2000 gmc jimmy cranks won't start

Discussion in 'Chevy Blazer Forum (GMC Jimmy)' started by alans, Dec 7, 2013.

  1. alans

    alans New Member

    Hi, my usually very reliable jimmy won't start.I was thinking fuel pump ,but not sure.Here may be a few clues.1) about a month ago service engine soon light came on.It still started and ran fine.2) one day recently ,it started but not as quickly as it always had .It cranked about 15seconds before stating.3) A week ago it did not start and I ran the battery down trying to.The next day it started right up ,I just turned the key.I didn't even have to charge up the battery.I got this used a few years back and I wonder if the security system has anything to do with my problem because I didn't know it had an alarm in it till it went off by itself one day.One other question. When you first turn the ignition key does the fuel pump still turn on for a few seconds ,because I haven't been able to listen for that yet.I'm at home by myself today.I think there is pressure in the fuel system because I pushed in the fitting where you attach a pressure gauge and some fuel shot out.I don't own a gauge thanks any advice will help.Some day I would like to disable the security system since I don't know how it works anyway Alan
     
  2. MAD JAX

    MAD JAX Member

  3. the phantom

    the phantom Well-Known Member 2 Years ROTM Winner Gold Member 1000 Posts

    You can rent for free a pressure gauge at autozone if theres one by you. The 4.3liter requires about 63psi in order to start and 55 psi to run properly. Ive put many fuel pumps in a 99 jimmy I use to have that had the same symptoms your describing. Even though theres pressure and even if you can here the pump it doesnt mean its not the problem unless you check the pressure. Sometime when it doesnt start put jumper cables on it(even if the other battery is good) and see if that makes a difference. The extra power from the jump spins the fuel pump just a tad more usually getting enough psi to start. I had this happen as strange as it sounds. If the pump motor is getting weak it wont spin fast enough(unless jumped) to produce the pressure needed to start but could usually maintain enough to run fine.
    Also if its raining or damp out and it wont start but then is dryer the day it does. This could be an issue with your distributor cap.
     

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