2004 Cummins long cranking issue.

[Squatch]

2004 QCSB Cummins with a 6-speed.

All of a sudden it's a bitch to get started after it has sat for a few hours.

Once I get it started for the day, it will normally start with only a minor extended cranking session. Say, maybe 1-3 seconds.

First thing in the morning though, it sometimes won't start without hitting a snort of Ether first.

Once it's running, it runs like normal, power is fine, hazes under load like it always has, etc.

It's got pretty new injectors, <50,000Kmiles, new fuel filter, new air filter.

I replaced the lift pump because I could pull it down to 1-2 psi with a load on the truck, with no change in symptoms.

It seems like it starts easier if it's warm out.


Any help is appreciated.

 

[Gravy]

Grid heater maybe

 

[Stix]

That’s EXACTLY what my 05 did when it had a couple bad injectors.

 

[Squatch]

Grid heater maybe

Negative. Grid heater is working.

Should have mentioned that in the original post.

 

[YotaAtieToo]

Make sure the oil doesn't smell like diesel. Loose fuel lines in the valve cover is a common issue.

 

[Squatch]

That’s EXACTLY what my 05 did when it had a couple bad injectors.

The guys that did my injectors last time are adamant that it’s a waste of time to pull them for testing. They want me to bring the truck to them and leave it for a few days, which is a pain as they’re a couple hours away.

They think I have a fuel siphoning issue, but can’t offer any help as to what is the most likely spot to be sucking air.

 

[Squatch]

Make sure the oil doesn't smell like diesel. Loose fuel lines in the valve cover is a common issue.

No fuel in the crankcase. That was a symptom of the last set of injectors I replaced so I was quick to check that here.

 

[Benny]

No fuel in the crankcase. That was a symptom of the last set of injectors I replaced so I was quick to check that here.

What brand and size of injectors did you have installed?

 

[Leadfoot21]

If your last people that replaced the injectors are adamant it can’t be the injectors I’d steer clear of them in the future . Bad “new” parts are the norm in today’s world.

 

[shortbus4x4]

Take it to Dodge and have them make sure the ECM calibration is up to date. I've had several of the early common rails have starting issues, which the old ECM calibration wouldn't set a code for but the new one would. I would probably be checking the injector return flow first to make sure your injectors are good, too much return and you get symptoms like you're describing. If I remember correctly the original ECM calibration wouldn't set a code for it but the new one would.

 

[GLTHFJ60]

If it were an older engine, I'd say you're losing fuel system prime. Leak in your feed/return lines to/from the engine, engine lines, etc.

 

[AlxJ64]

My '06 did this when it went through the first set of injectors and I had them put in. I sold the truck after about 11k miles on the replacement injectors, however during the first 3k miles I had a replacement injector drop out entirely and then a friend bought the truck and he had another do the same since and he's only put about 15k on it himself. They were Bosch NOS injectors, not remans either.

 

[Squatch]

I need to follow up here with the solution.

I let a mechanic/acquaintance look at my heap-o-shit when the starting issue became bad enough that I had to do something.

Low rail pressure, as I suspected, wasn't allowing the injectors to fire. He found the rail pressure relief valve had failed and replaced it.

A symptom I hadn't even recognized was the loss of power. I thought the truck was running fine under load, but with the new relief valve, it's much more powerful.

 

[AlxJ64]

I need to follow up here with the solution.

I let a mechanic/acquaintance look at my heap-o-shit when the starting issue became bad enough that I had to do something.

Low rail pressure, as I suspected, wasn't allowing the injectors to fire. He found the rail pressure relief valve had failed and replaced it.

A symptom I hadn't even recognized was the loss of power. I thought the truck was running fine under load, but with the new relief valve, it's much more powerful.

That makes total sense! I had something similar happen on my Cummins ISB170 when I was first trying to get it running after the swap. I didn't realize that the FPRV had popped and as a result the truck had a rough lopey idle and stumbled on throttle application. I didn't realize it was the valve until I was messing with my fuel return lines and the rail dump hose soaked me.

 

[GLTHFJ60]

I need to follow up here with the solution.

I let a mechanic/acquaintance look at my heap-o-shit when the starting issue became bad enough that I had to do something.

Low rail pressure, as I suspected, wasn't allowing the injectors to fire. He found the rail pressure relief valve had failed and replaced it.

A symptom I hadn't even recognized was the loss of power. I thought the truck was running fine under load, but with the new relief valve, it's much more powerful.

There wasn't a code for that? Will have to keep this info in the back pocket, thanks for following up.

 

[Johnny Longrifle]

Nope, they won't set a code for that. If they have the correct calibration in them, the ecm will recognize too much return flow, and light up the wait to start "glow worm" light. Too much return flow can come from several places, but I have seen several FRPR valves leak. They all get replaced with a race plug. Those will set a code for rail pressure too high, but won't light the CEL.