Trying to help a friend with her 2004 Dodge Ram 2500 2WD 5.9 HPCR Cummins.

Cold start/no start issues.

I’m new to Cummins so please bear with me! I’ll try to explain as much as I can and hopefully someone can point me in the right direction to save her money!

250,000 miles, no problems ever.

Recently cold weather has seen poor start/no start and it seems to be many folks here in Ontario have had starting issues of late.

Temperature here has been hitting lows -25 C, -5 F for the past few weeks with highs of about -10C, 5 F

Checked block heater. It works. Engine does get warm within an hour.

Checked Air Intake Heater. Works. But…one day while checking, volts from ECM to both relays read only 3.5V. That day, truck was in the garage out of the cold with a space heater underneath the engine.

Changed fuel filter. Housing did have fuel in it when drained.

Before putting in new filter, turned on key and fuel was coming into the housing.

Left truck outside, plugged in overnight. Was -23 C and truck started in the am, no problem. Did not drive it, left it there plugged in until afternoon and it would not start.

Started truck one evening after being plugged in. Truck went to store to get fuel conditioner/anti-gel stuff. Started when she came out. Drove the truck home. Shut it off. It would not start 30 mins later.

Starting seems intermittent.

Turns over fine. Always at least 150 RPM as charger is put on batteries at night.

Would not start last night after being plugged in all day.

Unplugged FCA and tried. No Start.

Gave it a small shot of ether. Started within 5 seconds.

Notice that when cold start light comes on for only 2 seconds, the truck will start. If the cycle runs more than 2 seconds, it doesn’t start.

Tested the heater elements and they get 12V’s and they get warm. Power to them cycles in sync with what the dash light is doing, so no issues there I believe.

There is 12V going to fuel heater in the filter housing, but I haven’t checked for continuity in the heater itself due to hard to get test probes in there.

There is one code stored. P0480 for the fan clutch. I have not unplugged it and tried starting it. Could that cause a no start?

What to check next? I’m assuming these things:
1) If truck starts with ether, there’s no issue in fuel getting from tank to lift pump to filter housing and on to CP3
2) If truck starts with ether, crank and cam sensors are working and in sync
3) Unplugging FCA did nothing, so solenoid and pump ok? Or can these work intermittently?
4) If truck starts with ether, fan clutch is not an issue for no start.
5) Injectors are original as far as we know. She bought the truck with 100,000 miles on it in Texas and hasn’t done anything to it aside from some maintenance…but when I asked her the last time she changed her fuel filter, she thinks never.  She`s put 150,000 miles on it.

Suggestions on where to go next are appreciated. I’d like to check return fuel from injectors etc, but that means money spent and some frozen fingers so hoping maybe someone has had success with this in other areas.

Thank you!