Discussion in 'The Garage' started by larsfrog, Jul 21, 2004.

  1. larsfrog

    larsfrog Registered Member

    Jun 24, 2004
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    California, San Diego
    Correct me if I am wrong concerning the EGR valve ('86 305 non-ECM). When checking if the EGR valve is fully operational I was told to apply vacuum to the EGR valve (~5 in Hg) and hold up a rag to my exhaust pipes. After this if my engine stumbles my EGR is fully functional, if it does not stumble my EGR needs to be replaced because the pintle is not opening. Why would the engine stumble if my EGR is fully functional, and not stumble if it was not functional? I do not understand the dynamics of this, if anyone does can you please explain it to me.
  2. dyeager535

    dyeager535 1 ton status Premium Member

    Dec 13, 2000
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    Roy WA
    I don't see the point of the rag, but ok. /forums/images/graemlins/smile.gif

    I fyou push up on the bottom of the EGR valve while the engine is running, it should stumble, and most likely die.

    If the passageways are clogged up, or you can't move the valve, then it won't introduce the exhaust gas into the intake, and the engine won't stumble.

    Don't know if you are familiar with EGR operation, but it is introduced after the carb (or TB in all cases) so it is not "measured" by whatever you deliver air and/or air/fuel with...the carb etc., can't compensate for the EGR at idle, as it was never designed to handle the exhaust gas at that engine load and RPM. EGR is only designed for cruise, so if it is introduced any other time, performance suffers.

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