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1990 Suburban starts, runs fine for 30-45 seconds, then dies. Need Help

Discussion in 'The Garage' started by joey90, Dec 17, 2003.

  1. joey90

    joey90 Registered Member

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    I have a problem with my 1990 Suburban. It has a newer 350 in it with 20k.

    When I go to start it the thing starts up fine, no throttle needed or anything, just turn the key. It'll run like normal for 30-45 seconds then it just shuts off. Doesn't seem like it dies, but rather shuts off, as if you switched off the key. It leads me to believe it may be an electrical problem but I have no idea. When I start it up the check engine light doesn't come on, so I don't know if it's throwin a code or not.

    Any suggestions?
     
  2. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    Check for plugged vacuum line to the MAP sensor. Will the truck run if you give it gas? Once it dies does it start right back up again?
     
  3. joey90

    joey90 Registered Member

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    I'll check that. I give it gas and it revs like normal. I keep it rev'd and it still dies in the same ammount of time. Once it dies it does start right back up again, usually...
     
  4. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    Also check for proper functioning EGR valve.
     
  5. joey90

    joey90 Registered Member

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    how do i check to see if it's functioning properly?
     
  6. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    Start by taking the vacuum line off the EGR valve and then hook a vacuum pump to it and see that it does open. If it is stuck open then you need to remove it and either try to clean it or just replace it. The EGR valve on your truck is operated through an electric vacuum switch so there is also possibilities of the switch being bad also (but I doubt it)
     
  7. Klink K5

    Klink K5 1/2 ton status

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    This maybe your problem.
     
  8. joey90

    joey90 Registered Member

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    Thanks guys, I'll check these tomorrow. Please keep the ideas coming!
     
  9. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    That info is not correct. The fuel pump relay is what gives power to the fuel pump. The pressure switch is there in case the fuel pump relay should go bad so long as there is oil pressure it then gives power to the fuel pump. I would however make sure you can hear the fuel pump cycle for 2 seconds after the key is turned to the on position.
     
  10. joey90

    joey90 Registered Member

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    someone was telling me i could remove the air filter and look to see if fuel was being sprayed, is that true?
     
  11. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    That is correct.
     
  12. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    It could just be a plugged fuel filter. That happened to my wife's old Mustang /forums/images/graemlins/blush.gif I thought the fuel pump had packed it in. It would run for 30 seconds or so and then just die...in no time at all it would fire back up but wouldn't run longer than 30 seconds.

    I installed a new filter and it ran like a charm again.

    Rene
     
  13. big pappa b

    big pappa b 3/4 ton status

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    same thing happened on my old S-10. replaced the fuel filter and good as new
     
  14. K5DRAGER

    K5DRAGER 1/2 ton status

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    Just throwing this out there because it happened to me on my 88 tbi crew cab. I redid the wiring to the alternator, because the previous owner had it all messed up. When I was done I drove to my budy's house... about 10 minutes and messed around for a while. When I went to leave it did what yours did it would run for about 30-45 seconds and just shut off. After alot of trouble shooting and about an hour later we found one of my new wires I had fixed with a crimp/solder type connector didn't make a good connection. I guess that when the computer saw the low battery/ voltage it would shut off the truck. And would only let you restart it if you turned the key all the way to off and then started it. We fixed the wire problem and it started right up and stayed running.
     
  15. joey90

    joey90 Registered Member

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    The Burb is runnin again!

    I didn't have time to check it out myself but my dad fixed it. It was either the fuel pump or the injector relay. Replaced em both and it runs just fine! Thanks alot for all your help guys, it's appreciated.
     

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