Cold Start Issue

[JPENNER79]

Hello I’m wondering if you can help me out. I have a 2002 Dodge Cummins 24V. Cold start issue. I checked fuel pressure going into injection pump and I'm at 16psi. Wide open throttle it drops to 11psi. So all good there right. What the issue is at -10 celcius it won't start but if I plug in and leave over night it starts no problem. My intake heater is working as the intake elbow is really warm. So it's a cold thing. When I tried starting at -10c without being plugged in I cracked fuel lines at injectors and no fuel would come out. But... next day when I plugged in she started right up no issues. Seems like when the eng block is warm it seems to hold prime but when it's cold it doesn't. I read somewhere that possible low oil pressure could prevent the injection pump from sending fuel to injectors. Any ideas? 

[Mopar1973Man]

How many miles on the truck? 

 

How much blowby do you see from the crankcase vent are you venting oil too?

[JPENNER79]

I’ve got 370,000km. I have some blow by. I have a hose hooked up to the blow by but it drips what I thought would be normal. Maybe a quarter size on the driveway overnight. This after running the truck for 10hrs. 

[Mopar1973Man]

I'm looking at the fact the warmth is the factor. It like your compression is lower why I asked about the blow by. It could be the injectors are getting pissy and the droplets are just to big to ignite in the extreme cold. With 229k miles if those injectors are stock they very well could be wore out. 

[JPENNER79]

Would low oil level cause an issue with these? 

Whats a set of injectors worth? How would I go about testing them? Thank you for helping. 

[Mopar1973Man]

6 minutes ago, JPENNER79 said:

Would low oil level cause an issue with these?

 

Well low oil will cause excessive ring wear and then create the blow by. Typically excessive blow by will push oil out the vent tube. 

 

Good example of excessive blow by.

[JPENNER79]

Lol ya nothing like that. Only reason I ask and I’m embarrassed of it is because I just had to add 4L of oil. I run full synthetic oil and have been doing services every 10,000km. This is the first time it’s been this low on oil and it’s due for a service. 

[Mopar1973Man]

You are actually good till 12,000km (7,500 miles) that is stock service interval from the owners manual. 4 Liters is quite a of oil to be down. The range between full and add is about 2 liters. 

 

Basically, you need two things good strong compression and fine atomized fuel to start in the cold. If your short on one or both then starting becomes a challenge. I would have to say most likely the injectors being the mileage. Then your blow by is not venting large amounts or blowing oil out so I would hold to the thought of injectors just being worn out. 

Edited February 20, 2018 by Mopar1973Man

[JPENNER79]

Okay, thanks for your time. I will look into the injectors. 

[Dieselfuture]

9 hours ago, JPENNER79 said:

I checked fuel pressure going into injection pump and I'm at 16psi. Wide open throttle it drops to 11psi

WOT should be above 14 but that  has nothing to do with your issue. 

 

9 hours ago, JPENNER79 said:

I cracked fuel lines at injectors and no fuel would come out.

I believe you should have fuel coming out so you possibly looking at some leaks, or a weak lift pump. But honestly VP should pull its own Fuel and work okay idle without a lift pump, don't believe it's recommended for very long time. So back to losing Prime issue. Is fuel system all original. 

 

9 hours ago, JPENNER79 said:

I read somewhere that possible low oil pressure could prevent the injection pump from sending fuel to injectors

That's on a Ford. Although I suppose if oil sender didn't register pressure it may not let you start it as a safety feature. 

Any other issues of codes

Edited February 20, 2018 by JAG1

[JPENNER79]

Truck has a fass drp lift pump on it and a reman VP44. I’m not too sure how old the reman VP44 is.