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Thread: 98 7.4 vortec no start

  1. #1
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    98 7.4 vortec no start

    troubles again parked the rv a few weeks ago running perfect today will not fire at all tried some starting fluid in intake nothing engine turnes over good no fire on any cylinders and was runing perfect a few weeks ago ? all fuses good , ecm maybe ? are there any aftermarket ignitions that do not require a dealer to program the ecm , I am open for all ideas engine has only 32 k for millage

  2. #2
    Senior Moderator chevychase's Avatar
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    Check for spark at dist. cap no spark ..check at coil. Check for power at coil.
    No spark at coil probably the ignition control module ..can take it to auto parts for a test
    Would not think ecm . Do you have a service engine light? Would get a code for bad ecm.
    Here is a link that will help check things good for 7.0/454 also. just click on red link Part 1 -GM Misfire, No Spark/No Start Tests (4.3L, 5.0L, 5.7L).

    Gitter done have fun. Running on empty...running blind...running behind.....
    IF I CAN GET YOU TO SMILE BEFORE I LEAVE.

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    it is my understanding power to distritor is tru ecm and each cylinder has a coil , would the icm stop all spark ? no fire at plugs

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    I have a 99 vortec 7.4 in a truck it has a ignition module and 1 coil for all cyilinder

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    do not use starter fluid!....check around and see if a varmit has been chewing...put a scanner on it
    4 wheels move the body
    2 wheels move the soul
    B.W.A.I
    Snow is a lot like religion and a lot like sex....you never know when you are going to get it!....or how much you will get

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    Senior Moderator chevychase's Avatar
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    Quote Originally Posted by bigred truck View Post
    I have a 99 vortec 7.4 in a truck it has a ignition module and 1 coil for all cyilinder
    Yuup a coil pack ..module on these beside the dist. on outside .

    Gitter done have fun. Running on empty...running blind...running behind.....
    IF I CAN GET YOU TO SMILE BEFORE I LEAVE.

  7. #7
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    Quote Originally Posted by chevychase View Post
    Yuup a coil pack ..module on these beside the dist. on outside .
    no he actually has a coil for each cyl mounted above the spark plug on the rocker cover with a 12' wire to the plug...in 98 is when gm made a special build and started using it in the rv chasiss
    depending on the build date there was a recall on the the resister for the air intake and an ecm reprogram
    4 wheels move the body
    2 wheels move the soul
    B.W.A.I
    Snow is a lot like religion and a lot like sex....you never know when you are going to get it!....or how much you will get

  8. #8
    Senior Moderator chevychase's Avatar
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    Icm would kill all spark...So will the crank sensor ..need to test all .

    Gitter done have fun. Running on empty...running blind...running behind.....
    IF I CAN GET YOU TO SMILE BEFORE I LEAVE.

  9. #9
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    lastest the engine does have one coil pak , I replaced the icm and still no spark leaving coil I guess the next step is I will change coil pak and the crank sensor and hope one of them works anything hopefully to avoid a tow to the dealership and their 169 per hour labor I relly am surprised there seems to be no aftermarket alternitives , I cut my teeth on carbs and mallory distri

  10. #10
    Senior Moderator chevychase's Avatar
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    Do you have a service light light? Usually this is usually .a coil pack will go bad on 1 or 2 cylinders not all. but.
    Most times will get a light on crank sensor . here is a link to check out http://www.easyautodiagnostics.com/c..._sensors_1.php
    Last edited by chevychase; 08-08-2012 at 04:43 PM.

    Gitter done have fun. Running on empty...running blind...running behind.....
    IF I CAN GET YOU TO SMILE BEFORE I LEAVE.

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