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Fuel Injection Problems

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Depdog, Sep 25, 2001.

  1. Depdog

    Depdog 1/2 ton status Author

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    Well, I am at witts end. I have tried everything I can think of. I am going to pull all the connections and clean them and bolt them back on to see if it helps. Just cant seem to figure this out.

    If the truck has sit overnight it will not crank, the engine will turn over fast and you can hear the fuel pump spool up when you turn it on, but the injectors will not fire while the engine is turning over. If I hook up another battery in line with jumper cables same thing, if I fire up another vehicle and hook the cables to it, it will fire right up. Let it run for just a few seconds and remove the cables and cut it off and it will fire right back up no problem. Let it sit for a couple of hours and it sill still fire right back up. Let it sit overnight and whamo no crank again.

    Its KILLIN ME, aaarrrgghhhh what in the @#^%#$ is going on!

    Depdog

    <font color=blue>Weenie K5, little mods' Small Tires!</font color=blue>

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  2. Thunder

    Thunder 3/4 ton status

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    About all I can think of is your ECM is detecting low voltage and will not open the fuel shut off. Check all the power connections to the ECM. Also I am assuming that your battery and starter is in good shape. If your battery is bad the starter may be robbing all the power and the ECM is detecting low voltage and will not let the vehicle start. Are you getting any troublre codes? Also If you have a scanner with the digital readouts it would tell you how many volts that the computer is sensing and if there is a low voltage problem.

    <a target="_blank" href=http://coloradok5.com/gallery/Thunders-Blaze>http://coloradok5.com/gallery/Thunders-Blaze</a>
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  3. realsquash

    realsquash 1/2 ton status

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    A. What model of Projection is it? Analog? Digital?
    B. Where is the fuel pump ground and the +12V connected?

    You need to measure the voltage coming to the ECU, not at the battery or any other place. You also need to measure the voltage *at* the fuel pump.

    Drop me an e-mail is you want to go through some things and figure it out...

    Squash
    <a target="_blank" href=http://www.trailrunners4x4.org/users/realsquash>http://www.trailrunners4x4.org/users/realsquash</a>
     
  4. Burt4x4

    Burt4x4 3/4 ton status

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    boy Dep I sure am glad I'm carberated.......[​IMG]


    Sorry couldn't stop myself....[​IMG]

    72K5[​IMG]Led Zeppelin[​IMG]Rock ON![​IMG]
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  5. Depdog

    Depdog 1/2 ton status Author

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    Ummm Burt, BITE ME :^)

    Realquash, its wired direct to the battery and I have even tried removing the relay and direct wiring it while cranking. No dice. Its the computer not telling the injectors to fire which in turn I think I have narrowed down to the trigger wire coming off the ignition

    Here are some details in case anybody else every builds the setup I have. I have the Crane HI-6 Ignition, it uses the stock magnetic pickup in the stock HEI distributer for its signal input, then it has a seperate green wire that is used for tach and or F.I. signal. It works my tach, but unless I have another vehicle jumping off mine, it wont work my f.i. on a REGULAR basis, every now and then it does and once it has been run, the residual fuel in the intake will let the engine fire off again and thats why it takes overnight for it not to crank. I recreated this by unhooking the fuel pump and cranking the engine till it would not fire. Hooked everything back up and wala, no cranking. Called Howell and they still say ignition, called Crane back and talked with a senior tech rep and he said I need one of their tach signal output boosters (or something like that) anyway, he GUARANTEED this to work. Said they had one other customer in Australia that had the same thing happen and this took care of the problem. So, in about 2 days I should have this 56 dollar wonder and see if it cures my problem. If it dont he is getting it back and I want my money refunded, he said that was fine but he KNEW this was going to work.

    GOD I hope he is right. I am way way tired of chasing this thing around and around in circles. Its driving me nuts!

    Depdog

    <font color=blue>Weenie K5, little mods' Small Tires!</font color=blue>

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  6. Shawn

    Shawn 1/2 ton status Premium Member Author

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    That sucks Glenn. I was VERY suprised mine fired up on the first start. This was the new engine being fired up for the first time also so I was a little nervous. It was running rough until I advanced the timing 10 degrees and has been running awesome since. I've done a little more tweaking on the timing and fuel map lately. How much did Howell charge for the whole setup? Did they burn your chip to match your cam/heads?

    Shawn
    87 K5
    few mods [​IMG]
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  7. Depdog

    Depdog 1/2 ton status Author

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    I got it from a fellow club member who had it on a 350 that was as close a match to mine as I could hope to find. Gave 300 bucks for the whole setup. He had the 350 built out the wazoo and the Howell did not produce enough fuel for it after that. He went to the multi port Edelbrock unit.

    Depdog

    <font color=blue>Weenie K5, little mods' Small Tires!</font color=blue>

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