Accelerating

[97ponygt]

I have only had my Mustang for about 4 weeks and I have another set of questions to ask... My first question is this, Whenever I gun my car is doesn't always have the same feeling of acceleration, and by that I mean when I put it pedal to the metal when I'm going 20mph is feels like it accelerates faster than when going 30mph. I have an automatic tranny and my car has 75,000 and it's a 97, and the person before me who had it had it tuned with a diablo tuner and had it shift at 5500rpm which leads me to my next question...

Why when I gun it, it doesn't always shift at 5500rpm? It seems like its always the speed at which I gun it which dictates the rpm at which it shifts.

My last question isn't a big deal (I don't think) but why does my car smell really bad like crap after going pedal to the metal? Is that anything to worry about? Thanks for all the help and I hope these questions make sense, if not let me know and I will try to reword them so that they do. Thanks!

 

[FoxRod87]

Does it downshift any when you accelerate or does it stay in the same gear at both speeds? Not sure about the shift points. And it shouldn't smell bad after accelerating hard. What does it smell like? (rubber, shredded belt, or transmission)

 

[97ponygt]

I've never paid attention to what gear it was in, duh? But I'm pretty sure that there different, and the I'm not sure what a transmission smells like but it kinda of smells burnt. I can't really give you anything more specific on the smell and the smells not really that strong.

 

[evil281]

maybe hes got the shift points all messed with(previous owner)

 

[97ponygt]

Smell

I accelerated hard again today and there was a little squel kinda of like a dry belt sound in the winter but it only lasted maybe a second... Then the smell again and it smelt like something was burnt... Maybe it's a belt do you have an idea as to what belt it might be?

 

[CobraRed_96_GT]

That's the accessory drive system trying to slow down to the crank speed in between shifts or after hard throttle. Sometimes belt slip is necessary to reduce bind and load on parts that are carrying rotating momentum - but you can get a gatorback belt if it bothers you.

 

[SVT32VDOHC]

Going 20MPH an auto Mustang will downshift into 1st gear and take off.

Going 30MPH an auto Mustang will NOT downshift into 1st gear and take off, it will stay in 2nd gear.

30MPH is an awful speed to do that to the transmission. 45MPH is good, 60MPH is good, but no 30MPH. I wouldn't do that 20MPH downshift too often, my trans took a dump on me after a lot of that.

 

[nyuk98gt]

97ponygt:

WOT 3-4 and 4-2 shifts are very, very bad for the auto trans (4R70W). Turn off O/D before stomping on the gas pedal. If the fluid is dark or smells burnt then change it and the filter. Install a tranny cooler (get a big one), too.

Read all about your trans in "Transmissions 101" at TCCoA.com (then Tech Articles/Transmissions). Jerry Wroblewski (author) is a former Ford Transmission Engineer who had a big hand in the 4R70W development.

Shifts are controlled by the PCM based on MPH (vehicle speed) or RPM (engine speed), depending on how the schedules are set up.

HTH,

Chris