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2001 Ford F-350 7.3L Starting Problem

Discussion in 'Truck & Equipment Repair' started by tom's snow pro, Jan 11, 2010.

  1. tom's snow pro

    tom's snow pro Member
    Messages: 55

    I have a 2001 Ford F-350 with the 7.3 L diesel engine. My problem is that whenever I go to start it in cold temperatures it deosn't want to start for me. At night I usually just plug it in, and it's fine in the morning, but Whenever I go somewhere for more than 3 hours my truck wouln't start without being plugged in. It may just be my engine, but Some friends of mine have dodge cummins, and they could not even plug it in over night and it would start right up? Any suggestions would be awesome? Thanks
  2. nycpsd

    nycpsd Junior Member
    from nyc/pa
    Messages: 27

    A couple of questions for you first, what is the mileage, when is the last time you checked your oil or changed it, what weight oil do you use, how old are the batteries?
    1. If your oil is low you will not be up to the desired oil pressure at cranking speed which is around 500psi to fire the injectors in the motor
    2. If your oil is dirty or is worn out( too many miles between changes) it will make for a harder starting engine.
    3. The weight of the oil in which use use could also be a factor in that a 15w40 oil as opposed to a synthetic 5w40 oil is much thicker as the temperature drops. I use syn 5w40 rottela all year round.
    4. the reason I ask about you batteries is these truck draw alot of power at start up and if you have older batteries they maybe shorted or dead and now you will not have the power in the system to turn the motor over as fast as needed to create the oil pressure needed to fire the injectors as stated in #1
    5. The reason I asked about mileage is I was trying to figure out if your glow plug relay and glow plug may need replacing.

    So what you need is to check your oil condition, age (mileage) if mileage is high or looks extremely dirty I would change it, Would also suggest syn oil
    As for your batteries have them load tested most auto parts stores will do this for free, and if you have a dead or shorted one replace both at the same time.
    And finally the glow plug system if your gpr (glow plug relay) is burnt out you will not have the aid of the gp (glow plugs) to help start the engine.

    I will post instructions on how to test GPR later or you can go to thedieselstop.com which I am also a member under the same user name as I now have to go to work. hope this helps you out.
  3. bry03

    bry03 Junior Member
    Messages: 26

    its needs a relay, or glow plugs. do relay first...
  4. nycpsd

    nycpsd Junior Member
    from nyc/pa
    Messages: 27

    Just giving him other things to check out as I do not know how other people maintain their vehicles so I would rather cover all bases than to just state that this may be his only problem, replacing the GPR is not the fix all for hard starting.
    Last edited: Jan 11, 2010
  5. Mark Oomkes

    Mark Oomkes PlowSite Fanatic
    Messages: 10,417

    While this is all well and good, this is like telling someone to do an engine overhaul when all they need is a set of spark plugs.

    Replace your glow plug relay.

    If that doesn't help, then go on to the glow plugs themselves.

    Then start with the laundry list above.
  6. cretebaby

    cretebaby PlowSite Veteran
    Messages: 4,162

    You're right, but that is most likely what it is.

    The thing that the OP stated that makes me wonder is that it won't start 3 hours later.

    If the truck has been warmed up to normal operating temp it should not cool off in 3 hours.
  7. nycpsd

    nycpsd Junior Member
    from nyc/pa
    Messages: 27

    Just trying to give a little insight on general

    Maintance and diognostic but if you just want to
    Throw parts at it by all means be my guest.
  8. Mark Oomkes

    Mark Oomkes PlowSite Fanatic
    Messages: 10,417

    I had that with the first one I had go bad, didn't make sense to me either.

    But after:
    checking my oil,
    changing my oil
    changing my oil again because I didn't use 5W40
    checking my batteries and then replacing my batteries
    checking my mileage and finding out that my GPR was weak;

    I changed that out and BAM, problem went away.

    Great, another newbie with an attitude.

    Like I said, your advice is not incorrect, however, it is overkill. You always, always, always start with the simple stuff and then get more complicated. Which I guess a check of the oil level is the easiest, but if the truck starts fine within the first 3 hours, it probably isn't oil level or dirty oil or low batteries or oil weight especially if he either just started having the problem or BECAUSE the problem goes away when he plugs it in.

    Which means either the GPR is weak and\or his glow plugs are weak.

    But since I try to follow my own advice, I would start with the GPR and then GP's.
  9. nycpsd

    nycpsd Junior Member
    from nyc/pa
    Messages: 27

    Test the large post the is connected to the battery for voltage should be around 12 volts
    When you turn the key test the other post it should be close to the post connected
    To the battery post voltage. If not relay would suggest a stancor relay donot plug in truck before test
  10. tom's snow pro

    tom's snow pro Member
    Messages: 55

    I am leaning towards checking the GPR, because I have 223,000 miles on this truck!
  11. tom's snow pro

    tom's snow pro Member
    Messages: 55

    Also Thanks for all the imput!
  12. bry03

    bry03 Junior Member
    Messages: 26

    It could cool off within 3 hours of if its cold enough outside. Change the relay, they can be picked up for around $20 at napa, do not go with the overpriced ford unit. As was said, simple things first. The glow plugs draw 10 amps a piece, I have seen relays that will put out voltage, but if the contacts inside are corroded they can't pass enough amps through. I've also seen cases where the relays stick on because of corrosion and wipe out the glow plugs.

    Also, do not run Rotella in these engines. When we rebuild 7.3l heui injectors, we find the most wear on injectors where the engine had been running Rotella. The additive package breaks down prematurely with a heui system.
  13. babs2972

    babs2972 Junior Member
    Messages: 23

    Try going to powerstroke.org and ask there. i got a lot of questions answered there. good luck!
  14. cretebaby

    cretebaby PlowSite Veteran
    Messages: 4,162


    SO......what do you recommend?
  15. bry03

    bry03 Junior Member
    Messages: 26

    10 deg or so is all it would need to cool off enough where an engine with marginal injectors or a marginal hpop (high pressure oil pump) would not start well without the aid of glow plugs.

    As far as oil, we run Cenpeco or Mobil in everything. We've also run Harvester without problems. Basically anything but Rotella.

    Also, to the original poster - Does the truck smoke when you're cranking it and its not starting? If yes, guaranteed gp controller or glow plugs.
  16. Drew2010

    Drew2010 Senior Member
    Messages: 216

    Yup. I would try the relay for sure. For 20 bucks or so you cant go wrong. And if you have access to a VAT (volt amp tester) you should load test the battery. I use a VAT 40 made by Sun. The batteries should be 12.6volts fully charged. test one at a time. I pull 200 amps for 15 seconds. The VAT 40 has a carbon pile load to do this. When your done check the voltage again. If its above 9.5 volts then your fine. If its below its bad. Usually if its good it wont be near 9.5v If its bad it will usually be like 4 volts or so.

    Like i said do this if you have access to a VAT. lol.
  17. T-MAN

    T-MAN PlowSite.com Addict
    Messages: 1,363

    Or a simple carbon pile tester LOL, works well too pumpkin: