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Thread: auto trans throttle spool

  1. #1
    Senior Member SBL's Avatar
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    auto trans throttle spool

    I am just checking on 2 things, as I am just now really getting to look around at my recent acquisition.

    1) For an auto trans, are there supposed to be 2 cables involved with the throttle spool? Mine does have 2, and I can't find documentation that it should.

    2) At one time I had a functioning "kickdown" at WOT. I seemed to have lost that. The WOT microswitch is working, based on reading the lambda duty cycle (dwell) going to 60 and steady when the switch is depressed. And, when the gas pedal is depressed, the microswitch is engaged. Is this the same switch that is responsible for kicking into 2nd gear on WOT? I cannot find the wiring that documents that, but I know its out there. How might I trouble shoot this?
    Steve Liggett
    Treasure Island, FL
    1982 automatic, VIN 10342, grey int

    Previous: VIN 5983, VIN 3670
    Who knows where my previous 1981 with 6 cylinder Chevy engine is these days (cannot find that VIN) ?

  2. #2
    Delorean Guru
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    There are 2 cables, one goes to the gas pedal and one goes to the shift computer aka governor. There are 2 WOT switches. one is for the Lambda system and the other is for the auto trans. The are mechanically tied together but are separate electrically. For more info refer to the section on automatic transmissions in the Workshop Manual. Since you just got the car you should drain and replace all of the fluids and filters. I also recommend doing all of the external On-Car service checks and adjustments for the auto trans. Make sure the wiring harness to the shift computer is secured and away from the hot exhaust pipes.
    David Teitelbaum

  3. #3
    Senior Member SBL's Avatar
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    There is not much on this in the Workshop Manual. I may have missed it, but I don't see any reference to that throttle cable line. The manual also just calls it a microswitch, without further explanation except how to position it. My switch has the metal plate, and 2 contacts. I had assumed that one contact was ground and the other the active line. Are they both active and the plate is ground, and thus 2 switching events are occurring?
    Steve Liggett
    Treasure Island, FL
    1982 automatic, VIN 10342, grey int

    Previous: VIN 5983, VIN 3670
    Who knows where my previous 1981 with 6 cylinder Chevy engine is these days (cannot find that VIN) ?

  4. #4
    Senior Member SBL's Avatar
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    I am going to look at it again in the light of day and check it with my meter. The 2 external metal tabs may have nothing to do with the switching, which I am now thinking is internal. Or, the PO may have installed an incorrect switch.
    Steve Liggett
    Treasure Island, FL
    1982 automatic, VIN 10342, grey int

    Previous: VIN 5983, VIN 3670
    Who knows where my previous 1981 with 6 cylinder Chevy engine is these days (cannot find that VIN) ?

  5. #5
    Administrator Ron's Avatar
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    Those are not contacts. They are buttons for the two micro switches. One is the "Full Throttle Enrichment Switch" (or "Full Throttle Switch"), which has a Light Green wire. The other is the, "Kick Down Micro Switch" (or "Kick Down Switch"), which has a Light Green w/Green Stripe wire. Both switches are normally open and supply ground when activated via the two black wires.

    Part 171 & 150 on schematic in Resource Section HERE.
    Cables and micro switch adjustment, WS Manual G:05:02.

  6. #6
    Senior Member
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    Further explanation of the two different wide open throttle microswitches for automatics here: http://dmctalk.org/showthread.php?13...l=1#post196505

    Subtle wire colour differences as Ron mentioned.

    More information and pictures of what that second throttle cable goes to here: http://dmctalk.org/showthread.php?10...l=1#post152180

    It basically goes to a piece of the transmission computer to help it figure out when to shift. You can see the two extremes shown in the photos, no gas and floored.


    Sept. 81, auto, black interior

  7. #7
    Senior Member SBL's Avatar
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    These last few replies were very helpful. I couldn't help but go to the garage and look. It seems that I do have the correct switches. I detect mechanical closure, and electrical closure at the connector. Since I had kickdown when I last drove it 2 days ago, I need to take a look at things closer in the daytime. Does the wire for this go through one of the bulkhead connectors? Thanks
    Steve Liggett
    Treasure Island, FL
    1982 automatic, VIN 10342, grey int

    Previous: VIN 5983, VIN 3670
    Who knows where my previous 1981 with 6 cylinder Chevy engine is these days (cannot find that VIN) ?

  8. #8
    Senior Member SBL's Avatar
    Join Date:  May 2011

    Location:  Treasure Island, FL

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    I cleaned all the connectors, and the switches where they meet the flap, and kick down now works. Here is what I hear and feel. The transmission goes into 3rd gear at 30 MPH. So at say, 40 MPH, I go to full throttle. I will jump to 2nd and I experience about 3-5 seconds of even more boost. I am thinking that is the enrichment, which must be timed or something, but you can feel it and hear a deep roar for that time. It remains in second until I go off of wide open. Does that sound about right?

    This careful observation, of course, led to another thing I am questioning. While I can clearly feel it shift from 2nd to 3rd, I cannot sense the transition from 1st to 2nd. I suppose that it may be starting in second? That may be like it is supposed to be. But, at say 10-15 MPH if I put the shift lever to 1st, shouldn't I feel that downshift?
    Steve Liggett
    Treasure Island, FL
    1982 automatic, VIN 10342, grey int

    Previous: VIN 5983, VIN 3670
    Who knows where my previous 1981 with 6 cylinder Chevy engine is these days (cannot find that VIN) ?

  9. #9
    Administrator Ron's Avatar
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    That sounds about right. See D:01:12 for the acceleration enrichment circuit.

    I forget at what MPH/RPM, but if the shifter is in 1st as you slow to a stop, you should feel the 2-1 downshift when it gets slow enough.

    It's easy to test- Pulling Fuse #10 will force the trans into 2nd. So, if pulling away from a stop is the same when Fuse 10 installed and when not installed, you have no 1st.
    If it is starting off in 2nd, you should stop driving it until you fix the problem because the clutches in a DeLorean will burn up quicker than most in this situation. A very common cause of failure.

    EDIT: Corrected Fuse "#10" to "#13"

  10. #10
    Delorean Guru
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    The shifts can be subtle so the best way to know what gear you are in is to hook up a light box and observe the lights to see what gear the shift computer is commanding the valve body to go into. Downshifts are dependent on throttle position, vehicle speed and engine speed and manifold vacuum so with all of those variables there is no way to check it except to see that it does downshift. You can also print out the chart of engine RPM's vs road speed to see what gear you are in. Upshifts are more defined than downshifts. The WOT Lambda switch is supposed to force the frequency valve into full duty cycle to give you some more fuel. The CPR also gets a vacuum spike and acts like an accelerator pump on a carb and gives a shot of fuel so it would be normal to notice a "boost" when you floor the accelerator pedal. Just don't expect much from the automatic, it is not a lot of HP and is not as torquey as the 5-speed. Puling fuse #10 removes power from the shift computer and the transmission will default to 3rd (lmp home mode) unless you have the shift selector in 2nd or 1st.
    David Teitelbaum

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