Hard Downshift on WOT

6469 Views 9 Replies 7 Participants Last post by rob-2, Mar 9, 2015

neuroticdave

Discussion Starter · Mar 8, 2015

So I finally got around to disconnecting my car battery and resetting the cars parameters. Once plugged in, I took it out for a "lively" drive on the highway. I used Autostick to give her some healthy WOT runs, but at one point I left it in D @ 65MPH and just mashed it.

Well, the ultimate result was not very nice. It THUNKED it's way down to 3rd gear. I then decided to use Autostick again and left it in 4th and decided to downshift and once again, THUNK.

I tried another WOT run from D and same result, a rough THUNK down to 3rd. At another instance I used Autostick to get into 3rd and gave it some light to mild mashes of the gas, and it was quite rough.

Is there something I should look into in specific to fix this? Or was the battery pull the possible culprit, and the car just has to learn it's way around? I just bought the car a week ago, but this is the first time I've opened her up like that.

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djalbin

· #8 · Mar 9, 2015

I'm not familiar with all the MY's for the Charger R/T but I know with the later models there is some communication between the PCM (5.7L engine) and the TCM (NAG1 transmission).

The PCM controls the engine in closed-loop mode when not WOT (i.e. PCM uses the input from various sensors to control the engine ... and is also communicating with the TCM).

The PCM controls the engine in open-loop mode when WOT. (i.e. PCM is not using any input from the various sensors and is just controlling the engine using the WOT mapping ... and I assume is not communicating with the TCM).

So what's my point ...
Closed-loop mode is going to produce smoother transitions between the engine and transmission (PCM and TCM are working in unison).

Open-loop mode is going to produce rougher transitions between the engine and transmission (PCM and TCM are working independently).

Quick transitions back-n-forth between closed-loop and open-loop modes is going to produce rough transitions (PCM and TCM are thrashing until they are in a steady state again). The behavior of the transmission when going WOT will depend on the speed/gear the car was in when going from closed-loop to open-loop.

So as some of the other posts suggest ... your car may be performing as expected.

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