89 sierra 5.7 no start

Discussion in 'Engine Performance + Maintenance' started by 001pewter, Apr 20, 2019.

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  1. 001pewter

    001pewter Newbie

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    My 89 sierra won't start without priming. It set up awhile and I got it running again with a new fuel pump. After that I replaced the clutch and now it won't start without priming. I read the oil pressure switch has something to do with the fuel pump relay, I replaced the one on top but that didn't help. I can't tell if it's spraying fuel but after trying to crank it there's gas on the injectors. Any help would be appreciated. Tia.
     
  2. evilunclegrimace

    evilunclegrimace I'm Awesome

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    Are you sure that when you reinstalled the bell housing that you did not pinch any wires?

    Start with the Basics . Does the fuel pump run when you turn the key on?
    Do you have Spark?
    Jumper the Fuel pump relay and see if the truck will start.( there is a test lead at the relay)
     
  3. 001pewter

    001pewter Newbie

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    I don't think any wires were pinched. I can't hear the pump, something in the dash turns on when the key is on and I'm trying this by myself. I haven't checked spark, I assumed that if it runs when primed it's getting spark, that maybe wrong.

    How do I jump the fuel pump relay? Thanks for the help.
     
  4. 001pewter

    001pewter Newbie

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    Took a video while cranking, only a little amount of fuel comes out of the injector. Tried jumping from battery to fuse holder, as described in another thread, and nothing.
     
  5. PlayingWithTBI

    PlayingWithTBI Desert Old Guy

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    ^^^ What he said. This will tell you if your relay is working or not. The relay is on the firewall on the passenger side next to the main power terminal blocks under the plastic cover (if it's still there).

    When you turn the key your fuel pump should run for ~2 seconds. If you don't hear it running, or when you bypass the relay, then check your connections including cleaning the ground next to the fuel sending unit on the frame.


    Did you take a timing light and shine it on the injector while cranking? A flashlight pointed behind the injector will work also. You should see a cone of fuel being sprayed with no dripping.

    When you changed the fuel pump did you change the filter too? Put a pressure gauge on it, should read at least 11psi preferably 12 - 13.
     
  6. 001pewter

    001pewter Newbie

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    I checked the voltage at the pump while turning the key, it got over 12. Took the pump out and hooked it up to a battery and nothing. Looks like the 5 month old pump that ran for maybe 10 mins is already dead.

    Thanks for the help guys
     

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