Car Bucking @ low speeds Options

[elvasoshexai]

ok.. the celica is the first manual transmission car i've ever owned and drove for longer than 20minutes...

anyways.. a thread on another forum about someone's car (a corolla) bucking at low speeds/rpms in 2nd gear got me wondering...

my car does the same thing... and i always wondered if it was normal...

when i'm in 2nd gear and at a low speed or low rpm (below 2000) or when i just let go of the pas pedal quickly (like on my auto car), the car bucks 'a bit'...

i know 'a bit' is subjective.. but because ive never driven another manual.. it seems like 'a bit' to me... 100% it bucks more at low speeds (or when i release the gas pedal fast) than my auto cars...

so i was wondering if this was a problem because the other guy said his other manual car (some mazda) was really smooth in 2nd gear

somebody else said it's something to do with ignition coil.. but i dunno...

This post has been edited by elvasoshexai: Jun 16, 2006 - 12:20 AM

[expedition2166]

well some of the other gurus my correct me if im wrong but in most cases closed throttle and in gear rolling will cause a buck if the car is rolling faster then the rpm's provided by the engine the car rolls and puts a load on the engine and if the car moves faster there will be no load an automatic tranny has a series of planetary gear sets and over run clutches and thats why you feel no buck because a auto car free spins where as a manual car is a solid connetion between engine n wheels

[yyet]

I have the same problem, so when it "bucks" i just push the clutch in a catch it again to make it smooth. I really don't and couldn't figure out the problem.

Yet

[Kwanza26]

Because you're letting go of the gas at 2000 rpms...

[elvasoshexai]

Because you're letting go of the gas at 2000 rpms...

...o.. ur not supposed to let go?

[b1gr3d]

no. just let off a lil bit. or do like i do and throw it into neutral and coast(i've been told that i'm not supposed to do THAT either though so..)

[GTS13]

Yeah that bucking is normal, what you wanna look out for is the bucking while accelerating.

[DomGT]

I'm not a car mechanic, but here's my opinion. Just think of the physics of what your doing. Instead of giving your transmission the power of 2k RPM, your QUICKLY giving it the power of idle speed, about 700rpm. Your making is HARDER for the tranny to do its job, so it results in clunking.

If the problem persists, you may need to clean or replace your idle air control valve. When you let off the gas completely, the throttle body does NOT close completely. If it did, you car would turn off (no air going into engine). The idle air control valve, or IACV takes over when you let off the gas and keeps the throttle body open a little bit to keep the car running smoothly.

So from now on, pay attention to pure phsyics, and you'll go EASIER on your baby (car).

Oh one more thing, after driving my VR-4 for several months, I learned that the CAR itself has 1 or 2 ways it likes to be driven. Once you find that out, your golden.

This post has been edited by DomGT: Jun 17, 2006 - 3:02 PM

[toyotacrazy]

Check the rubber intake tube going into the throttle body. I bet its cracked. When you take off at low speeds the engine rears backwards spreading the snorkle tube open. Thus making the car run lean. Some duct tape is a quick band aid.

[CheesyLobster]

its bucking because you dont have experience driving a manuel car. when you become a better driver it wont "buck" anymore.

[elvasoshexai]

man.. when i took lessons on driving.. the instructor guy never said anything when i drove like this...

hm.. yea i guess i just need more experience n 2 find the way my car likes to be driven...

[JesterDC]

When my dad taught to drive his manual Celica he would tell me "ENGINE SPEED HAS TO MATCH ROADSPEED OR YOU'RE GOING TO PAY FOR MY NEW TRANSMISSION!!!" So if you're not sure about what RPM's you should be doing at a certain speed, go to a parking lot(an empty one) and do this thing I call catching the needle. It only works while in motion(downshifting or upshifting). First push in clutch and take foot off gas, shift 1-2, lightly touch throttle so the RPM's needle rises passing the numbers at about 1/sec., slowly let out clutch, when clutch is all the way out look at the tachometer whatever is on the tach is the engine speed relative to the roadspeed in your present gear.

After you've done that you'll really need to learn to drive by ear and feel. Really get to know your car's tendencies and keep your eyes on the road, not buried in your gauges or you'll never see that pool of quicksand that's so out of place in suburbia. Once I was finally riding smooth in my dad's converteble, I put the top up and my ear was telling me the engine was reving 2K less than it should be, I was wheel hopping so bad....