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Thread: Throttle and A/F surge on procharged

  1. #1
    Tuner in Training
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    Throttle and A/F surge on procharged

    Have a 2005 Dodge Magnum R/T with ported heads, longtubes, 85mm TB, a custom ground cam and a torqstorm procharger. When you first crank it over, the RPMs surge up and down for about 10-20 seconds before finding a smooth idle in P, but also at cruise speeds and light throttle around town, low in the RPM band, say around 1300-1700 there's a noticeable light "surging" in the rpms and you can watch the wideband keep running from about 15.2 - 13.5 just kind of shuttling back and forth. The tune was done by email, but I'm getting into tweaking it with HPtuners, I apologize if there's a lack of information, this is a first post. I tried searching the forums for a while and couldn't quite find a dodge with the same problem. Thanks for any guidance.
    Last edited by TerrysTrans; 05-18-2020 at 10:53 AM.

  2. #2
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    Can you post your current tune, current data log and what are the specs of the cam?

  3. #3
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    I'll try to pull a datalog a little later today, cam specs are
    installed @110 centerline
    Intake Exhaust
    gross valve lift .524 .524
    duration@ .006 268 276
    duration@ .050 214 222
    lobe lift .3180 .3180
    lobe seperation 117.0


    Tune file:
    thundergun modTBInManTMFSO.hpt
    Last edited by TerrysTrans; 05-18-2020 at 03:38 PM.

  4. #4
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    didn't get a chance to datalog (left the mpvi2 at the shop) but just some other possibly relevant info, running srt4 stage 1 injectors, ported intake manifold, high flow rails, stage one colder plugs, and the a/f ratio shuttle seems to happen at under 20% throttle.

  5. #5
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    very short logs, if you need more information or PIDs, let me know, again, I apologize, first post. Thanks for any help. One of the startup self-revving, one of light throttle cruise shuttling. Wideband goes 15.0-13.5 when it shuttles around.

    shortcruisethrshuttle.hpl
    warmstartup.hpl

  6. #6
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    bump

  7. #7
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    tgWOTrun.hpl

    short WOT pull. WBO2 reads around 12.8

  8. #8
    Tuner in Training
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    Had the same issue, start by reducing airflow from <= .71V by 10% and see if that helps. Keep reducing by 10% until surging is gone.

  9. #9
    Tuner in Training
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    Matching the ETC tables (altered for bigger TB) to the small range and large range tables seems to have helped.