Glow plugs on 2025 Cummins

[teton10]

I noticed on my 2025 Ram 2500 with Cummins that in cold weather (sub-freezing temps as low as 13 degrees) there is no delay between me pushing the start button and the engine starting - same with remote start. The engine runs rough for about 5 seconds then smooths out. It leads my to think that the glow plugs are not warming up. The dealer says that there should not be any delay in starting and that the glow plugs work immediately. Anyone else have this situation or have you heard that this is normal? Definitely different than the 6.7 with grid heater. Thanks

 

[Brutal_HO]

No delay/wait to start is normal.

 

[mbarber84]

I noticed on my 2025 Ram 2500 with Cummins that in cold weather (sub-freezing temps as low as 13 degrees) there is no delay between me pushing the start button and the engine starting - same with remote start. The engine runs rough for about 5 seconds then smooths out. It leads my to think that the glow plugs are not warming up. The dealer says that there should not be any delay in starting and that the glow plugs work immediately. Anyone else have this situation or have you heard that this is normal? Definitely different than the 6.7 with grid heater. Thanks

Cummins is having some issues with the glow plugs causing shorts / short-cycling.

When you attempt to start, are you holding your foot on the brake pedal? Have you tried keeping your foot off the pedal? Any check engine lights or trouble codes ?

 

[NDanecker]

Thermodynamics would dictate it would take time for the glow plugs to reach optimum temperature to help ignite diesel fuel thus starting the combustion cycle (more then a few microseconds which is currently set). IMO not having a delay tied to outside ambient temperature in the ECM is incorrect and probably an oversite. Have you tried adding your own delay? For example, turn on ignition but don't press brake pedal to start?

I currently have a F-450 that has glow plugs. On very cold mornings it adds a delay before engaging starter motor.

 

[teton10]

Cummins is having some issues with the glow plugs causing shorts / short-cycling.

When you attempt to start, are you holding your foot on the brake pedal? Have you tried keeping your foot off the pedal? Any check engine lights or trouble codes ?

The engine starts immediately even if it's sat all night and it's 15 degrees when starting. No delay for the glow plugs to warm and a rough running for about 5-10 seconds. The dealer is saying that the glow plugs are always on but I know that's just not true. I often remote start the truck as it sits under a shed roof about 70 feet from our house. It starts immediately without a "glow plug" delay in sub-freezing weather. i am used to my 2022 and previous trucks with grid heater that delay for a few seconds before cold weather starting.

 

[Msw1382]

Push the start button without foot on the brake. Your glow plugs will kick in and warm for about 10 seconds. Then start as normal

 

[HDFarmer]

I noticed on my 2025 Ram 2500 with Cummins that in cold weather (sub-freezing temps as low as 13 degrees) there is no delay between me pushing the start button and the engine starting - same with remote start. The engine runs rough for about 5 seconds then smooths out. It leads my to think that the glow plugs are not warming up. The dealer says that there should not be any delay in starting and that the glow plugs work immediately. Anyone else have this situation or have you heard that this is normal? Definitely different than the 6.7 with grid heater. Thanks

I noticed that on my 2025 5500 as well, push start without your foot on the pedal and wait, this solves 2 problems. Allows plugs to heat up and charges fuel system which prevent excessive cranking with the known air capture in the fuel filter housing