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97 7.3 diesel starts hard

Discussion in 'Truck & Equipment Repair' started by Ziob34, Oct 1, 2012.

  1. Ziob34

    Ziob34 Senior Member
    Messages: 182

    got a 97 f350 with the 7.3 getting ready for winter and for some reason its starting hard........what used to start on the first cycle (wait for light and glow plugs to heat up) now takes a good 3 to 4 times through to start. Glow plugs were new last year don't think it is them but could be wrong......any ideas? once its started it'll started up on a dime all day long this problem only happens in the morning when its been sitting all night.
     
  2. Banksy

    Banksy PlowSite Veteran
    Messages: 3,113

    What brand of glow plugs did you use? I've heard the Auto Zone types are known for burning up pretty quick. How new is the GP relay?

    I guess it's also possible that you have an air leak in a fuel line somewhere.
     
  3. Plowtoy

    Plowtoy Senior Member
    Messages: 929

    I bet you have a bad glow plug relay. You can get an updated relay from your local ford dealership that comes with a new wire harness that converts the old style (94-98) to the new style (99-03). I had that problem with my 97 and its quite common. The relay wears out over time and wont allow enough amps through it too the glow plugs
     
  4. FISHERBOY

    FISHERBOY Senior Member
    Messages: 542

    You could change ur oil in the high pressure oil pump, that could help also
     
  5. truckitup

    truckitup Senior Member
    Messages: 256

    I agree with Plowtoy, had a 97 and that fixed the same problem.
     
  6. Holland

    Holland Senior Member
    Messages: 605

    Dont overlook the simple things, is it turning over good? 7.3's like their rpms for cold starts.. make sure your batteries and all connections are good!
     
  7. FordFisherman

    FordFisherman PlowSite.com Addict
    from 06611
    Messages: 1,593

    GPR most likely, just did mine again. Use a fisher or western they last longer than that Napa junk and cost alot less.
     
  8. Plow More

    Plow More Senior Member
    Messages: 172

    Thats not any different than changing the engine oil. Get a volt meter and check the relay yourself. Have someone turn the key on while you check the two large posts on the relay for ~12v. It should also stay on for about a minute in cold weather. You should also hear it click. How many miles on the engine and are the injectors originals?
     
  9. brad96z28

    brad96z28 PlowSite.com Addict
    Messages: 1,526

    True changing the oil in the hp pump that mixes with the regualr oil any way is a big was of time. Also checking to gp realy use an amp meter do not look for voltage is means nothing when checking for amp draw. You can have a bad gp relay that will show 12 v on both sides but is not passing the amps.See it all the time with all types of relays. It should draw around 180 with the correct glow plugs (beru) those are the only brand you ever want to run in them! Any less amps you have bad glow plugs. O to 5 amps bad relay. It takes about 5 min the ck out how the whole system is operating. :mechanic:
     
    Last edited: Oct 1, 2012
  10. Plow More

    Plow More Senior Member
    Messages: 172

    ^^^what he said. You just have to open the box and see what brand they are. Dont use autolites mainly. Another thing to check though is the level of the oil in the HPOP resirvoir. Little allen plug in the top of the resirvoir right on top and in the very front of the engine. Stick a screw driver in there and make sure the level is within about an inch of the top. If not, you may have a drainback issue and cranking the engine 3-4 times could be the hpop priming back up before it will have enough pressure to fire the injectors.



    How many miles on the truck?
     
  11. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,947

    Also. Try to ohm out the glow plugs at the valve cover connector that will tell you if you have a issue under the cover
     
  12. brad96z28

    brad96z28 PlowSite.com Addict
    Messages: 1,526

    If you do the amp draw test at gp solenoid you dont need to waste time doing that.If you have a 180 amps you know they are ALL working. Unless you are getting paid by the hour or something.
     
  13. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,947

    Sorry but how many pple have an amp clamp? Not exactly standard auto tool
     
  14. brad96z28

    brad96z28 PlowSite.com Addict
    Messages: 1,526

    Anyone that wants to fix a vehicle. Same principle with testing a starter or alternator checking volts and voltage drops does not tell amp output or draw.
     
    Last edited: Oct 1, 2012
  15. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,947

    So what happens when you don't have 180,,,,gotta do the ohm test so 6 to 1 or half dozen to the other. Whatever you have, whatever is easiest
     
  16. brad96z28

    brad96z28 PlowSite.com Addict
    Messages: 1,526

    Depends on what you get for amps . Say you had 140 or 160 amp that means you have 1 or 2 out, And that will never even create a hard start problem on one of these systems So you would look elsewhere for a problem. The old non ps engines even 1 being out would cause hard start problems. If you get a 5 or 10 amp reading you replace the gp solenoid, 0 amps ck wiring at the gp solenoid for propper operation wiring checks out change gp solenoid. If you want to ck each gp one at a time the easy way is with a test light at the valve cover connectors.Test light lights gp is good. Its a fairly simple system. I know on the later ones I have had to clear trouble codes after I found the problem for the system to function propperly again.
     
  17. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,947

    Well 1 or 2 might depending upon temp but the op never said anything about smoke. 1 or 2 will cause ruff running. If you had 140 amps your still Gunna ck to see which ones are bad regardless. And how many pple ck the amps on a charging system that's operating and 14.5. If you turn on lights and heater and it drops below specs,,why ck amps alts bad. If alts only putting out 12.5. Why ck amps alts bad. And how many pple on this site, have a test light, dvom, and an amp probe.
     
  18. brad96z28

    brad96z28 PlowSite.com Addict
    Messages: 1,526

    1or 2 being out will not cause a hard start in these temps. If it had a 140 amp draw I would not bother checking them I would want to find out why it starts hard first. Because that wont do it. Changed alot of alternators that put out 14.5 volts but only 25 or 30 amps. As a matter of fact i did one 2 weeks ago on a tundra charging just enough amps to keep the battery light off and had near 14 v running but was getting a dead battery alternaor did not supply enough amps to charge the battery. So I would say mechanics and people that have a clue ck amps.
     
    Last edited: Oct 1, 2012
  19. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,947

    At 14.5 with lights on and heater on high? No way they put out 14.5. maybe at idle with no load sure but I need load ill agree 1or2 at these temps will not be a hard start,,,but will be a smoking start
     
  20. brad96z28

    brad96z28 PlowSite.com Addict
    Messages: 1,526

    Lights and heater dont draw what 15 -20 amps thats not enough to make any kind of a test. Voltage while cranking is something you can go by.That bad alternator did not 14.5 as many alternators I check dont it was around 14v I use a carbon pile load testor to see what the alternator does.Some cars have computer controlled where the voltage is lowered by the computer and has nothing to do with the alternator. Yes might see slight smoke at inital start up with a couple or more out. And the only gp solenoids I have used to replace bad ones have been motorcraft with no problems. I have never tried a plow solenoid that is much cheaper.Might work just as good?