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Thread: M50 coils, main relay or fuel pump relay?

  1. #11
    Join Date
    Jan 2004
    Location
    Boston, Ma
    Posts
    441

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    It really shouldn't matter as everyone else has said, they won't ground out unless the are grounded through the ECU. Think about why I burnt mine. I didnt have the spark inverted so they were always grounded until they recieved the signal and turned them off, cause thats how traditional points work. The plugs fire when the points disconnect. It really isnt too much of a concern. I know that our coils are not powered through the fuel pump relay because the fuel pump relay turns off if the car doesnt start within a couple of seconds and the coils will continue to fire, i did some tests before i tore the OBD-1 off. My entire problem was due to mis configuration of megatune, not to wiring problems.

  2. #12
    Join Date
    May 2006
    Location
    Perth Western Australia
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    438

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    Quote Originally Posted by joshua43214
    As a follow up to Javier's post, I am 99% sure it is only rpm signal that is used to keep the fuel pump active. I think the only other criteria for fuel shut down is airbag deployment.
    Not trying to inflame but some models use the oil pressure switch signal to switch the fuel pump on after the starter is disengaged. In the event of a roll over or the lack of oil in the sump shuts the engine down (common on GM cars).

    FYI : The new BM models use the oil level sensor and will go into 1 of 3 limp home modes if he oil level drops to a predetermined level.
    In the event of an accident they have a pyrotechnic device that seperates the positive battery lead at the battery triggered after the front curtain airbags deploy.
    Last edited by Ausmpower; 05-31-2006 at 09:24 AM.
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  3. #13
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    Jan 2004
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    Boston, Ma
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    Im pretty sure that is a domestic only thing. I think GM does that on the older F-Body and maybe Vette. Not positive, but im pretty sure BMW never did that.

  4. #14
    Join Date
    Mar 2006
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    811

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    Quote Originally Posted by bjl4776
    Im pretty sure that is a domestic only thing. I think GM does that on the older F-Body and maybe Vette. Not positive, but im pretty sure BMW never did that.
    yep, and fords had the stupid switch that would pop when you hit a speed bump and make your care die infront of your kids school in front of all his friends, proving once again that parants are fools.

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