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Little FYI and a ?

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  • Little FYI and a ?

    I read a post here I thought about how to tell if your ecm/efi was running in open or closed loop. If you are running a gm efi setup and have a service engine soon light hooked up that you can ground the B terminal on the ALDL with engine running and the ecm will go into Field Service Mode. The ses or mil light will flash for
    OPEN LOOP flashes two and a half times per second and in
    CLOSED LOOP light will flash once per second.

    Another thing that will happen is the light will stay off most of the time in closed loop if the system is running lean and will be on most of the time if the system is running rich!

    This is straight out of a Gm service manual so blame gm if it does not work.

    Bill said to read up on the whole efi system before attempting the conversion so I have been freshing up since I have been out of school (trade school) a few years.

    Now for ? I had forgot about the EGR valve on a gm engine and since my 304 in the 800 has not one what will I do if everyone else that is running the conversion is using one on the IH motors. Do I need to scrounge up a later year model 304 intake with a EGR valve. If I need a new intake that will be a plus as I can get it all setup for the tbi while still driving my scout and then just install the other intake later.Thanks for any input.
    My "Disasterpiece"
    1970 800A 4X4,HFI'd,304,B/W,27,44,3:73,28's.
    The rest are in my 25 year plan!

    My "Ruedh"
    FREE 1972 1110 4x4,V8(?)727,205,44 drum/60/3.54's,small cheap tires.
    LOOOOADS-O-RUST!! Donor body located. Not!! JY owner played the "crusher value" card. : angry:
    NON-working rear window. Need info!!!

  • #2

    Good job on the studying......
    Did you read about the ALDL mode yet?
    I originally made an octopus on the end of my WINALDL cable so I could just jumper to each diagnostic mode without changing cables. but since I run my laptop each time I'm working on it, I just use it to tell me what I need to know.

    As for the EGR. I Run an egr on my street scout and I disable it on the trail scout When I burn the chip.
    Just let the person know who does your chip which way you want it.

    Bill USN-1

    May be the answer to all your fuel injection needs!
    Learn to do it right.