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Thread: Dwell at 60 all the time

  1. #21
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    More info on those WOT (wide open throttle, or full throttle) microswitches here: http://dmctalk.org/showthread.php?13...-s-this-switch

    You mentioned having an automatic. You will have two of those WOT microswitches. One is for fuel enrichment and the other is for kicking down the auto trans into passing gear when you hammer the gas. Both of those switches plug into a Tetris puzzle looking connector and both can be plugged into either switch. While the switch itself doesn't matter (flap or no flap, they both activate at the same time), the pair of wires on the car side coming from those connectors does matter. Confirm both pairs are fine and not shorted or mixed up. The wire pairs look very similar, especially 38 years later with a lot of fading and engine filth, but one of them is 'light' green and the other is just green.


    Sept. 81, auto, black interior

  2. #22
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    Quote Originally Posted by Jonathan View Post
    More info on those WOT (wide open throttle, or full throttle) microswitches here: http://dmctalk.org/showthread.php?13...-s-this-switch

    You mentioned having an automatic. You will have two of those WOT microswitches. One is for fuel enrichment and the other is for kicking down the auto trans into passing gear when you hammer the gas. Both of those switches plug into a Tetris puzzle looking connector and both can be plugged into either switch. While the switch itself doesn't matter (flap or no flap, they both activate at the same time), the pair of wires on the car side coming from those connectors does matter. Confirm both pairs are fine and not shorted or mixed up. The wire pairs look very similar, especially 38 years later with a lot of fading and engine filth, but one of them is 'light' green and the other is just green.
    The WOT connector was disconnected several weeks ago but I’ll double check the wiring.

  3. #23
    Administrator Ron's Avatar
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    +1 Luke

    =====

    $.02

    For the early harness (and others iirc):
    The Throttle Enrichment Switch has a Light Green wire (LG).
    The Full Throttle Switch (WOT) has a Light Green with a Green Stripe wire (LGG).
    Both have a Black wire. If they are correct the others don't really matter (the switches make/break ground together).

    Disconnect the LG wire at Pin #7 of Lambda Control Unit to eliminate the 2 micro switches, the Thermal Throttle Enrichment Switch (in the VOD, Y-Pipe), and their wiring as being the cause of over enrichment.

  4. #24
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    Quote Originally Posted by Ron View Post
    +1 Luke

    =====

    $.02

    For the early harness (and others iirc):
    The Throttle Enrichment Switch has a Light Green wire (LG).
    The Full Throttle Switch (WOT) has a Light Green with a Green Stripe wire (LGG).
    Both have a Black wire. If they are correct the others don't really matter (the switches make/break ground together).

    Disconnect the LG wire at Pin #7 of Lambda Control Unit to eliminate the 2 micro switches, the Thermal Throttle Enrichment Switch (in the VOD, Y-Pipe), and their wiring as being the cause of over enrichment.
    I will try that tomorrow, thank you

  5. #25
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    Quote Originally Posted by Ron View Post
    +1 Luke

    =====

    $.02

    For the early harness (and others iirc):
    The Throttle Enrichment Switch has a Light Green wire (LG).
    The Full Throttle Switch (WOT) has a Light Green with a Green Stripe wire (LGG).
    Both have a Black wire. If they are correct the others don't really matter (the switches make/break ground together).

    Disconnect the LG wire at Pin #7 of Lambda Control Unit to eliminate the 2 micro switches, the Thermal Throttle Enrichment Switch (in the VOD, Y-Pipe), and their wiring as being the cause of over enrichment.
    Wow that's great info...I have the two plugs, but only one used (in a manual car). I'll have a closer look as I never noticed the different colors.

    At least in a manual car, the correct plugs seem to matter. I have done some continuity testing, and found that the throttle enrichment switch plug is normally open, and grounded when the microswitch closes. However, my unused kickdown switch has continuity, even though it's left dangling in the engine bay?!

  6. #26
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    Is this my diagnostic plug? If so, what’s the purpose of the jumper wire?59721D58-3A7C-4195-AE51-FD1E2DF3F4B4.jpg

  7. #27
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    More tests

    Disconnected light green wire from Lambda ECU. Disconnected O2 sensor per Lambda System Operation Check guide.

    Cold engine, OAT 75F

    Frequency valve dwell (4cyl scale) on startup: 45.5 and pretty steady

    Grounded O2 sensor wire to ECU: dwell steady at 85 (should be 87 per manual)

    Applied 1.5 volts to O2 wire to ECU: dwell jumps to 85 (should be maximum of 20 per manual)

    Disconnect 1.5 volts: dwell returns to 45 and steady

    Thoughts?

  8. #28
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    I should clarify that the dwell I was testing at the beginning of this thread was distributor dwell. That holds steady at 60. This recent test is frequency valve dwell.

  9. #29
    Senior Member Bitsyncmaster's Avatar
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    Quote Originally Posted by CFI View Post
    Disconnected light green wire from Lambda ECU. Disconnected O2 sensor per Lambda System Operation Check guide.

    Cold engine, OAT 75F

    Frequency valve dwell (4cyl scale) on startup: 45.5 and pretty steady

    Grounded O2 sensor wire to ECU: dwell steady at 85 (should be 87 per manual)

    Applied 1.5 volts to O2 wire to ECU: dwell jumps to 85 (should be maximum of 20 per manual)

    Disconnect 1.5 volts: dwell returns to 45 and steady

    Thoughts?
    I think your lambda ECU is bad. From you past posts, it seems like something is pulling up the O2 input to the lambda. I have some extra lambda ECUs but it takes a medium flat rate box to ship it.
    Dave M vin 03572
    http://dm-eng.weebly.com/

  10. #30
    '82 T3 FABombjoy's Avatar
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    Quote Originally Posted by CFI View Post
    he dwell I was testing at the beginning of this thread was distributor dwell.
    https://www.youtube.com/watch?v=2sF4MU1txTY

    You were measuring distributor dwell but talking about the O2 sensor & Lambda system? Those are completely disparate systems.
    Luke S :: 10270 :: 82 Grey 5-Speed :: Single Watercooled T3 .60/.48 :: Borla Exhaust :: MSD Ignition :: MS3X Fully SFI Odd-fire EFI :: DevilsOwn Methanol Injection

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