idle jumping after maintenance

Discussion in '80-Series Tech' started by Vertigo44, May 4, 2017.

  1. Vertigo44

    Vertigo44

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    Overdue for state inspection and was getting P0401 EGR insuf..

    Pulled the 3 throttle body cables by only turning the nuts just enough to be able to slip them off the bracket.
    Pulled the upper intake manifold
    Replaced the VSV solenoid
    Replaced the EGR actuator/solenoid (blue)
    Replaced the valvecover gasket / plug gromets / cleaned
    Cleaned the upper intake egr port / EGT sensor / intake etc
    Replaced all hose with silicon vacuum hose
    Replaced the IAC solenoid on the TB
    Reinstalled everything

    Now upon starting the truck idled around 2k for about 3-4 mins and slowly started stepping down the rpms until all of a sudden the rpms started jumping around from 2k to 3k and back and forth very frequently. Initial codes were reporting just about everything (iac, map, thottle, egr) cleared. restarted with the same results. Scanned no codes but I think that just b/c i scanned too soon and didn't try and drive it that way. Thinking it maybe throttle cables but not too sure. Thanks!
     
  2. flintknapper

    flintknapper

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    Checked your TPS?
     
  3. Mighty690

    Mighty690

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    When you pull the battery cables the computer needs to recalibrate. It takes a few restarts. Mine is idling low since I pulled the battery. In another day or two the engine will be idling as usual on startup.
     
    DirtScaresMe likes this.
  4. DirtScaresMe

    DirtScaresMe Trouble Maker SILVER Star

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    I'd rule out the ECM recalibrating which happens everytime the battery is disconnected. Takes a few trips to resolve.
     
  5. Vertigo44

    Vertigo44

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    Yup hear you on the relearn process but i never disconnected the battery.
     
  6. Vertigo44

    Vertigo44

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    It was late a night and dark so hopefully it's something simple like a vacuum hose i missed. Ill keep you posted. Thanks!
     
  7. DirtScaresMe

    DirtScaresMe Trouble Maker SILVER Star

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    What silicone vacuum hose did you use, just curious?
     
  8. Vertigo44

    Vertigo44

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    Well well. Where to start.

    Truck is running better than the day I bought it with 220k miles on it

    The ebay IAC I bought came with a plastic plunger that broke off and on top of that the plunger coming out of the IAC was too narrow compared to the okd unit.

    Skipped the basics and forgot to compare new to old parts prior to install. Its never idled so smooth!

    Thanks guys!
     
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