clutch disengagement at high speed under acceleration (yeah i searched dangit)

[Tsukiko]

I just recently started driving my 90 s13 around and am having some clutch (possibly transmission) issues. keep in mind the clutch is bone stock, as is the rest of the car.

let me start at the beginning.

I was fairly happy with the clutch when i started driving the car initially. nothing major, clutch felt a bit spongy though, not the smoothest engagement in the lower gears. then one day the upper radiator hose busted, and naturally i replaced it. In the process of doing so, i figured out where that random wire harness that had been flopping around my engine bay was supposed to be.so i plugged it back in.

and then the clutch changed dramatically. the pedal itself sunk down a few good inches, and when i went to disengage the clutch i absolutely had to bring the pedal all the way down. it seemed like there was no slack in the pedal travel at all ( the clutch was either all the way down and disengaged or a half inch or so and in the friction zone), and engagement smoothed out. not only that, but the car gained some acceleration ability as well. all in all i was thrilled. but then when the motor heated up the effects started to slack very slightly. So i jiggled the wire harness a bit, gave it a good shove to make sure it was solid, waited for the motor to cool down, and bingo. back to the amazingly solid clutch that i didnt have to push the pedal a mile to operate. its been a few days and ive become sick of popping the hood every so often and pushing that harness back in, since its kindof under the intake manifold. not such a big deal though, until;

more recently the clutch has been disengaging at high speeds, usually over 70mph when im accelerating up hill. startling at first but one pump of the pedal and you're back in business. until you try to accelerate up hill again past about 70mph.

I asked some friends, and searched the forums for info, and learned that since the clutch disengages without issues i do not need to bleed the hydraulic system. I have however ordered a slave cylinder in hopes that it would solve my problems. Today a friend told me it could also be my throwout bearing, which is a bigger swap than i am capable with my limited knowledge and toolkit.

anyone have any input?

[FRoSt415]

hows the Clucth Master Cylinder? fluid level. start from the easy things then work down. any leaks in CMC? do you have any play with your clucth before it engages? let me know what happens after you install ur slave clyinder.

[Tsukiko]

will do. itll be a couple days before it gets here. thanks for the help. i have checked the master cylinder level, and its full.

[EviL inside]

your clutch is slipping. time for a new clutch disk.

bleed the clutch hydraulics. mine somehow got air in it just from sitting, so it's easy to get air in it.

[Tsukiko]

i seriously doubt that its simply the cluctch disc slipping. i can still launch in first at whatever rpm i want and then squeel the tire (damn open diff) pretty hard into 2nd.

[EviL inside]

mine is slipping too, i got grease on it during install.

i can spin BOTH tires through first and second, but on the interstate, if i gas it doing 70+ it slips.

it can happen,,,it takes a lot of power to accelerate at 70+ because of wind drag.

it's slipping.

[LooseSlide]

it is most likely the clutch, put the car in 4th at 25 and floor it, it should slip. you could also have some oil leakege getting on the clutch, that could also cause it to slip.

the harness is most likely a coincidence as there aren't any electronics in the hydraulic clutch system on our cars, w/ the exception of the clutch switch. but that just lets you start the car and disengages the cruise control when you press in the clutch pedal so you dont over-rev the engine.

hope that helps some and GL

[Tsukiko]

thanks. i guess once i go to replace the slave cylinder ill try to see if there are any leaks in or around the trans. hell the clutch is probably original with all 126k mi. on it.

at this point im probably going to replace the clutch, throwout bearing, etc. asap.