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Thread: Timing getting cut under load

  1. #1
    Tuner in Training
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    Timing getting cut under load

    This is a 403 afr 230 heads, fast 102, N/W102 T/B, 239/623/113 +2 cam, 04 gto ecm and harness, 4l60e.
    its tuned for mass air. month or so ago it started having lean spikes while driving. I couldn't figure it out but I did figure out if I unplugged the mass air it wouldn't lean out, so iv driven it like that the past few weeks. Then I started having problems with a major bogging issue. Ive scanned it and its pulling timing for some reason[only under a load]. If I rev it in park it rev's fine, but know I can foot brake it and its a constant bog timing sometimes going in the negative.
    Please help I have an event coming up and I'm lost. Fuel pressure isn't dropping. If U don't see any thing in tune please give suggestions as to what it may be.
    I can drive it lite on the gas and it drives fine.
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  2. #2
    Senior Tuner Russ K's Avatar
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    Go to torque management > general, and return the max torque fields to stock. If that fixes your issue, then you can zero the spark retard vs torque reduction.

    But this won't fix your lean condition at WOT. Your not logging rpm, but your pe table is 1.081 up to 2400 rpm. Is this a LS swap vehicle?

    Russ Kemp

  3. #3
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    Yes Sir, its a ls swap, I can try that tomorrow. Thanks
    O the lean condition isn't at WOT, Its at a cruise or lite acceleration.
    Last edited by randall; 10-18-2014 at 07:56 PM.

  4. #4
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    I see what Ur saying about PE but it doesn't kick in until 3000 rpm, car has a 3200 stall. Im open to better suggestions.

  5. #5
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    Here are a few more log files. One from 9/1/14, The other from 10/8/14. 9/1 was when it was having lean spikes with mass air hooked up. 10/8 is bog with mass unhooked. It didn't start the Bog instantly. It started occasionally and now is almost consistent and does it with mass air or not. Can anyone tell if the 02 sensors are going out? This is a swap vehicle but its not new. Its been swapped since approx. 09
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  6. #6
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    Quote Originally Posted by Russ K View Post
    Go to torque management > general, and return the max torque fields to stock. If that fixes your issue, then you can zero the spark retard vs torque reduction.

    But this won't fix your lean condition at WOT. Your not logging rpm, but your pe table is 1.081 up to 2400 rpm. Is this a LS swap vehicle?

    Russ Kemp
    Russ I don't have a file with stk. max torque fields, but I did zero out the spark retard vs torque reduction and no change. Im going to buy new 02 sensors and plugs today.

  7. #7
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    Finally figured it out. TCC Relay was stuck and didn't open when the brake was pushed some how causing ETC to cut timing. First I disabled ETC LIMITS and the bog stopped and then when driving I realized the converter was acting up. Then I remembered talking to James whom had mentioned the brake sw. because it was bogging if I brake torqued it. I didn't think much about it at first because it had never bogged on the line at the drag strip. So driving to work yesterday I realize the TCC relay and wiring could cause this so I checked and sure enough the relay wasn't opening