diablo tuner, truck dies

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by cory100fm, Jun 20, 2013.

  1. cory100fm

    cory100fm New Member

    OK, a buddy of mine has an 07 4.8L 2wd silverado and installer a Diablo tuner to compensate for a larger tire siz and yet correct speedo readings. He switched back to a factory size tire and tried to pull the settings with his Diablo tuner unsuccessfully. I work at a dealer and told him we could try reprogram his ecm to the latest update and that should get him back to factory specs. He didn't tell me he only used his tuner to change tire size or I would have changed that with a tech 2. I figured he did some kind of engine tune or something. Well after reprogramming the ecm the truck ran great until he drove 20 feet and it died. Idles fine but once you drive drive 15 to 20 feet it just dies. No codes stored any modules. I performed ck. Shaft variation relearn and idle relearn after programming. Anyone have a clue what I should do? Truck ran great before.it seems to idle a little lower now. Should I just try and adjust things with the Diablo?
  2. TimTom64b

    TimTom64b Epic Member 5+ Years 500 Posts ROTM Winner

    Which model do you have? I have the trinity and to role any changes off all I would do is select uninstall tuner... this resets the ecm and TCM back to before the initial install.

    You said you installed/updated the ecm? If you did this while the tuner is installed... I'm not certain but you may not be able to just uninstall the tuner now. I'd recommend calling their tech support.
  3. cory100fm

    cory100fm New Member

    I'm not sure which model he has, he forgot to bring it lol. He said he tried to uninstall but was unable to do so.
  4. j cat

    j cat Epic Member 5+ Years 1000 Posts

    since the PCM is now programed and you have no codes check the fuel rail pressure. low idle no codes can be fuel pressures too low.
  5. cory100fm

    cory100fm New Member

    I was planning on checking fuel pressure that day but a big storm was blowing in and I was on my bike that day, so I hauled ass outta there. Ill check it Monday.

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