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?

[stillracing]

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?

By disengage do you mean pop's out of gear, or just slips to all hell, or maybe just bypasses the slipping and goes straight into neutral(like, because its a stick) with it in gear still ?

I had an issue with a car popping out of gear under deceleration once before... but that was due to missing shims in the transmission from the shop. Let me know, and I'll try to help.

STiLL RACiNG

[Tsukiko]

it just gives way, transmission in gear. the rpms drop and the car noticably decelerates. all i do is pump the clutch once and its back. thanks for your help!

[stillracing]

it just gives way, transmission in gear. the rpms drop and the car noticably decelerates. all i do is pump the clutch once and its back. thanks for your help!

That's FuNkY!?!? so it was fine UNTIL you plugged in a plug near the intake manifold...strange...

It sounds like your pressure plate is busted maybe the springs in it... hard acceleration uphill past 70 and it messes up...

No clue as what you plugged back in, but if it gave you more acceleration then ...that's more power...and it maybe just enough to outdo the old weak clutch at a high resistance rate (uphill in high gear past 70)...It may be your clutch disc being worn too.

Now from your description it isn't slipping..but just dropping rpms all of a sudden while in gear....

When it drops rpm's is it slowing down just as if you had lifted your foot from the gas pedal..simple deceleration from engine compression? Or is it more of a rpm drop than it should be due to the speed of the car?

I'll give it more thought and hopefully I can help... Sounds like a ***** of a problem though...

[Tsukiko]

my clutch slave cylinder just got here, so ill have to swap it asap and see if that does anything.

unfortunately i dont have the tools, time or patience to get the car off the ground and get at the clutch assembly.

[stillracing]

my clutch slave cylinder just got here, so ill have to swap it asap and see if that does anything.

unfortunately i dont have the tools, time or patience to get the car off the ground and get at the clutch assembly.

It really isn't THAT bad or hard to do but if so I'd have at least 2 jack stands and maybe 2 jacks as well...but then it should be ok and safe. =)

Let me know if the slave cyl. swap works.

[stillracing]

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.

Can you take a pic of the plug you put back in? send it to my email address if you can't host it somewhere to show it on here.

Lataz

[Tsukiko]

yeah ill send it asap.