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My 87 K5 Wont Start!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by derek2002, Jan 1, 2001.

  1. derek2002

    derek2002 1/2 ton status

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    Alright -

    Here is the dilema.... On October 3, 2000 I bought a 1987 K5 w/ a 350. The day before I picked it up, the fuel pump and strainer was replaced by a local garage. From day one, I felt like it might take a while to start, but thought it was just in my head. I drove the Blazer home, around the yard a few times, and that was all. One day I left the ignition on and the battery went dead. The next day, I hooked up the jumper cables backwards (on accident - what would this have an effect on?) and then corrected it and proceeded to attempt to start the K5. No such luck - just cranked over. I havent touched it until a couple of weeks ago. I tried to start it again, but still nothing. I figured that maybe the gas lines were frozen. Soo..... today, I pulled it into the garage and warmed it up. It will fire right up for a second with a little touch of starter fluid, but then stall. The fuel pump isnt kicking and the relay seems to be bad. I tried jumping a hot wire directly to the fuel pump and still nothing. Does it sound like a fuel pump problem?

    If it does, how do I get the pump replaced? I can do the work myself, but there is a warranty from the shop on PARTS ONLY. Will they just replace the part, or do I have to pay them to do the work. Also, can I just take the part off and bring it in, or will I have to have it towed? Will it make a difference that they didnt do the work for me?

    Let me know what you guys think!!

    Later,

    -Derek
    1986 3/4 Ton & 1987 Blazer Project
    <A target="_blank" HREF=http://www.4chevy.com>http://www.4chevy.com</A>
     
  2. NYC K5

    NYC K5 1/2 ton status

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    hooking the jumper cables up backwards on a car with a computer is a big no no. there is a very good chance you fried the computer which means your fuel injection is worth [censored]. same thing happened to a relative of mine on an 90 crown victoria. it cost like $300 for a new computer
     
  3. fr8train

    fr8train 1/2 ton status

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    Use a fresh battery. Turn the key to the "accesory" position( the one before its supposed to turn over). There is supposed to be a "click"( pump relay) and the sound of the pump priming( humming sound from the rear of your truck). If you dont hear any of this it can be your problem. If you hear this then try replaceing your inline fuel filter( on the passenger side frame rail).

    Replace the fuel pump is time consuming but it can be done by you. It involves taking the skid plate( if so equipped) off. Then dropping the tank down using a floor jack. The pump is located on the sending unit that is in the tank. For more detail use the search feature in the forum or get a Chiltons manual, or wait a few more hours and I can post more about it if someone doesnt ( sorry man, food is good).
     
  4. derek2002

    derek2002 1/2 ton status

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    The computer isnt fried - the truck will run. It just quits when the starter fluid runs out.

    The battery is fresh and I know about the fuel pump kicking on in the accessory position.

    I can take my gas tank off - I dont need instructions. I have tested my fuel pump as I have indicated in my first post - I am just wondering if I have done it correctly.

    Later,

    -Derek
    1986 3/4 Ton & 1987 Blazer Project
    <A target="_blank" HREF=http://www.4chevy.com>http://www.4chevy.com</A>
     
  5. northgate

    northgate Registered Member

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    Your fuel pump should turn on for approximately three seconds when you turn the key to the 'on' position. If you cannot hear the pump run you should check to see if your fuel pump relay is being turned on by the computer. The relay is only energized for that three second interval at key on--or when the computer receives a tach signal from the ignition control module. I have seen ignition modules fail in this manner before, where they will allow spark to the plugs but not send its signal to the computer to fire & time the injectors. If you can hear the fuel pump run when you turn the key on, check to see if you have fuel pressure. You can do this by removing the fuel inlet line to the filter and running some hose from it into a pail (this won't tell how much pressure, but it will let you know if there is any fuel delivery). If you have fuel, then your problem is localized to the ignition module or computer. If you don't have fuel, it may be the pump or computer. There is a fuel pump prime wire that you can apply power to to bypass the relay or probe with a test light to see if the computer is turning on the relay to turn on the pump. I don't have my wiring schematics or locators handy so I can't tell you exactly where this wire is but I can check it the shop tomorrow and get back to you on this. Computers are relatively inexpensive, and cheaper yet if have a wrecking yard close by. Modules aren't too expensive either, and if you want to throw one at it and it doesn't fix it, you can least have a spare. Then if your'e out in BF Egypt and you really need one, you have an extra.
     
  6. HarryH3

    HarryH3 1 ton status Author

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    Just because the engine runs on starting fluid doesn't mean that the computer is working. It just means that the ignition system is working. You don't need any other fuel for the engine to run a few seconds when you spray the ether down the intake. If there's spark, the engine will run until the ether fumes are gone. (Don't use too much of that stuff! It detonates so hard that it pounds the hell out of your pistons).

    You should be able to hear a faint buzz from the fuel pump when it's running. If it doesn't run, even when you've applied 12 volts directly to it, then something is wrong with the pump. [​IMG] Getting that sucker out is a PITA!

    <font color=black>HarryH3 - '75 K5</font color=black>
    <A target="_blank" HREF=http://ThunderTruck.ColoradoK5.com>http://ThunderTruck.ColoradoK5.com</A>
     
  7. Chili 87 K5

    Chili 87 K5 Registered Member

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    My first, least expensive thing to try would be the fuel filter. This is never a bad idea on older vehicles with uncertain service histories.
     

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