservoir. there is a black vacuum pump that is running, and then it stops. So , i found where the noise is coming from. I just don't know what that is. Maybe some one can clarify what this is.

 

[TigreST]

I’ve notice my 18 RAM Sport CC 4x4 makes vac noise related to HVAC settings on engine shut down. This happens a some moments after the engine is dead. Might only hear it if you s/d then sit and wait. It’s like “ghost in the machine” weird man !