Conversions & Swaps LSX Engines in Non-LSX Vehicles
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Old Aug 21, 2016 | 03:42 PM
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Rick Hilfiker's Avatar
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Default LS3 Issues

I'm new to your forum but have always found the information helpful. My problem is with an LS3 crate motor that I have. First time startup went well and performance was great except when dropping the throttle quickly from the lower midrange position. It would go to the limp mode and reset itself after turning off ignition for a couple of minutes. I have since then updated the ECM to a later version (2010 Camaro) but to no avail. It sends code P0122 and P0222 (throttle position voltage). I have 5 volts at the accelerator pedal and the throttle body so I replaced the throttle body with a new one but to no avail. Have checked all the "new" wiring connections and find no problems. Grounds are good. The throttle plate does not move when pushing the accelerator with ignition on and now the engine only limps with help from starter. The ECM works well when put into another vehicle. Any help would obviously be greatly appreciated.
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Old Aug 21, 2016 | 04:01 PM
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From: Little Austin
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What harness and ECU do you have? If the ECU works fine in another vehicle, then clearly it is not the problem. I would focus your attention to the wiring and the throttle pedal. What pedal are you using?

Andrew
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Old Aug 21, 2016 | 05:26 PM
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I'm using a #25835421 Pedal Position Sensor, a #12633238 AC Delco ECU and a harness supplied by Howell. This combination worked fine for the first 3-4 hours with the exception of the quick throttle cutout.
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Old Aug 21, 2016 | 07:04 PM
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From: Little Austin
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Originally Posted by Rick Hilfiker
I'm using a #25835421 Pedal Position Sensor, a #12633238 AC Delco ECU and a harness supplied by Howell. This combination worked fine for the first 3-4 hours with the exception of the quick throttle cutout.
I'd double check the wiring...the pedal could also be bad....

Andrew
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