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Thread: 08 F-150 85lb/min air flow limit?

  1. #1
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    08 F-150 85lb/min air flow limit?

    Can anyone tell me if the 08 F-150 (Green Oak 1538K, I think) ECU has an airflow limit? I understand the voltage limit, but it seems that above 85 lb/min of air flow the airflow reading on the ECU drops out in the datalogs. The maf voltage is only ~ 4.75 V so I can only conclude there is also an airflow limit.
    Last edited by ElecTech; 05-04-2015 at 11:07 AM. Reason: wrong ECU type
    Jaime

  2. #2
    HPT Employee Eric@HPTuners's Avatar
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    Quote Originally Posted by ElecTech View Post
    Can anyone tell me if the 08 F-150 (Green Oak 1538K, I think) ECU has an airflow limit? I understand the voltage limit, but it seems that above 85 lb/min of air flow the airflow reading on the ECU drops out in the datalogs. The maf voltage is only ~ 4.75 V so I can only conclude there is also an airflow limit.
    There is no airflow limit via the MAF curve, but if other things in the tune are not raised up, the airflow can get clipped.

    Post the file, I'll take a look.
    Eric Brooks
    HP Tuners, LLC

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    I'll get it posted this afternoon for you. Thank you.
    Jaime

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    Eric,

    Here is the current calibration. I'm running Ford 60lb injectors so the MAF table and injector sizing has been scaled down a little to keep the reported airflow below 86 lb/min.

    So, what happens is, when the reported airflow value reaches 86 lb/min, the reported MAF value immediately drops to single digits, but the MAF volts continue to climb. The AF ratio drops in direct correlation to the MAF drop.

    P.S. we need the Stoich constant added to these definitions.


    Thank you.
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    Jaime