I have an 04 cummins here at the shop, it is doing the strangest thing, Ive had it in the shop for two days, I keep it 65 in the shop and this truck will not start! no smoke, no offer, just crank away! plug it in for 20 minutes and it will start immediately! transfer pump is working and fuel pressure is in spec, grid heater working perfectly. It seems electrical to me, why wont it even try to start unless you plug in the block heater? Im not kidding about the time, plug it in for 20 minutes and it starts perfectly every time. I have never seen this before on any diesel, any thoughts? thanks in advance!

 

Can you change out the batteries and try again? I wonder if you don't have a weak battery or two and the ECM is not getting enough juice while cranking to open the injectors.
I think we had someone with a similair problem a week or so ago. A new battery solved the problem.

 

I stock batteries and i can try that, however it cranks perfectly normal and does not crank any faster after plugging in the block heater for a short time, I will load test both batteries and try new ones if they seem even a little down. Thank you

 

I replaced batteries and tried again, still no start. its been 68 degrees in here since yesterday afternoon, i plugged it in for around 20 minutes and it fired right up again this morning. Has anyone heard of this?

 

Do you have a scan tool that you can see what the temp sensor is reading before you try to start it both before and after you plug it in?
A faulty sensor reading to the ECM is all I can think of that has anything to do with plugging it in for 20 minutes.

 

Fuel heater maybe....Just a thought...

DESCRIPTION The fuel heater assembly is located on the side of the fuel filter housing . The heater/element assembly is equipped with a temperature sensor (thermostat) that senses fuel temperature. This sensor is attached to the fuel heater/element assembly.


DIAGNOSIS AND TESTING - FUEL HEATER The fuel heater is used to prevent diesel fuel from waxing during cold weather operation. NOTE: The fuel heater element, fuel heater relay and fuel heater temperature sensor are not controlled by the Engine Control Module (ECM). A malfunctioning fuel heater can cause a wax build-up in the fuel filter/water separator. Wax build-up in the filter/separator can cause engine starting problems and prevent the engine from revving up. It can also cause blue or white fog-like exhaust. If the heater is not operating in cold temperatures, the engine may not operate due to fuel waxing. The fuel heater assembly is located on the side of fuel filter housing. The heater assembly is equipped with a built-in fuel temperature sensor (thermostat) that senses fuel temperature. When fuel temperature drops below 45 degrees ± 8 degrees F, the sensor allows current to flow to built-in heater element to warm fuel. When fuel temperature rises above 75 degrees ± 8 degrees F, the sensor stops current flow to heater element (circuit is open). Voltage to operate fuel heater element is supplied from ignition switch, through fuel heater relay (also refer to Fuel Heater Relay), to fuel temperature sensor and on to fuel heater element. The heater element operates on 12 volts, 300 watts at 0 degrees F. As temperature increases, power requirements decrease. A minimum of 7 volts is required to operate the fuel heater. The resistance value of the heater element is less than 1 ohm (cold) and up to 1000 ohms warm. TESTING [ol][*]Disconnect electrical connector from thermostat . Ambient temperature must be below the circuit close temperature. If necessary, induce this ambient temperature by placing ice packs on thermostat to produce an effective ambient temperature below circuit close temperature. Measure resistance across two pins. Operating range is 0.3 — 0.45 Ohms.[*]If resistance is out of range, remove thermostat and check resistance across terminal connections of heater. The heater can be checked at room temperature. Operating range is 0.3 - 0.45 Ohms.[*]Replace heater if resistance is not within operating range.[*]If heater is within operating range, replace heater thermostat. [/ol]

 

Any codes in it? Also do you have oil pressure both times? And what is the coolant temp with and without it plugged in?

 

Thanks parts/service, i will check those parameters, fuel is a 65 degrees and has been for a few days now, will this still not allow it to start if its not functioning? I do not have a scan tool, still working on that expense, thought maybe someone has run into this before thank you again!

 

I'm wondering if it is a temprature rationality issue between the IAT, battery temp, and the water temp.

if you had a code reader I'd go on a limb and say you may also have a 2509 code that deals with the battery voltage.