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Thread: $OD Switch from TBI to CPI - Corvair Pickup - Airflow Issue

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    Fuel Injected! corvairnut's Avatar
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    $OD Switch from TBI to CPI - Corvair Pickup - Airflow Issue

    I know my projects are a little out there with the Corvair, but everything we do is learning (for me anyway). Its all from scratch on this end since I have to run 2 throttle bodies. I have the dual TBIs running for years now with good results... so that means its time to switch. I bought a Corvair Pickup and wanted to EFI it with MPI instead of TBI. I want to stay with GM 16196395, but wanted to do something a little different.

    I used the mini injector from 03 Vortec, so I have 6 injectors directly above in intake runner of each cyl (3 on each bank). I switched to a CPI chip and everything runs pretty good, but I'm having a idle issue and I have narrowed the "symptom" to airflow.

    Quote from another thread:
    1project2many
    Airflow is calculated using MAP, RPM, displacement, volumetric efficiency, and air temperature. This calculation is the heart of speed density.

    When my engine is idling, the lowest idle is around 1200 unless I plug the IAC opening. Idle stops are already at bottom. the IAC count is around 20, when I change to "IAC counts vs Airflow" to 0 @ 43.8% airflow, then idle drops to 750 as it closes the IAC. Trouble is, no idle under load and of course and other issues I'm sure. So this is telling me that the calculated Airflow is way out of whack.

    Why is it calculating 40%-50% airflow at idle?

    What am I missing. I started with a BPLH CPI bin and started right away after my DIS adjustments. I adjusted the injector rate to make it drivable, but I am missing something simple Im sure.
    Last edited by corvairnut; 06-21-2015 at 09:35 PM.
    Ted Brown
    Anderson, SC
    68 Corvair EFI
    61 Corvair Loadside Pickup (Future EFI)

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