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fuel pump not working *FIXED*

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by muddbudd72, Mar 16, 2004.

  1. muddbudd72

    muddbudd72 Registered Member

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    hey guys
    need some help with a 90 blazer with stock tbi.truck just died. pulled fuel filter no gas when turning over engine. replaced fuel pump with a new GM and relay still nothing.any thoughts, and what is robs tbi trouble guide thanks
     
  2. Confedneck

    Confedneck 3/4 ton status

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    Re: fuel pump not working

    how about the fuse? can you hear the pump running when you turn the key on? does the relay click when you turn the key on?
     
  3. bigburban383

    bigburban383 1/2 ton status

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    Re: fuel pump not working

    In your engine compartment, on the left/middle of the firewall is a relay. There is a wire hanging from it, jump power to it and see if the pump turns on. If it does then the wires are good to the pump. Check the orange wire that goes into the relay, it should be hot. There is also a oil pressure switch (next to your distributor) that controls your fuel pump. Buy a 12v test light. It could be a fuse or a bad relay too. Good Luck.
     
  4. muddbudd72

    muddbudd72 Registered Member

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    Re: fuel pump not working

    thanks for the replies. guess i'll have something to do today. LOL!
     
  5. shaun

    shaun 1/2 ton status

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    Re: fuel pump not working

    Mine did the same it just died and wouldnt start while I was pulling some one out. It ended up blowing the epcm fuse in the fuse box. Now I have to figure out why I keep blowing them.
     
  6. BigDummy89K5

    BigDummy89K5 Registered Member Author

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    Re: fuel pump not working

    well when you open the line any where,like take the filter out,you'll never get fuel.little safety switch[don't want to have a fire do we] /forums/images/graemlins/yikes.gifa good ground is needed too.good luck /forums/images/graemlins/waytogo.gif
     
  7. R72K5

    R72K5 Banned

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    Re: fuel pump not working

    have fun droppning tank /forums/images/graemlins/laugh.gif
     
  8. medic_205

    medic_205 Newbie

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    Re: fuel pump not working

    I just had the same problem only a month ago. I also have a '90 Blazer w/stock TBI, anyway... My first suggestion to you is to go buy the Chilton book for your truck it will help you trouble shoot many problems and most of the mechanics that I have gone to with some problems they end up going to my book when they start scratching there head, it also helped in this problem too. First of all you said you pulled the fuel filter and you got no fuel, was that the connector on the tank side or the engine side(clogged filter?) replace it if you dont know, if you have replaced your relay and pump you need to confirm the pump runs, have someone turn the key to the on position while you listen by the fuel tank you should here a buzzing whirl sound if so it is running. If you don't here it running check the fuse to the pump and the ECM fuse, if good check the ground wire and connector coming from the pump it should be going to the frame you can use a test light and a long wire from pos on your battery, is the site where grounded a good ground if so great move on. With the key in the on positon test the tan/white wire going to pump for power if you have power lets move on to where I found my problem. My Blazer would have your same problem and at times it would start, I had replaced my fuel pump last year and knew I needed a new tank also so this time I didn't think I had the time to fix it on my own so I took it to the shop they replaced the relay suggested a new fuel pump and sent me on my way...I still had the problem. So I bought a new fuel pump and found a off road salvage yard with a fairly good tank off a suburban, we dropped the tanks swapped and the other was to big /forums/images/graemlins/doah.gif So I bought a new one put it all together and still had the same problem!!! So we broke out the Chilton book tested all and I mean all the wiring, we found I was getting fuel intermitantly at the filter and when I was getting it there I was getting no fuel at the injectors when we tried to start it and also intermittent spark when we did a spark test. We replaced the Electronic Control Module, which is under the distributor cap (it is a black 1 1/2 x 4 inch looking module.) it solved the whole problem, things are running good. The guy at the salvage yard had one off of a '90 350. I had replaced the distributor last year with a rebuilt one and apparently they don't put new ECM's on them they just test them and if they are good at that time, they put them back on, they are a electronical device and can go out anytime. Test your stuff first, take your old ECM to the part store they might be able to test it if not get a new ECM put it on if it fixes the problem HOORAY, if notyou can return it, check around the salvage places too. Remember to check your fuel pump and ECM fuses after you disconnect and reconnect them they can blow just messing around expecially using a test light! Your best bet it to use a volt meter if you know how or learn. Hope this helps /forums/images/graemlins/waytogo.gif
     
  9. medic_205

    medic_205 Newbie

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    Re: fuel pump not working

    Since my last post I have read many other posts on the discussion board and found that this problem is in common occurance with many folks, you might read some of the past posts also there are some very good tips.

    I have also found other posts with problems I am still experiencing....

    flucuations in RPMs while driving and at a stop, at times it throws a code 43 knock sensor and I have replaced the sensor and wire,

    also my fuel guage reads to the extreme right past full it will move counter clock wise as I burn full from the tank, do I need to check the connection in the dash to the circuit sheet.......advice anyone?
     
  10. muddbudd72

    muddbudd72 Registered Member

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    Re: fuel pump not working

    thanks for the replies. finally got it running. changed out the fuel pump/oil sender,still no go. enginer who designed that needs a good whooping. did like medic 205 suggested and that was the problem. oh well got new fuel pump and oil pressure gage working.
     

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