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Last Suburban/Blazers made without a computer

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by stu454, Dec 29, 2003.

  1. stu454

    stu454 1/2 ton status

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    I was curious when the last vehicles were made without a computer of some sort that would manage the engine/tranny/etc.

    Thanks,
     
  2. ankarback

    ankarback 1/2 ton status

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    If I´m not mistaken the last year was 1986. In 1987 they got EFI. The diesels could be without a computer a bit longer but I´m not sure about that.
     
  3. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    My 83 Blazer did not come with a computer , although there is a blank spot on the fuse box that says ECM. I think until fuel injection, some were computer carbs in california for sure, but not neccesarily everywhere else. /forums/images/graemlins/k5.gif
     
  4. HarryH3

    HarryH3 1 ton status Author

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    '87 was the first year for total engine management by computer. But several years before that they had computer controlled metering rods in carbs and electronic spark timing controls. So one could argue that those were "computer controlled" to some degree.
     
  5. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    [ QUOTE ]
    '87 was the first year for total engine management by computer. But several years before that they had computer controlled metering rods in carbs and electronic spark timing controls. So one could argue that those were "computer controlled" to some degree.

    [/ QUOTE ]

    Bingo
    85 had iut but no computer control on the carb. the solonoide was controled y a simple temp sender.did have a ECM for the ESC . I think 84 was first year for that set up.

    Stu......I don't smog my 88 Burb in Cobb

    8600lb GVWR on the 3/4's make them exempt.
     
  6. beater_k20

    beater_k20 Banned

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    i've seen ESC models as early as 1982. and as for the last year without a computer, 1986. even the ESC trucks did not have a computer. they had a control module under the dash, but no computer.
     
  7. R72K5

    R72K5 Banned

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    1979 was last before engine spark timing control module which is a small ECM

    most all 1980-up 1/2 tons and cars all had this, ppl dont tend to remember it existed though, its the EST system, and also ESC was before TBI years too, and then dont forget about early 80s CFI system
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

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    [ QUOTE ]
    as for the last year without a computer, 1986.

    [/ QUOTE ]

    That isn't correct as was stated earlier. '85 was AT LEAST the earliest year for the CCC system on some trucks, but my parts manual only goes back that far. It would be *possible* although not probable, that the system could have been used since 1981, as that was when it was required on all carbureted GM *cars*.

    As to CCC (whether car or truck, only difference appears to be knock sensor in some applications and not others) not using a computer, it uses an ECM with a PROM, (extremely slow by later year standards of course) what else is it if not a computer?

    Re-reading THIS post of mine, I didn't make it clear that there is a huge variation in which trucks got what, between the different GVW trucks, and the end destination. CA trucks, as can be expected, are the only ones I have found, that had CCC systems on them. (even then, GVW was an issue that determined CCC or not) Everything Federal stayed "standard" (no ECM control of the engine) until 1987 with TBI. The ESC uses a module, not an ECM, so don't confuse the two. IMO ESC was brought out to run the 9.2:1 compression (with crappy heads) in the truck 305's, without having warranty issues, and without the expense of CCC. (again, $$$ in GM's pocket)
     
  9. stu454

    stu454 1/2 ton status

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    Thanks y'all!

    Happy New Year!
     
  10. Steve_87K5

    Steve_87K5 1/2 ton status

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    My '85 K5 5.7 had a computer. California emissions pkg. It had a Quadrajet with several wires coming out of it (type E4MD IIRC). Main metering was not controlled; idle mix was PWM, and I think there was some kind of a fuel bowl level control also. Carb made a ticking sound at idle.

    As for ESC, this used a module mounted on the intake, and did not involve a microprocessor AFAIK. You could watch the timing retard on scope by tapping the block with a small hammer.
     
  11. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    [ QUOTE ]
    My '85 K5 5.7 had a computer. California emissions pkg. It had a Quadrajet with several wires coming out of it (type E4MD IIRC). Main metering was not controlled; idle mix was PWM, and I think there was some kind of a fuel bowl level control also. Carb made a ticking sound at idle.



    [/ QUOTE ]I had the exact same setup as you.

    [ QUOTE ]
    As for ESC, this used a module mounted on the intake, and did not involve a microprocessor AFAIK. You could watch the timing retard on scope by tapping the block with a small hammer.

    [/ QUOTE ] I don't know if that is what I had???? I had a computer or ECM or whatever the f&$k the thing is behind the glove box.
     
  12. dyeager535

    dyeager535 1 ton status Premium Member

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    Standalone ESC is smaller than an ECM. Look similar, metal box, but once you've seen a GM ECM and ESC, you can tell the difference easily. ECM size was constant at least from 1981-1991, probably longer.
     
  13. bryguy00b

    bryguy00b 3/4 ton status

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    [ QUOTE ]
    I had a computer or ECM or whatever the f&$k the thing is behind the glove box.

    [/ QUOTE ]

    are u talking about that round silver thingmabob mounted on the pass. side air vent on the kick panal?..what is that thing...my 84 k5 has one..
     
  14. dyeager535

    dyeager535 1 ton status Premium Member

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    I believe you are talking about the vent diaphram for an AC rig.

    ECM or ESC modules are mounted "behind" and "above" the glovebox, although some of the first ESC ones may have been above the gas pedal IIRC.
     
  15. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    [ QUOTE ]
    [ QUOTE ]
    I had a computer or ECM or whatever the f&$k the thing is behind the glove box.

    [/ QUOTE ]

    are u talking about that round silver thingmabob mounted on the pass. side air vent on the kick panal?..what is that thing...my 84 k5 has one..

    [/ QUOTE ]no
     
  16. txbartman

    txbartman 1/2 ton status

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    [ QUOTE ]
    As for ESC, this used a module mounted on the intake, and did not involve a microprocessor AFAIK. You could watch the timing retard on scope by tapping the block with a small hammer.

    [/ QUOTE ]

    As Dorian said, the ESC was a essentially a PROM. It is mounted inside the cab behind the glove box. It has a sensor feed from a knock sensor screwed into the block. It outputs wires and a plug to the factory HEI distributor.

    The reason you could see the change when hitting the block is that the knock sensor would pick it up, transfer the info to the ESC module, and it would retard the distributor.

    However, for all intesnive purposes, this is NOT a computer on the motor. Key is, up until 1987 (TBI) on non-Cali rigs, there is no computer or electronics controlling engine functions that can't be EASILY removed withtout any noticeable impact on the engine's performance.

    Is that what you needed to know?
     
  17. Steve_87K5

    Steve_87K5 1/2 ton status

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    The knock sensor (sometimes mounted into one of the engineblock water drains) is basically a piezioelectric transducer, or type of microphone. The wire from the knock sensor (at least on the K5 which I worked on, an '81) appeared to plug into a small module, mounted on an intake manifold bracket. I thought at the time, that this module was probably a preamp and schmitt trigger ckt. I was unaware that there was another ESC-associated module in the cab. (did this waaaaay back in 1988)
     
  18. Steve_87K5

    Steve_87K5 1/2 ton status

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    E4MED is the California Computer Controlled Carb (CCC) which was on my '85. I left out the "E" There is no E4MD, (thanks to Dorian for noting this)
     

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