[Tanky]

I posted this on lxforums.com and got a few answers, and I wanted to post here and see what you guys have to say:

Ok, maybe I'm a little off my rocker but I was wondering about an issue (well if you want to call it that) that my car does. Why is it when I'm cruising along, whatever speed, and I get on it (not hard mind you-maybe enough to get next gear), the car accelerates but does so like I'm riding the cluth. It feels like when it goes do, it "gradually slides" down, like I'm riding the cluth til my foot is off the thing. Is this the torque management deciding to not unlock? Its really annoying to hit the gas and I hear the car, but nothing really happens except minor accel for 5-10 seconds then i get a small surge and the car goes. I've noticed this more and more with the new exhaust probably due to being able to hear more now. Anyone have any ideas what this is, and how to fix it? Does the programmers out there, or B&M, or even the Mopar PCM piece?

I also asked this about the SC programmer, since people said this would fix everything:
This SC thing, will it do anything for the delay in changing gears? In other words, R to D, or D to R? Seems to take a good 10 seconds before in the gear i selected??



Basically those on lxforums recommend the SC programmer for the car. I'm slightly afraid of the 91 octane requirement. I spend my mornings in stop and go, and most of the day in the same thing. My Mileage averages 13.5-14.5 due to the constant 1-2 gear hang outs.
Does everyone else feel the SC is the best thing going to address the issues I feel I have? Or something else? Someone mentioned about getting a non flashed SC...but not sure why. Anyone?

 

[wickedchargerrt]

whats a cluth?

 

[Ladybreeanna]

whats a cluth?

LMAO I am glad you did it first!!!

 

[fluffykush]

drive-by-wire system. google it and see other cars having the same problem.

 

[TripleTransAm]

Does this usually happen in a higher gear?

If so, it should be the PCM (TCM?) programming slowly unlocking the torque converter. Not having poked around the ALDL stream I'd have to say it's part of the stock programming. Seems like the programming makes for a gradual unlocking of the torque converter as power is requested. Most likely for fuel mileage reasons, as completely unlocking the TCC might bring more RPM than would be needed for gradual acceleration.

A lot of a car's stock programming (especially an automatic) comes from trying to meet specific details of the EPA tests. Sometimes it's a matter of what seems like poor shift points when in fact it's done on purpose to get the car into a certain higher gear at a certain test speed within the EPA's test. Ironically, in some cases this can hurt real world mileage... in other words, in the real world a driver would get better fuel mileage by manually extending the shifts a few hundred more RPM... but if the EPA test says 40 mph cruising for x time, then it is probably beneficial to get the tranny to the highest gear possible at 40mph.

So in this case maybe there is some EPA test that involves partial acceleration at those speeds, and there is a benefit to control the amount of unlocking in a gradual fashion to meet that acceleration requirement?

So I'd say it's normal.


In any case, not that it would help you in your neck of the woods, but for winter driving I appreciate the slow unlocking (to avoid shocking the driveline and possibly losing traction in snowy conditions). My 2 previous cars (both the same model, same year, everything) had a tendency to hold on to highest gear and full TCC lockup until the very last millimeter of pedal travel and then explosively drop a gear or two with the TCC full unlocked... talk about violent driveline shock! Not very refined at all. On the contrary, if it wasn't for my Brylcreem'ed exhaust, I'd hardly notice the increasing "slippage" of the TCC.

In any case, I've never been a big fan of slipping clutches, so if I foresee a need to giddy-up I usually manually grab a lower gear (which by nature forces a complete TCC unlocking immediately).

 

[Tanky]

Clutch!!

I don't like this feeling transAm. At any speed, cruising, I depress the pedal, hear the motor RPM up, but the car barely does anything. Few seconds later the care goes. The only way I can explain it is it feels like I'm in 5th gear, downshift to 4th gear but keep my foot on the clutch. Do this for a few seconds then finally come off the clutch.

 

[xring]

I think it is the torque convertor unlocking. Mine does the same thing; if I slap down one with AutoStick the rpm rises; if I then slap up it drops. So it is like I'm between two gears (ratio-wise). Pretty sure this is the torque convertor unlocking and it is normal.

At least I hope it is normal.

 

[TripleTransAm]

Clutch!!

I don't like this feeling transAm. At any speed, cruising, I depress the pedal, hear the motor RPM up, but the car barely does anything. Few seconds later the care goes. The only way I can explain it is it feels like I'm in 5th gear, downshift to 4th gear but keep my foot on the clutch. Do this for a few seconds then finally come off the clutch.

Except in this case, the RPM would climb until your foot came off the clutch and then drop a bit as the clutch fully grabbed, no?

Anyway, I think we're talking the same thing. It doesn't happen to me all that often (either I get enough acceleration without the car needing an unlocking or I'm already at the speed I want when I'm merging or maybe I usually prefer manually downshifting instinctively as I think to press the accelerator... I don't know which is the case with me).

Can't say if aftermarket tuning would help with this. (ie. does this behaviour come straight from the TCM or does the PCM hold the ultimate logic here?).

I know there was a new TCM calibration that was released for the 6.1 cars that a lot of 5.7 owners ended up taking (the TCM is the same part number, supposedly). I wonder if this behaviour was changed?

 

[Gabe]

Acceleration similiar to riding a cluth??

You mean clutCh ?

 

[OSUthunder]

I dont know what your talking about with the clutch thing, unless your talking about downshifting and turning, then the computer will kill your torque so that you dont spin your tires if you gas it. (try running with esp off)

as for the D -> R or R -> this IS your tcm. ive noticed that if I put the car from one to the other and my RPMs are up over idle, you can specifically correlate how high over idle vs how long it takes. backup, STOP, shift. it shouldn't take more than a second to start moving forward. ive noticed also that the TCM SEVERELY limits the amount of power you can put for about 2 seconds after a R -> D shift. after that I take off like a bat out of hell.

 

[Tanky]

You mean clutCh ?

yes we all have jokes today.

 

[Gabe]

yes we all have jokes today.

I'm actually having a horrible day at work, yesterday was bad, today is worse, to the point that I really don't wanna come here anymore ... I wanna just leave without telling anybody anything and just not return ...


Sorry for hijacking the thread

 

[jeeplaw]

Ouch, gp, it'll get better Then again you are in MASS (I'm originally from CT)

To the OP, I get the same lack of acceleration and then surge too..and it's more noticeable within 5 mins of startup.