1999 GMC Yukon 5.7 liter crank no start

Discussion in 'General Chevy & GM Tech Questions' started by jdavis25, Mar 25, 2014.

  1. MrShorty

    MrShorty Epic Member 5+ Years 1000 Posts

    In doing this, can I then assume that this means we know the pump is not getting power while cranking? If we are certain that the fault is because the fuel pump is not getting power, then my next step would be to get out my voltmeter and wiring diagram and see if I could figure out where in the fuel pump circuit there was power and where it was dead.
  2. jdavis25

    jdavis25 Member

    It sounds par for my course haha but I tried a known good relay out of my 1999 k2500 and the brand new battery out of my k2500 as well same problem

    - - - Updated - - -

    From what I know bout these gm fuel pumps is even brand new its like a gamble like 1 out 3 brand new pumps are good I know when I done my pump in my k2500 it took me three different Delphi pumps brand new from car quest till I got it running but I haven't had a problem like this I don't understand it how it starts if I jump start it and then start there on after it Starts on its own with out hesitation on first crank then it sits for a few hours then it needs jump started again but my battery stays charged I can crank it for a good 15-25 minutes til battery goes dead
  3. RayVoy

    RayVoy Epic Member 5+ Years 5000 Posts

    Sorry, your post sounded like a known good relay worked.
    Last edited: Mar 31, 2014
  4. jdavis25

    jdavis25 Member

    Its alright any info helps
  5. jdavis25

    jdavis25 Member

    Well I went to visit family and decided to drive this instead of my other truck and when I got to my home town I went straight to my families business which is a tranny shop and done some teats and did find a bad ground off of my fuel pump and added another ground and had to let it sit overnight to see if it fixed anything and and still no luck on this I am back home only had a Lil bit to look at the truck but just thought I'd share more info as I come across it and did do some searching on identifix and auggested ignition switch module with my symptoms so maybe I'll try to get a used one throw it on and see what happens thanks
  6. RayVoy

    RayVoy Epic Member 5+ Years 5000 Posts

    Ok, you have a truck that won't start, but you drove it to your home town???????????????

    I'm guessing you got it to start by using an other vehicle to jump the battery.

    You drove it to an other town....................................... the fuel pump must be good.

    Buy a new battery...........my 2 cents worth.
  7. silverado002

    silverado002 Rockstar 3 Years 1000 Posts

    This is a tough one. My thoughts are: 1.It will start if you inject ether. That tells me you are lacking fuel so why aren't the injectors firing?
    2. It will start if you jump start to another battery. Could it be that your starter motor is putting such a drain on the battery when cold that it is excessive current drain and the fuel injectors etc. don't have enough voltage/current to fire? The addition of the second battery doesn't add more voltage but does double the current available so the voltage drop to the system may not be as great versus a single battery.
  8. jdavis25

    jdavis25 Member

    I tried my other battery which is brand new out of my k2500 still same problem, but on the other hand I could have something drawing too much voltage and with the other vehicle pushing extra juice I'll pull my alternator and get that tested an engine mechanic at my family shop said he had similar issues and that fixed his so I'll try the alternator first and then starter see what I get thanks
  9. RayVoy

    RayVoy Epic Member 5+ Years 5000 Posts

    The alternator provides the charge for the battery, there would be no drain, from the alt, when trying to start the truck.

    Now, it may not be properly charging the battery, but you seem to have discounted that by using a different battery and getting the same result.
  10. jdavis25

    jdavis25 Member

    Well I finally got back on it and tried a couple more things. I have tried a known good crank sensor tried an extra ground off of my fuel pump, I can hear my fuel pump kick on when first turn key tried to start it with just ground to another truck and tried just the positive to another truck to see if it was a ground or power issue with again no luck going to try blocking return line next to see if my pressure is just leaking off back through the regulator and back to the tank tomorrow and also it doesn't start off jump start anymore ether only to start and its getting harder and harder to start as well

    Any more info helps thanks in advance

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