RPMs drop when accelerating

Discussion in '7th Gen Dodge Charger' started by freakzilla, Oct 16, 2016.

  1. freakzilla

    freakzilla Member Photo Winner!

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    Hi Folks!


    Got a little problem (well, rather an annoying behavior of the car) - the dealerships near me seem to be overchallenged with problems that do not throw any codes.
    My V6 sometimes has a drop in RPMs when accelerating.

    If you start from a stand it´s almost not noticeable.

    As soon as you have to brake/ slow down under a certain RPM and then accelerate again the speed falls briefly during the acceleration process:
    With little throttle, when you reach about 2200rpm it drops down to aprox. 1800 and then raises again.
    If you accelerate faster, you notice it a little later - at about 3000 to 2600 and then further accelerating.
    At full throttle i don´t feel any drop at all.

    Always reproducable - regardless of whether automatic or Autostick, no matter what gear!

    I´ve resetted all adaptives (PCM/TCM) but that didn´t solve the problem...

    Had the car at 2 dealerships, but all they did was scanning the vehicle and no codes were thrown.
    So they refused to do anything :(

    Anybody got an idea or has had a similar problem?


    Thanks
    Alex
     
  2. freakzilla

    freakzilla Member Photo Winner!

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    Bumping this thread because haven´t been able to solve the problem thus far!

    I replaced the accelerator pedal, the oxygen sensor, had the throttle body and the injectors cleaned but no results.

    I was thinking about replacing the lamda probe but i don´t know since there seem to be more than one in the car.
    I´m a little confused about what to order!


    Some mechanic told me that it could be converter slip and that it´s normal for the rpms to drop when the converter clutch closes - dunno about that.
    I then had the transmission fluid changed to see if that does anything, but still no results.

    Can anybody with a V6 with the 5 speed chime in and tell me if your cars are doing the same thing.
    If others have that behavior too, i´d be willing to accept it as normal behavior - so, i´m a little sceptic!

    Or if anybody else with technical skills has a suggestion what to try next, i´d be more than happy...
     
  3. djalbin

    djalbin Active Member

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    Engine RPMs will drop when shifting up from one gear range to another. That's because you're going to a lower gear ratio. I don't have the V6 so I don't know if the RPM drop you're seeing is normal.
    Your experience with the dealership is typical when it comes to diagnostic trouble codes ... the Service Technicians are trained on diagnosing problems using the DTCs. Unless there's a Technical Service Bulletin (TSB) describing a particular problem/symptom, they really don't have anything to troubleshoot/diagnose without a DTC.
    RPMs can lower when the lockup clutch, in the torque converter, is engaged ... but most of the time it's not noticeable with the factory stall speed. There's fluid slippage in the torque converter until the lockup clutch is engaged. So the engine RPMs will increase with the slippage until the lockup clutch is engaged; then the engine and transmission are directly connected. This is suppose to occur when slippage is no longer needed. It's possible your lockup clutch is engaging earlier than it should ... but it's just a guess.
    Was the dealership able to determine if you have the latest PCM/TCM software? Sometimes getting the latest software helps with drivability issues.
    .
     
  4. freakzilla

    freakzilla Member Photo Winner!

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    Nah, has nothing to do with a gear change - the RPMs drop during the acceleration process within the same gear.

    Here´s a quick video to show what i mean:
    http://de.tinypic.com/r/344a45d/9

    Having to slow down before a right turn, entering with about 1000 RPM, accelerate with easy press on the pedal and when it hits about 2200 RPM it drops down to about 1800.
    I did not upshift there - everything happens in 3rd gear with Autostick!!!

    Does that everytime i have to slow down and then accelerate back up.
    It doesn´t do it when i start accelerating from a stop.
    It doesn´t do it when i accelerate WOT.

    Had all TCM/PCM updates made and had the dealership reset the PCM adaptives and i did a TCM reset with the TranZformer.
    Didn´t make much of a difference!


    Maybe that is normal behaviour of the V6 converter clutch - that´s why i´d live to hear from other V6 drivers too.
    I think it´s annoying tho...
     

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