Yukon intermittent no start

Discussion in 'Engine & Drivetrain' started by Jester1023, May 18, 2018 at 9:06 AM.

  1. Jester1023

    Jester1023 TYF Newbie

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    So I just picked up an 04 Yukon last Friday from someone I know who has taken very good care of this vehicle truck has been running great except for one small issue on Wed I got up to go to work only to have the truck crank over but not start I tried 3-4 times until I gave up,I woke my wife to bring me to work made a cup of coffee and figured let me just give it one more try and wholla it started right up,in the meantime I texted my friend who I bought the vehicle from to let him know what happened he asked where was the gas tank fuel wise I told him 1/2 tank so he said to add some chevron techron when I got gas the fuel sensor could be hanging up on me,so I filled it put the techron in and it has been starting with no issues since up till this morning so once again It cranked over but did not start a couple of times I heard the fuel pump kick on so I feel that is working and not the issue but I can be wrong I am pretty much just a maintain guy not a gear head like on Wed I waited about 10 minutes before trying again and sure enough it started right up.so now I am wondering what this could be.

    The pump seems to be priming so I am not sure if there is an issue here I am far from being a mechanic just enough to get by so I am trying to diagnose and pin point some possiblities of what this may be.other than this issue the truck runs like a dream now I cross my fingers every time I go out to start it,my friends Z71 who I bought the vehicle from used to do the same thing till he added the techron so I was hoping that would work his problem worked itself out where as it seems as if though mine goes a bit deeper as this is the second time this has happened to me.

    any thoughts on where I can start to try and diagnose this?

    Thank-you
     
  2. HiHoeSilver

    HiHoeSilver Away! Supporting Member

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    I would start with a mechanical pressure gauge on the fuel rail next time it won't start.
     
  3. Doubeleive

    Doubeleive Elite Member Supporting Member

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    can you clarify the no start issue 1. is the starter going and it just wont fire up. 2. the starter is not going?
     
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  4. Jester1023

    Jester1023 TYF Newbie

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    the starter is going


    the starter is working its just not starting
     
  5. M1Gunner

    M1Gunner Full Access Member

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    Do you know if you have a fuel return line or if it’s a returnless system?
     
  6. Doubeleive

    Doubeleive Elite Member Supporting Member

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    normally the cause is a bad fuel pump then, adding cleaners wont have any effect, what is the mileage? the oem pumps are rated for 100k but will go a bit farther, if it intermittent enough to where it is doing it often a fuel pressure test will reveal it.
     
  7. Jester1023

    Jester1023 TYF Newbie

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    problem solved I just had it to to the mechanic he pulled two codes both related to the alarm which is odd as I have not been using it since I picked up the vehicle maybe a couple of times but not every night but yeah he pulled two alarm codes out of it,I need to wait till Monday to get them cleared out and reset as he does not have the equipment at the shop to do it he will have it back Monday but he tells me the alarm is locking the engine out hence being able to start it after it sits for about 10-15 minutes.At least its not mechanical its A frustrating stupid little thing!

    Thats for all the quick feed back and suggestions!
     
  8. HiHoeSilver

    HiHoeSilver Away! Supporting Member

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    Another passlock doing its job.lol
     
  9. Doubeleive

    Doubeleive Elite Member Supporting Member

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    my experience with the passlock system is it usually the ignition switch, sometimes the ignition housing can be funky as well but not as common, unless he is bypassing it or ordering a ignition I don't know what else would be done. simply clearing a code wont fix anything. the relearn is 10 minutes that anyone can do but the problem will still exist and rear it's head usually at the most inopportune time.
     
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  10. Jester1023

    Jester1023 TYF Newbie

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    While he has it there on Monday I will have him put in a new ignition switch hopefully that fixes the problem.when you say relearn not sure of the terminology but is that why if after it won't start if I come back in about 10 minutes or so it starts this seems to be the common occurrence wed and twice on Friday once in the am and once in the afternoon before getting it to the shop.

    My old man did mention something that kind of makes sense I have a lot of keys on my key ring with my truck keys which makes it a bit heavy he mentioned it could be pulling the keys down with the weight making a funky connection any merit to this in your opinions
     

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