Transmission Hesitation or Traction Control? Anyone else experience this?

[rcryniak]

I've been noticing since I got this car, that in situations where I go WOT from a rolling start, sometimes it takes nearly a second for the big "whoosh" of power to kick in and make this baby go. It never happens from a dead stop, only when already going... I'd say at least 15-20mph. It's happened maybe a dozen times since I've had this car. (Two months?) Just push the throttle all the way down, and it's like "wait, didn't I hit the gas??", and then "ooohh, there we gooo!"

My best theories are:

Theory #1: This is totally normal, and the traction control system is kicking in and saying, "nope sorry, can't help you, you're about to slide off the pavement!" However, road conditions are fine (dry, flat, etc.), tires are in great shape, and I can't imagine breaking the tires loose in this situation if traction control were disabled... but I suppose it's possible?

Theory #2: Transmission needs serviced - but I haven't noticed any slippage or anything else in any other situation. (There was a question with slight drag on coasting, but someone pointed out it's normal, and even mentioned in the owner's manual.)

Theory #3: Fuel system isn't able to give me enough at the moment, which is either normal, or not and needs serviced. This I doubt very much, since the RPMs definitely go up as soon as my foot goes down... just no push to the wheels for the second. Perhaps it's not really going up as much as full throttle would other wise be asking for, which is why I'm not tossing this theory out entirely.

Theory #4: Some sensor is malfunctioning and needs serviced.

Also, I'm not getting any DTCs or pending DTCs. Dealer techs say the car's in great shape.

Any thoughts or ideas? Anyone else experience this, or something similar?

 

[rcryniak]

Oh, and I'd be happy to hear anyone's experiences with any sort of hesitation, or anything where you got a response from the car that was different than you expect. Your experiences will help me learn this car's habits faster than figuring it out on my own, so thanks in advance!

 

[jmr061]

Make sure all the computer modules especially the PCM are up to date on their programming. That is always number one. After that it is sensor or mechanical issues. Its amazing what programming can do. I would suggest looking into getting the tune in the car and seeing if that solves it.

Jason

 

[rcryniak]

I'm pretty sure the PCM is up to date. The code matches one of the ones listed at motorcraftservice.com. I didn't want to install the tune until (a) I've run my "before tuning" tests with datalogging, so I can compare with the "after tuning" data, and (b) I know for SURE that there's no lurking issues that tuning could bring to light... because once the tune is put in, my powertrain warranty goes bye-bye. I feel very confident with the LMS tunes, apparently they've had a zero failure rate... but I'm a software engineer, and every fibre in my being is telling me to know before I go.

Are you saying you've never once experienced such a delay at WOT while already driving? (Again, never had even the slightest pause from a dead stop.) Not even from traction control telling you "no"?

The weird thing is that if the transmission slipped, I'd expect to feel the car disengaged and begin to coast, but it's more like the wheels are waiting a second to catch up to the engine. I guess I want to know if this is normal behavior for stock.

 

[jmr061]

Tuning will not automatically void your warranty. This has been discussed in detail. The tune has to cause the failure, sure that is possible but many people have had warranty work done with cars that have been tuned.

Put the tune in and see if it goes away. You can always put the stick tune back in.

Jason

 

[broke1]

It's the hesitation from a drive by wire throttle vs drive by cable.Lots of newer cars do this,Ford,GM,Dodge,Mercedes,Toyota,any car with dbw can experience it at times....put in the tune and it'll never happen again because every tuner I know tunes this out.

 

[rcryniak]

SOLD!! Thanks guys :woo-hoo:

...I'd still love to know if anyone else has had any weird issues that might come up, just so I know ahead of time what to watch out for.

 

[brucelinc]

Getting a tune is a great way to get more enjoyment out of your SHO. By all means, do it!

Regarding the situation you describe: Definitely not traction control. When that engages, you will know it. Besides, flooring a stock SHO from a roll will not break the tires loose anyway on dry pavement. Not a transmission issue, either. If that were the case, the engine would rev up but you would not be going anywhere.

The drive by wire answer makes sense but I have never experienced the delay that you are describing. There is a split second of turbo lag but it is very brief. If you are going 15-20 MPH, it has probably already shifted into 2nd. Flooring the throttle would cause a kick-down to 1st. There is a delay built into that to make the downshift smoother. That could be what you are feeling.

 

[TheDailySHO]

Does it go away if you completely turn off advancetrac and enter sport mode? You have PP so you can push the control button twice quickly and completely turn it off? I'd be curious to see if that changes what you have experienced.

 

[Calgary]

i agree with bruce I think people underestimate what gear there in cause of the economic upshift is seems. the cars always trying to get into 5th.

 

[rcryniak]

Tests completed, tune installed... VROOM and CLUNK.

Does it go away if you completely turn off advancetrac and enter sport mode? You have PP so you can push the control button twice quickly and completely turn it off? I'd be curious to see if that changes what you have experienced.

I normally don't drive around without traction control... I leave it on unless I'm running performance tests. (So I really don't know!) However, just FYI to others just getting into a PP, you hold the button for about 10 seconds to turn it completely off. Hitting twice is sport mode.

i agree with bruce I think people underestimate what gear there in cause of the economic upshift is seems. the cars always trying to get into 5th.

Soooo true. The car seems to live for 5th. It's favorite flavor. Not sure now with the 4+ tune I just installed - will have to pay attention to that.

SO... I did it. Got my tests done, data logged, a couple 0-60 runs, installed the tune, repeated. 0-60 times improved by 0.51 seconds... very nice. The shifting is definitely more noticeable, more confident, and there seems to be a feeling of more power after every shift. Just awesome. :woo-hoo:

However, after running my tests, I took my 11 year old daughter (who loves this car too) for a test drive, did a 0-speed limit test after a stop light going onto a traffic-less highway. (She loves doing that.) It was great. She loved it. Once up to speed, we cruised down the road for a bit, waiting for the first turnaround, and some guy in an old beatup pickup truck started to pass us by. I was perfectly content to let him do so (I'm not stupid with my car, however much I love to accelerate ) so he was passing us. Then he was suddenly drifting into us... I hit the brakes, so we didn't hit. (Thank God... that actually happened to me a week into owning this car, someone side-swiped me on the highway grrrrr! $2000 in damage!) Anyhow, this time there was plenty of room, no one behind me, so I avoided nicely.

Here's why I'm telling this story... when I resumed acceleration, I heard (and felt) a bit of a bump (or a clunk), as if from the back wheels. (Definitely felt like it was underneath and behind me.) The car performed as expected, and the bump/clunk occurred precisely at the very instant we started accelerating, as if something was "catching" to go forward. Nothing bad happened before or after, the car's driving just fine, so I'm not worried about it really... but I am curious if that's indicative of a problem of some sort, or if it's normal after a tune... perhaps it was just the wheels kicking in, I have no idea, honestly.

I've emailed Anthony at Livernois asking his thoughts on this, hopefully I'll hear back tomorrow. Any thoughts/theories from any of you?

EDIT: Almost forgot, I did notice a bit of acceleration lag one other time (after the tune), but it was very, very short. (Guessing 1/4 second?) A great improvement.

 

[brucelinc]

There is a transmission adaptive learning routine after a tune or any reflash. The shifts will remain crisp and firm but it will smooth out and work better after 150 miles or so.

 

[SHOdded]

I would also check out the RDU fluid level just to be on the safe side, especially if you feel/hear that bump/clunk again. It's not infallible.

 

[rcryniak]

forgive my ignorance, still new to all this (but learning!)... RDU?

 

[SHOdded]

Rear Differential Unit. Controls power to the rear wheels, kinda like a mini PTU.

Go here, click on the infotrac URL, then on the PROCEED button, pick your vehicle (I think only up to 2011 Taurus repair info listed?), then Repair.

Look under Driveline - Rear Differential for more info.

 

[rcryniak]

Awesome... thanks man. I'll check it out in the a.m.

 

[Boggus]

Even with a tune there is a slight delay. Normal cruising at 35, then nail it - takes the car a brief moment to decide what to do.

 

[rcryniak]

SHOdded... that required library access... so I wound up paying for a subscription directly from Chilton, which is fine - good info as far as I can see so far, so totally worth it.

Boggus... thanks!! That's very useful to know.

 

[SHOdded]

That link should've been free. You clicked on the INFOTRAC URL near the bottom, right? Maybe I have the info cached on the browser. Will check.

EDIT: I guess you'd have to pay to get 2012+ repair data from Chilton. But yeah, can't go wrong with a subscription. They give you tsb access too, which is pretty nice!

 

[rcryniak]

I don't think I was completely awake yet. Didn't click the link... and I just tried it and it works. Oh well. Subscription was cheap enough, lol. (sigh) No big.

I've been reading up on various websites and forums about rear differential clunks, and the conditions and explanations of other's experiences of RDU clunks/sounds don't quite match. (I don't think anyhow.) I also read that you're supposed to disassemble the RDU to drain it... and then replace the fluid. If there were a dipstick, I'd say that'd be easy to check, but I've gotten the impression that the only way to check it is to replace it.

So, that kind of thing is a touch beyond me at the moment... and in lieu of going to the dealer with what may very well amount to be absolutely nothing... I should probably clarify about the bump/clunk, it could very well be perfectly normal. (Being new to the car, and even newer to tuning, I'm still learning what to expect from my SHO.)

The noise had virtually no tone/pitch to it, didn't sound hollow, or particularly mechanical. It was arguably more of a feel than a sound, like the rear wheels were suddenly and immediately engaged, and there was a feel of a "bump" as the rear wheels were kicking in... like there was an instant in time when they suddenly had power that wasn't there before. I suppose the best way to repeat the sound itself would be to make the sound "Thp!" with your mouth, using minimal vocalization. Another way to imagine it would be if someone kicked one of your tires... just an instant of "Thp." Anyhow, at the very instant of the sensation & sound, power was applied to drive... at the precise moment power was applied to the wheels, and the car began to accelerate. The power to drive was absolutely consistent with what I expected at the given throttle position (about 50% down)... which is one of the reasons I wasn't worried, the car behaved completely normally, as far as drivability goes. The noise was so minor I simply assumed at first it was the tires catching the pavement after applying some power after a relatively hard brake.

Whew... it's really, really hard to describe some things, you know? lol. Anyhow, if this still sounds like a rear diff problem, then I'll get it checked out. However, if this just sounds like the sensation of the rear wheels suddenly being engaged with some power after quick deceleration, than I'll just know to expect it under those conditions. ...which hopefully won't happen too often.