Heavy Equipment Forums Heavy Equipment Community

How to bleed fuel Pump

dcara ยท 2012-03-03 18:35

Ran my Komatsu D31s16 loader out of fuel and now can't get it started. Wore out freshly charged batteries today trying to start it. Hope I just need to bleed the fuel pump but not sure what's what on the fuel pump. Below are links to a couple pics of the fuel pump. The fuel line comes into the bottom of the the assembly that has a knob on it in the lower left of the picture. Not sure what the knob is for though. There is also a slotted screw behind the throttle cable under the right most cylinder fuel line. Any suggestions are appreciated http://i20.photobucket.com/albums/b249/dcara/100_0225.jpg http://i20.photobucket.com/albums/b249/dcara/100_0224.jpg

Replies19
  1. #1tuney4432012-03-03 19:09

    That knob has finger grippers on it which tells me you need to first loosen it counter clockwise,then it will most likely raise and you need to pump it.It's your filter priming pump I'm sure,but you also need to find and open your bleeder screw which is probably hiding under all that black gunk which you need to clean off.Once all the air bubbles are gone from your pumping,tighten the screw and give it a couple more pumps till you have a real stiff last pump,close it down and it should start.If it doesn't your going to have to purge the air out of your injection pump.

  2. #2stray cat.Inc2012-03-04 00:55

    That knurled knob is the fuel priming pump, the bleeder is that slotted screw, loosen the lock nut, before you try opening the bleeder. Pump until you have no bubbles coming, it will take awhile. After you have bled the air out, you will possibly have to loosen each of the fuel injection lines, and keep pumping with the fuel injection pump in the shut off position, this will purge the air out of each plunger and barrel. When you loosen each of those nuts on the injection lines on top the injection pump, wiggle the line you loosen a bit, so the air can escape as you bleed each line. Good Luck

  3. #3tuney4432012-03-04 03:23

    Is there an echo in the room ????

  4. #4thepumpguysc2012-03-04 08:11

    1 thind to add.. where the fuel inlet line connects to the supply pump, under the hand primer,there is a filter inside the bolt. bet you dollars to doughnuts its clogged. Just unscrew the filter w/ a wide blade screwdriver, clean and reinstall. DO THIS FIRST, before trying to bleed.. your still going to have to bleed the system but atleast you know your going to get fuel. Good Luck.

  5. #5dcara2012-03-04 08:42

    Thanks folks. Great info. I look forward to trying to bleed and start it today with freshly charged batteries (again) Stray Cat- What did you mean by "and keep pumping with the fuel injection pump in the shut off position" ? The only fuel shut off I know of is the one coming out of the fuel tank.

  6. #6stinkycat2012-03-04 15:30

    With throttle in the shut down position

  7. #7BlazinSS9342012-03-04 17:17

    Also make sure you have plenty fuel in the tank. I can't tell you how many guys I see spinning their tires tryin to purge air out of the fuel system. Because they think 5-10 gallons is enough to get going.

  8. #8thepumpguysc2012-03-04 17:40

    FYI> you do NOT want the throttle in the shut-off position when bleeding the system.

  9. #9Hutch2012-03-04 18:11

    When I worked in the mines we didnt have time for pump priming so we filled the fuel filter with fuel, removed the fuel cap and inserted a air line, sealed it with a rag, and presurized the tank. It worked every time. In hind sight we should have used an inert gas instead of compressed air. This may not be the exceptable way but i never was one to follow the rules............

  10. #10buckfever2012-03-04 20:13

    We did this a few times on our GMC dump with a detroit.

  11. #11dcara2012-03-04 21:22

    Got it started. Thanks folks

  12. #12czarinaB2012-03-05 05:56

    Thanks for the post. I just started the engine.

  13. #13dcara2012-03-05 14:21

    Cool idea Hutch. I often have a tank of air with me for various reasons and so this is yet another reason to add on board air to my truck.

  14. #14detroyt2012-03-14 19:24

    I'm new. thrird post.....

  15. #15jeeper3502012-03-16 00:34

    I have a 2000 case 90xt skid steer, does anyone know if it has a air bleed valve? Also what the pump primer might look like? I took banjo fitting off above fuel filter and it squirts fuel there, from the low pressure pump on block? Dont know if the highpressure pump is working... same situation ran low almost outa gas think i have air in system. can I lossen lines above injectors too bleed it?

  16. #16thepumpguysc2012-03-16 05:28

    Trace the fuel inlet line TO the injection pump and check for flow there. Make sure the shut down lever is in the run position. Put the throttle in the wide-open position. Bleed lines AT THE INJECTORS. should fire right up.

  17. #17jeeper3502012-03-16 22:20

    Thanks pumpguy... opened the banjo fittings at the injectors (think they are the return lines?) on two of the easiest cylinders to get to. 2 6second cranks got pretty much all the air out.. the third 6 second crank had it blowing smoke and sputtering.. 4th crank fired and smothed out in about 2 seconds. Working perfectly again.

  18. #18jeeper3502012-03-16 22:22

    oh and do you have to make a certain amount of posts on other threads in order to post your own message?

  19. #19thepumpguysc2012-03-17 09:56

    ALWAYS happy to help.. yes, I think its 3.