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Thread: ON3 N/A camshaft help

  1. #1
    Potential Tuner
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    ON3 N/A camshaft help

    Has anyone tuned a gen 4 5.3 with a ON3 N/A camshaft? I am having a hardtime keeping it running.2011 GMC SIERRA BASE TUNE3.hpt that is what I have so far. I had an oil starvation problem, and I would like to keep the truck running for more than 5 seconds or so to see if I am in need of new lower end bearings or what. PLEASE HELP.

    236/238 Duration
    .60x/.60x lift
    LSA- 113+2
    Assuming 1.7 Factory Rocker Ratio cam specs
    Last edited by bobdaugaard; 1 Week Ago at 01:15 PM. Reason: MORE INFO

  2. #2
    Senior Tuner
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    You should post your tune and log.

    That cam is a poor choice for this truck. by that I mean it's going to neuter power where a truck like that is driven most.. all for gains above 4800 RPM or so.
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  4. #4
    Senior Tuner
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    “and log.”

  5. #5
    Senior Tuner
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    Idle>RPM?Minimum Setpoint>VSS. You added 200 rpm to all the other idle tables but missed that one. I'm not saying that will keep it running because I've never not added to that table when adding to the others. But it is something to try. It also looks like no other tuning was done other than adding to the idle rpm tables and base running airflow. You seemed to have added enough to the idle airflow to keep it running but I saw no other tuning other than adding 2 degrees to the base idle timing where it would idle. That is a "too big cam" for a 5.3L in a heavy truck IMO also. But it should idle for more than 5 seconds with the changes you have made. I might suspect some kind of mechanical problem if it won't. You could try adding more to the start up airflow and the startup time underspeed just to keep it running. Also will it stay running with manual throttle (gas pedal) input?