HELP. Strange Sluggish Acceleration

[Composto86]

Try it with all the nannies off - not just the toggle for TC (hold it for like 10secs or whatever the wait time is)

Yeah ive tried that... same same.

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[Composto86]

Did you shift right at the start of that video? Maybe your clutch pedal sensor is off.

Clutch was out for a good 5 seconds before the video started.

It only does this in second gear.

 

[Composto86]

Have you made any changes to the as-built configuration by any chance? (Using the FORScan app with a OBDII adapter.)

I had a problem similar to this after I changed the tire size setting to get my speedo showing the correct speed.

For whatever reason, it was confusing the ABS/TC system so the car was pulling power. Once I changed the as-built data back to a factory tire size, the issue went away.

I have not... 100% stock.

 

[nastang87xx]

Definitely take that in and have their best tech, preferably a Master, ride with you. First time I listened to your video I was thinking uh oh...my guy is only firing on 7 cylinders. But I'm not sure about that now. Either case, take it in, get it METICULOUSLY diagnosed with yourself in the process.

 

[Helmet]

Disconnect the Battery and let it set for about 30 minutes then reconnect it.

 

[Trackaholic]

There is a significant jump in torque between 3000 and 3500 RPM in this car. Not sure what causes that, but the jump is so discrete that I strongly believe it is a controlled event (valve timing change, intake charge control valves (can't remember exactly what those are called) or something like that). Since you are flooring it right in the middle of that range, I wonder if whatever makes that torque change isn't getting activated some of the times.

Let us know what you find out.

-T

 

[MrCincinnati]

Yeah ive tried that... same same.

Interesting. If it doesn't rain after work tomorrow I'll try to recreate on mine. One thing you said - sport or regular mode. What about track mode?

 

[rb92gt]

I've noticed something similar, although maybe not as drastic and not 50% of the time. Sort of feels like something is spooling or an automatic transmission is trying to find the right gear for a split second before all hell breaks loose and can feel the horsepower I would expect. Definitely can tell more electronic nannys and sophistication involved in this car than other NA manual cars I've owned. There is never any delay when I press the accelerator in all 140,000 miles I've put on my old fox body mustang (Manual Trans, NA as well). That car feels like it has gobs more torque than my GT350, even though number wise it doesn't.

 

[Composto86]

Interesting. If it doesn't rain after work tomorrow I'll try to recreate on mine. One thing you said - sport or regular mode. What about track mode?

I really don't mess around with track mode on the street (suspension is just way too stiff for Houston roads. BUT it wouldn't surprise me one bit if it still did it.

Thanks for giving it a shot.

 

[Composto86]

I've noticed something similar, although maybe not as drastic and not 50% of the time. Sort of feels like something is spooling or an automatic transmission is trying to find the right gear for a split second before all hell breaks loose and can feel the horsepower I would expect. Definitely can tell more electronic nannys and sophistication involved in this car than other NA manual cars I've owned. There is never any delay when I press the accelerator in all 140,000 miles I've put on my old fox body mustang (Manual Trans, NA as well). That car feels like it has gobs more torque than my GT350, even though number wise it doesn't.

Prior to figuring out how to recreate it, Ive only noticed it twice in 4K miles.

But now that I can duplicate it, id say 50% is accurate.

 

[ldp82]

mine has done this. If I am costing at 2-3k RPM in 2nd or third just touch the throttle a few times quickly, then floor it. I thought it was due to me messing with air fuel ratio from no throttle to tip in then full throttle.

 

[MrCincinnati]

I really don't mess around with track mode on the street (suspension is just way too stiff for Houston roads. BUT it wouldn't surprise me one bit if it still did it.

Thanks for giving it a shot.

NP - weather looks fine so I'll check it out in a couple hours.

FYI - you can throw it in track mode then change dampers to sport

 

[Eric0w]

If you look at the dyno sheets, the torque doesn't really kick in until 4k rpm. So just downshift another gear when you wanna pull fast.....

 

[MrCincinnati]

I was able to recreate this pretty easily. The first attempt in normal mode exhaust opened up automatically and it pulled hard as hell. The 2nd attempt exhaust opened up but it did pause first. Also tried in track mode and it didn't stutter but it definitely didn't snap my neck back like the first time. What I did notice and didn't have the chance to test was - the times it hesitated I was coming down from above 3k. The time it pulled hard I eased up to it and punched.

It feels like TC to me. I'll play with it some more later to see if I can get consistent power by easing the throttle on before wot versus easing off first.

 

[agentscreech]

I've noticed that if the car is in sport mode, the throttle response is much snappier. In normal mode, it's trying to read if I want to fast or not, so sometimes if I got on it, it would go like normal, other times it took a second then the computer finally decided to open up the flood gates. It felt similar to what the first post did. It was certainly not TC, I never spin the tires in a straight line in the dry.

There could be something to the computer algorithm where it reads how you are driving and adjusts accordingly. I think it's similar to the way computers deal with DCT. If you are accelerating in 2nd gear, the computer will select and spin up 3rd gear in preparation for the shift so it can do it lightning fast. But if you decided to downshift instead (god know why you would...), it has to switch out 3rd for 1st then activate the shift so it takes longer.

Maybe the computer in normal mode is doing something similar? If you are not driving hard, and just idling down the road or even decelerating, it's not ready to adjust the fuel and timing to go WOT, but in sport mode it is ready to go at a moments notice.

When I first got the car, I played around with the different modes. I thought that since Sport Mode (selected by the Mode+ button) activated the sport exhaust but put the shocks and steering feel to sport as well. I like the shocks and steering wheel in normal, but the exhaust in sport. So instead of hitting like 10 buttons to get it the way I want it, I would just hit the sport exhaust and continue about my day.

Later it dawned on me that putting the whole car in sport mode does more than open the exhaust, stiffen the shocks and steering. There are throttle response differences too. So now I've just gotten used to hitting Mode+ x2, shock button x2, hit ok, then hit the steering button x3 every time I drive (until someone figures out how to mod the cpu to default to this mode).

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