Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Unknown Engine Sensor!!!!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Ditchdigger, Jun 8, 2003.

  1. Ditchdigger

    Ditchdigger Registered Member

    Joined:
    Mar 11, 2001
    Posts:
    96
    Likes Received:
    0
    Location:
    The Great Midwest
    Hi,
    I'm swappin sensors to another motor, and I am wandering about this one sensor and for the life of me can't remember what its for.

    Its located on passenger side of block on bottom in about the middle, and its a one wire hookup, you could say its just above the pan in middle of block, I have all other sensors accounted for water Temp on head/ Oil light switch by oil filter on block/ Oil pressure by oil filter on block,

    My other engine I'm swappin in has simply a plug in the hole, Nonetheless I will hook it up, just can't jog my memory. /forums/images/graemlins/thinking.gif
     
  2. Bubba Ray Boudreaux

    Bubba Ray Boudreaux 1 ton status

    Joined:
    Jan 21, 2001
    Posts:
    20,716
    Likes Received:
    2
    Location:
    Undisclosed Location
    Knock sensor?????????
     
  3. HarryH3

    HarryH3 1 ton status Author

    Joined:
    May 31, 2000
    Posts:
    10,384
    Likes Received:
    2
    Location:
    Georgetown, TX
    Bzzzt! We have a winner! /forums/images/graemlins/cool.gif It is indeed the knock sensor. It screws into the hole where the coolant drain plug would normally be located. Just unscrew the drain plug from the 'new' block and screw the knock sensor into the hole. /forums/images/graemlins/thumb.gif
     
  4. Ditchdigger

    Ditchdigger Registered Member

    Joined:
    Mar 11, 2001
    Posts:
    96
    Likes Received:
    0
    Location:
    The Great Midwest
    Jeez, I didn't think they had em in 84s,

    So, if it senses a knock it'll retard the timing at HEI dist. Why would it be needed if your timing is right on is it needed for different gas?

    Will it even work right if I'm going from a 305ci to a 454ci
    and I'm using the original HEI distributor from the 305?
     
  5. HarryH3

    HarryH3 1 ton status Author

    Joined:
    May 31, 2000
    Posts:
    10,384
    Likes Received:
    2
    Location:
    Georgetown, TX
    An '84 didn't really have an ECM, but it most likely had ESC (Electronic Spark Control) which would back off the timing when it detected detonation. /forums/images/graemlins/cool.gif
     
  6. R72K5

    R72K5 Banned

    Joined:
    Mar 5, 2001
    Posts:
    8,905
    Likes Received:
    0
    Location:
    central IL
    80 was first year for knock sensor and EST engine control system on trucks, 80 was first year of the new block castings, pass side oil stiock, new oil pan, etc., the ECM is smaller and under center area of dash standing up in brackets near column
     
  7. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,979
    Likes Received:
    189
    Location:
    Roy WA
    [ QUOTE ]
    Will it even work right if I'm going from a 305ci to a 454ci
    and I'm using the original HEI distributor from the 305?

    [/ QUOTE ]

    No. (speaking for injected setups, but I'd suspect earlier was the same way) Knock sensors are "tuned" to the engine they are attached to. Even a 305 and 350 use different knock sensors.
     
  8. Ditchdigger

    Ditchdigger Registered Member

    Joined:
    Mar 11, 2001
    Posts:
    96
    Likes Received:
    0
    Location:
    The Great Midwest
    hmm, well assuming it may not work right with the engine swap, would it bother anything to just leave it off or diconnected, and as far as distributor working correctly, or should I just hook it up.

    I'm leaning towards leaving it off, I keep my engines pretty well timed anyhow.

    To hook or not to hook, that is the question!!!
     
  9. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,979
    Likes Received:
    189
    Location:
    Roy WA
    There have been posts on here about how to "convert" an ESC distributor to non-ESC. With that said, not sure if you can just disconnect it and have it work right. I'd kind of think no, but maybe someone else can comment.

    I really haven't studied the intricacies of the truck ESC system, but it seems to have its fair share of problems. Who knows if thats owner related or system, but ESC on CCC and injected vehicles causes no more problems than anything else electrical.
     

Share This Page