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Ram diesel cold start problems

Discussion in 'Truck & Equipment Repair' started by Ducati 851, Jan 3, 2015.

  1. Ducati 851

    Ducati 851 Junior Member
    Messages: 10

    Here's a question for any mechanics out there...my 03 Ram diesel won't start in sub 40 degrees day unless plugged in. Previous to this year, would easily start in sub 10 degrees temps. I drive a Freightliner with a Cummins in it, and it will start,albeit hard, when cold and not plugged in. My mechanic friends who work on diesels have no answer. Originally thought it might be a fuel issue, such as lower fuel delivery because of clogged filter.....put new filter in couple thousand miles ago. More of a interesting question quandary than problem, will make sure I plug in. But, why is this happening with no other changes?
  2. Blizzard1980

    Blizzard1980 Senior Member
    Messages: 187

    Grid heater issues?
  3. Ducati 851

    Ducati 851 Junior Member
    Messages: 10

    Don't think so......used to start even without cycling grid heater
  4. leolkfrm

    leolkfrm PlowSite.com Addict
    Messages: 1,980

    how old are the batteries....sometimes the batteries get weak and you dont realize its not turning as fast as it should

    MIDTOWNPC PlowSite Veteran
    Messages: 4,556

    I have a 03 also and you should be able to hear if the grid heater kicks in and see the lights dim a bit. if you cycle the key for a warm up a few times will it still not start.

    you can bump fuel to it by just turning key and letting it go over once. turn off do again. Its injector fuel related not fuel pump related in my opinion.

    if one injector is faulty an 03 will not fire in cold. had this issue myself.
    replaced the injector and it was fine. #2 was faulty

    check for codes? on off on off on with the key. look at the odometer and write them down and google them

    I bought from dieselautopower.com
    good guy.

    I did all the injectors on mine and I still use that truck today. 495 000 kms
    bought it with 80kms 10 years ago.
  6. jhenderson9196

    jhenderson9196 Senior Member
    Messages: 615

    You can confirm a bad injector with a rail pressure gauge or scan tool. The computer requires approx 5000psi rail pressure while cranking to fire the injectors. If one or more have a high return rate it won't make enough rail pressure while cranking. Plugging the truck in warms all components and in some cases closes tolerances enough to mask the bad injector. It also helps the truck crank faster which makes more rail pressure.
    Last edited: Jan 3, 2015
  7. Ducati 851

    Ducati 851 Junior Member
    Messages: 10

    Thx for replies. Injector issues were a thought, but not throwing a code, yet! My mechanic is thinking fuel related, so injector on it's way to being bad sounds possible. Don't think it takes much to make a difference in starting. Our old straight trucks in work have the 5.9 Cummins and they will not start in the cold without plug in. Funny my big 11 litre always starts, and that doesn't even have any grid heat or anything. Thx again, will look at injector issue...
  8. 04trd

    04trd Senior Member
    Messages: 162

    How many miles are on the truck? Does it run fine other than the hard starts? If it does i doubt it will be fuel related. I've got a 7.3 and it has glow plugs and if there is a problem with the glow plugs the truck won't Fire when it's cold. Not sure how a cummins works you guys are throwing the word grid heater, I would look there first.
  9. Cover Guy

    Cover Guy Senior Member
    Messages: 224

    Check the grid heater but you probable need new injectors I had the same issues with one last year
  10. jhenderson9196

    jhenderson9196 Senior Member
    Messages: 615

    IT ain't no stinking Ford! Doesn't have glow plugs and doesn't need the grid heater to start. The heater is there as an emmissions requirement.
  11. SnoFarmer

    SnoFarmer PlowSite Fanatic
    from N,E. MN
    Messages: 9,883

    Then why don't all of them have a grid heater?
    And i think they had them before the EPA?

    It should still start at any temp with out it ,it's just much easer to use it if it has it

    So how do you get it started, if it doesn't start below 40*F?
  12. Ducati 851

    Ducati 851 Junior Member
    Messages: 10

    Grid heater is like a toaster element, it warms the intake air to ease cold starts. With the electronics, truck can still run OK if an injector is not quite up to snuff. I am plugging in to start now that it is cold all the time......THX
  13. jhenderson9196

    jhenderson9196 Senior Member
    Messages: 615

    1: all of them don't have a grid heater because not all diesels are direct injection. Ford and GM are indirect, that's why they need glow plugs. 2: the EPA has been around longer than a Cummins in a pick up. 3: no heavy equipment that uses the 5.9 ( logging, mining, earth moving) has used a grid heater until tier 4 emmissions became law. They all start at -25F without it, but do produce smoke until a little cyl temp is made. Maybe you should stick to snow farming, seems to be your stronger suit.
  14. dieselss

    dieselss PlowSite Fanatic
    Messages: 11,392

    Ford and GM are indirect, that's why they need glow plugs.

    They WERE, not any more. They are direct now...Since 97 on the Ford's and since the dmax on the gm? And they both have glow plugs.
  15. jhenderson9196

    jhenderson9196 Senior Member
    Messages: 615

    No pre chamber? I stand corrected. Why does a DI diesel require glow plugs?
    Last edited: Jan 4, 2015
  16. dieselss

    dieselss PlowSite Fanatic
    Messages: 11,392

    Same reason an idi needs glow plugs. To create heat.
    Some factors include, compression, ignition timing, psi of the fuel delivery, and amount of fuel being injected.
    Some engine manufacturers used a fuel fired intake type heater, and some solely relied on starting fluid.
    While I'm not anywhere near a Cummins expert, fault injectors might be a place to start. As well as your fuel return issue he spoke of.
  17. dieselss

    dieselss PlowSite Fanatic
    Messages: 11,392

    Di.....direct injection, no prechamber
    IDI....in direct injection, prechamber

    Ease of starting as I said.
  18. SnoFarmer

    SnoFarmer PlowSite Fanatic
    from N,E. MN
    Messages: 9,883

    yes, first the op has several threads open on this.
    He needs to get a handle on his fuel return issues.

    He has injector issues because his fuel psi is to low.
    IE he has a leak.
    THX, thanks I've been wondering what that thing was for 38years.
    What was in my post that lead you to believe i didn't know what a grid heater was?

    huummm ,i only plug in if I'm going to use it, and if the temps are below 9*f.


    The EPA was proposed by President Richard Nixon and began operation on December 2, 1970.
    The use of grid heaters predates the epa..;)

    tier4 emmisions.
    NOX,& SOX, egr,dpf, urea,cat, and the grid heater was already in place to be used by the new computers to aid in starting, coming on automatically, no longer being a choice to use it or not to use it by the operator. They also use egr right after start up t0 raise temps, when latter it will be used to lower combustion temps.
    Last edited: Jan 4, 2015
  19. Randall Ave

    Randall Ave PlowSite Veteran
    Messages: 3,593

    Your intake heater needs to work. But you need to connect to a good scanner, run cranking fuel pressure. If it is not up to spec, it will not start. If it is low, you need a special cap for the fuel injector feed rail. This lets you check individual injectors while cranking watching live data. If you find a suspect injector, then you can check fuel return rates. If you have an injector leaking, it may not throw a code.
  20. jhenderson9196

    jhenderson9196 Senior Member
    Messages: 615

    Sno Farmer, tell us all what Cummins engine used grid heaters before the first gen Dodges used them in the late 80s.

    Randall Ave, why do his grid heaters need to work ?