: weird acceleration



AKPsiMC03
02-18-03, 07:20 PM
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
02-18-03, 07:29 PM
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
02-18-03, 07:48 PM
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. :D

elwesso
02-18-03, 07:52 PM
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 :D

AKPsiMC03
02-18-03, 07:54 PM
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
02-18-03, 08:05 PM
Was the engine fully warmed up, sometimes it could do that if it is cold

AKPsiMC03
02-18-03, 08:31 PM
yup.. but its never done that before... even when the coolant temp was 38 degreese

elwesso
02-18-03, 09:03 PM
Maybe it has to do with the relative humidity, and the barometric pressure???? :D .

This doesnt sound like something to worry about.

Devil_concours
02-18-03, 09:39 PM
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
02-18-03, 09:48 PM
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. :thumbsup:

elwesso
02-18-03, 09:51 PM
Good info, Jason. You always have the right answers.

Devil_concours
02-18-03, 09:52 PM
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
02-18-03, 09:52 PM
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
02-18-03, 09:55 PM
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
02-18-03, 09:58 PM
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.

jadcock
02-18-03, 10:08 PM
Let me make a follow-up to my original post -- I sent that before I should have.

The traction control system (let me abbreviate it TCS) has two priority levels, traction and directional control. At low speeds, if wheel slip is detected, it will maximize traction. There is usually no torque management occuring at low speeds, just brake modulation. At high speeds (above 50 mph), if wheel slip is detected, it will maximize directional control. There is no brake modulation at high speeds, only torque management.

The TCS engages only when the system detects one or both front wheels is losing traction. When excessive slippage occurs, the system will engage.

If the Eldo in question was traveling above 50 mph, it is possible that torque management was engaged. For the record, it can cut fuel (the spark continues) to as many as five of the eight cylinders. I can feel the torque management when I'm racing up or down a curved interstate entrance. If it's wet, I can feel the front of the car push a little bit and the tone of the engine will sometimes change and I can feel the front of the car pulling back in the direction that I'm steering very slightly.

If you are going fast (above 50 mph), this may be the cause of your engine symptoms. If at a slower speed, I would guess it's something else. It just doesn't sound like the TCS in action.

elwesso
02-18-03, 10:12 PM
But even when the brakes are applied in the lower speed TCS, wouldnt it give it sort of that same feeling-- that the engine is struggling?

Devil_concours
02-18-03, 10:12 PM
if that is the case then i need to get my car checked. It was doing something similar to what he's describing (in the snow).

elwesso
02-18-03, 10:15 PM
I dont think so, i think that the car is just doing its job.

AKPsiMC03
02-19-03, 12:59 AM
could this be a tranny shudder? i know 94/95 tbirds had a simmilar problem so ford developed a new fluid that eliminated the problem.

should i get the tranny flushed and see if that helps?

jadcock
02-19-03, 09:43 AM
When the brakes are applied, it'd sort of give the same feeling, but it'd be real apparent that it's modulating the brakes because of the rumbling of the ABS equipment. It's possible it may be something in the transmission. Have you pulled the codes from the vehicle?

AKPsiMC03
02-19-03, 10:09 AM
it doesnt feel like the ABS cus when it does it when i accelerate ther eis no break noise. All i get is a surging kind of like when my little brother's 383 wasnt firing all 8 cylinders.

how do i pull codes on a 95 (pre OBDII)

AKPsiMC03
02-19-03, 05:15 PM
probelm solved.

The pugs looke dlike the original plugs. they were all white ont he end and had gaps between .070 and .10! :eek:

so i put new plugs in, and she runs like she is brand new.

i also finally fixed all my deads lights while i was at the parts store. lol

elwesso
02-19-03, 08:16 PM
DID YOU THROW AWAY THE OLD PLUGS???

They are platinum tipped, and should last forever. Just re gap them, clean em up a little and theyll be as good as new. They should last the life of the car.

AKPsiMC03
02-19-03, 08:48 PM
i kept them... but 2 of them have cracks in the ceramic on the necks with burn marks around the cracks. so Im guessing those two are no good.

but i still have them.

elwesso
02-19-03, 08:52 PM
yeah the screwed up ones will be trash, but keep the rest. What did you replace them with???

AKPsiMC03
02-19-03, 09:05 PM
autolite copper clugs for 3 reasons: one they will work with the car, 2, they were cheap and i was short on cash today when the car started stalling from the bad plugs, and 3, i run them in everyhting and never had a problem with them.

elwesso
02-19-03, 09:41 PM
Good enough for me......

jadcock
02-19-03, 10:34 PM
I wonder if the constant use of traction control somehow overloaded the brakes and caused the engine to start cutting fuel. And somehow the lack of fuel caused the spark plugs to overheat and fail? That's interesting...sounds like severe damage to them if the insulators were cracked! Good call on replacing them. Elwesso's right -- they're platinum and should last essentially the life of the car. Mine are almost 112k miles old and the thing still lays waste to anything short of newer V8 Mustangs and Camaros.

Speaking of which, I saw some ghettoed out '96 Mustang today...V6 model. Had the Altezza something taillights and wheels. His license plate said XTREM96. After I wasted him from one stoplight, I wanted to roll down my window and ask if that stood for "extremely slow 96". :D

elwesso
02-19-03, 10:39 PM
Why didnt you, it would have been some punk kid anyway.

OPPORTUNITY MISSED!!

jadcock
02-19-03, 10:50 PM
Why not? I have a severe phobia with people doing something to my car. It's not a very big area here and I have a personalized tag also, so the car is easy to spot. If he got really pissed off, he could do damage to the car, so I try to never offend anyone. Sure, I could go back and press charges after damage was done, but I think it's a lot easier to never get in hot water to begin with. :p

elwesso
02-20-03, 05:13 PM
True dat

kcnewell
02-20-03, 05:35 PM
Or you could go stand on his windpipe till he coughs up the money for the repairs!......That's always fun!