Rebuilt CCC Qjet Tuning

Discussion in 'Engine Topic' started by MP81, Oct 8, 2019.

  1. MP81

    MP81 Veteran Member

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    Perfect, thanks - I can honestly say I've never seen that sensor on the car before - but looking at a picture I have of my engine bay, it sure looks like it is there!

    Looking on RockAuto, that would be the two-wire ones they list?
    [​IMG]

    Looks like this would be a good spot to tee for this sensor along with my DD gauge sensor if I replace it, so I'm not only getting a coolant reading when the thermostat opens.
     
  2. RickM

    RickM Veteran Member

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    If your wiring is all original that sensor wont work unless you get an adapter. The original has a "button" type connector.
    The sensor will look like this:
    [​IMG]

    Do not hook this up to your gauges, it will not work. It's purpose is to tell the ecm when the engine is up to temp.

    The values (Ohms) that is sends to the ECM likely will not be the same as your temp gauge sender that is used to drive the temp gauge.
     
  3. MP81

    MP81 Veteran Member

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    Yeah, my DD sender is its own thing, it is currently separate and would stay that way.

    Okay, I'll poke my head in the engine bay and have a look for this thing.
     
  4. 1980RS

    1980RS Veteran Member

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    CTS sensor need to be in the intake manifold some place otherwise you will get a false reading.
     
  5. MP81

    MP81 Veteran Member

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    I never moved it, so I expect it to be there.

    The pic I looked at earlier, while at work, looked to show it where it should be.

    Somehow it's something I've never picked up on being there, despite having been in the engine bay for what seems like an eternity now.
     
  6. MP81

    MP81 Veteran Member

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    All right, found the sensor. Wires definitely look a bit sketchy, but I don't expect they looked any different than this before. Anyway, I pulled them apart a bit so they're at least not so near each other.

    IMG_20191011_164801866.jpg IMG_20191011_164809071.jpg IMG_20191011_164954175.jpg

    Started the car up and let it run up to temp, but I still only get a dwell reading of 3. I mean, maybe I am doing something wrong here, or that diagnostic wire in the back somehow isn't hooked up? Rich or lean or perfect, it should still give me something other than 3, especially given that is what it gave me when it was running WAY rich the first install before I corrected the float.
     
  7. MP81

    MP81 Veteran Member

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    Hmm...looking at it now, that sensor doesn't seem to match...anything...
     
  8. MP81

    MP81 Veteran Member

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    Looks like I kinda stalled on this one a bit - haven't had much time this week to really get out there and mess with it.

    I was looking at the wiring diagram (http://nastyz28.com/camaro/wire/81w-ecm.jpg) and it seems like the diagnostic wire is the "same" as one of the MCS connector wires? Is that a wire that can be probed to see if maybe there's something up with the diagnostic wire? I feel like I should get some different number other than just "3", even if both the coolant sender and O2 need to be replaced?

    On that topic, the coolant temp sensor, with two wires, does appear to match what AutoZone shows in their topic on the CCC (https://www.autozone.com/repairguid...mmand-Control-CCC-System/_/P-0900c1528007dbb4), but does not seem to be anywhere online.
    [​IMG]

    I need to pull the connector off and see what it looks like underneath, but that does appear to all be factory...
     
  9. ale81

    ale81 New Member

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    FWIW, I had the same temp sensor wiring issue on my 81 (it appears that this was a common problem after doing some reading) and I gave up on finding the correct replacement pigtail connector. There are plenty of ones that will fit but they only have 1 wire and don’t have the center ring connection. I wound up putting in the later style sensor like the pic in your earlier post (along with the newer style pigtail) and it works great. I’m interested in how this plays out because I’m also fiddling with the CCC on my 81.
     
  10. ale81

    ale81 New Member

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    Do you hear your MCS clicking? If not, there may be other issues at hand. Sounds like your ECM is alive and you have a working O2 sensor (can be checked with a multimeter to be certain). Are you running the OE style distributor with the 4 pin connector? A previous owner had installed a “normal” older style HEI distributor in mine and I had to put in an OE style style with the EST connector to get my MCS to work. I think the computer needs the distributor pulse signal in order to send the MCS pulse.
     

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