weird acceleration

[AKPsiMC03]

weird acceleration

okay.. today the traction control was on alot when i was trying to get my car free from the snow.

So it was going on and off for about 20 min while i was working my way out.

It stalled a few times during that too.

but.... not when i accelrate, over 2,000 RPM in any gear it feel like one fo the cylinders is missfiring. The tach stays normal, but it doesnt feel right.

Could it jus tbe because the roads are a little wet so the traction control is still on? or could i have broken something? when the traction control was doing its thing in the snow there was an occasional clunk coming from up front. I though it was the brakes doing its thing to work with it.

Help me... it feel very unright and i don t want to burn up an $8000 motor on a car ive had for 2 weeks.

[elwesso]

It is the traction control. I have the same deal on my GTP, and its brand new. Is it where you hit the gas and it like bogs down?? That is the traction control. The PCM actually limits the amount of torque that gets to the wheels by applying the brakes. If the car detects slippage, the TCS stays on for about 5 more seconds after traction has been regained. I am not sure about this clunking thing you are talking about, but i would assume it wouldnt be anything to worry about unless it does it all the time.

I hoped that helps, if i didnt cover something let me know!!!

[Devil_concours]

when the traction control kicks in, it controls brakes and the engine output.
Basically it takes the power away from the driver and uses individual brakes to regain control appropriately.
You can hear a lot of clunking sound from the brakes on severe weather. Try it in any car with abs.

Also you guys should test cad's traction control while you still have snow available. It's amazing. At low speeds turn the steering wheel quickly, when you feel the car moving hit the brake hard as you can.

[elwesso]

Yeah, i forgot about the ABS, that could be the clunking.

The traction control on the GTP is great, but im sure it is much better on the cadillac.

BTW, the snow isnt going anywhere anytime soon here

[AKPsiMC03]

this probelm only happend on very light acceleration and is immidiate as soon as the tach reaches 2000 rpm. THe tires dont spin before it. Hopefully it will be dry tomorrow so i can test it better.

[elwesso]

Was the engine fully warmed up, sometimes it could do that if it is cold

[AKPsiMC03]

yup.. but its never done that before... even when the coolant temp was 38 degreese

[elwesso]

Maybe it has to do with the relative humidity, and the barometric pressure???? .

This doesnt sound like something to worry about.

[Devil_concours]

Originally posted by AKPsiMC03
this probelm only happend on very light acceleration and is immidiate as soon as the tach reaches 2000 rpm. THe tires dont spin before it. Hopefully it will be dry tomorrow so i can test it better.

my traction control kicked in while i was driving on patch of snow in the neighborhood (25mph). I'm guessing that's what happened to your car. Traction control kicked in eventhough there was no wheel spin

[jadcock]

The traction control attempts to control the wheelspin, usually by applying an individual wheel's brake (or both, as necessary). It does this through ABS modulation, so it'll have a rumbling sound as it's doing it. It should also display "TRACTION ENGAGED" on the DIC (the Driver Information Center). This is the message to you to not get alarmed, the car is simply doing its job.

The traction control can also request a torque modification from the engine, where it cuts certain cylinders, but this is in a severe situation where the brakes have been overheated (the ABS "guesses" at the temperature of the pads as it applies the brakes -- the newer models actually have temperature sensors at the pads I think). Again, the traction control system only requests a torque modification from the engine after it thinks the brakes are over worked. In other words, it'd be hard to do this. Maybe if you sat on ice and spun them for 10 minutes straight or something. Or maybe a severe case of rocking the car, trying to get it out of snow. But normally, you would never have that happen to you (torque reduction).

Another note -- if there is no wheelspin, the traction control does not engage. Period. How would it know to engage...and what would it be controlling if there were no wheelspin? It's actually fairly liberal -- it will allow up to about 10% wheelspin. You can chirp the tires and scuff them a little bit during acceleration without the traction control activating. Check it out on dry pavement. Practice a little bit with it. If you floor it right out, you'll probably spin them outright, and activate the traction control. But with practice, you'll get the tires to chirp or squeak off the line and you zoom away, with nary a "TRACTION ENGAGED" message on your DIC.

[elwesso]

Good info, Jason. You always have the right answers.

[Devil_concours]

maybe there was a small wheel spin that you just didn't feel or there was a bump(snow) which caused the car to think that it's about to lose traction.

[AKPsiMC03]

it feel like its cutting fuel and/or spark to one of the cylinders... i cant figure out why. It didnt do it until before i tried to get out of the snow...

[Devil_concours]

i think i had a similar experience where the car wouldn't go over 2500rpm (i was testing out my traction control). It is said in most traction control system description that traction control has the ability to control individual brakes and engine output.

[elwesso]

If it was doing that, it would run weird all the time, not just under light acceleration. I think i know what you are trying to explain. The only thing i can think of (besides the TCS) is that it may be running too rich. That makes sense, because it bogs down until it burns off the eccess fuel, and then resumes normal operation. Try and see if you can get your o2 sensors checked, and check for codes.