Please tell me its not the transmission

[ZER0COMP]

s13 sr20det redtop. (1989 240sx)... Just got the motor running about 48hrs ago.. all of a sudden car starts idoling high and takes off on its own when in gear the only way i can make the rpms go down at a light or stop sign is to play with the break and clutch. I can change gears 1st-5th but when ever i push the clutch in the rpms go up in stead of down... Please tell me its not the transmission... also if it helps I added a nismo knock off short shifter like 3 days ago before i even started the swap

[bone_stock_240]

It does not sound like the transmission. It seems that you are idling super high for some reason. Pressing on the brake will drop the idle a bit because the brake booster uses vacuum pressure. Maybe describe a bit more what problems you are experiencing because I don't really understand what you are talking about when you say the car takes off when in gear.

[ZER0COMP]

like if i put the car in 1st gear and let off the clutch, because the rpm's are high anyway with out giving it gas the car will set itself in motion, and sometimes ill cheat the rpms by putting it in 4th gear one im already in motion just to keep the rpms down. i remember when my transmission went out on my mirage(mitsubishi) i could not shift it at all, but like i said on the 240 all gears are working. could the problem be the shift linkage if the short shifter is not pulling the transmission fully out of the last gear i was in??

[bone_stock_240]

Try adjusting your idle before you go messing with transmission stuff. Idle is easy to adjust. What does your car idle at in neutral, and what does it idle at with your foot on the clutch?

[ZER0COMP]

Once i get the Tach working ill be able to check that... while i was at lunch i checked the engine and noticed i had antifreeze leak in 2 places on the same line( upper right Hose) and the resivoir was empty, I feeled the the resivoir and added some to the radiator. and the problem stopped. does the coolent have anything to do with the rpm, and what could me turning my coolent dirty and brown or even orange...
Modified by ZER0COMP at 11:52 AM 4/11/2007

[bone_stock_240]

I am not sure, you will have to wait for someone with more experience in this. Check your oil when the car is warmed up and make sure that it does not look like a chocolate milk shake. If that is the case, it might be a blown headgasket.

[DevilMB3017]

My car did something similar after I replaced my brake master cyl. Got confused for about an hour, and then noticed my throttle cable wasn't in the little clip and it was all over the place.

Check your throttle cable and throttle body that it plugs into...

Oh, btw, the reason for your RPM to go up when you push the clutch is that your cutting the load on the engine.

[ZER0COMP]

well its not doing it anymore but it was reving high without the clutch being pushed in as well... like i said I just finished the swap and turned the motor over about 48 hours, and day 2 has been pretty rough. just an hour ago transmission slipped out of gear and couldn't get it back in with out grinding it back in. Found 2 coolant leaks. gear oil pooling around the short shifter etc... Don't worry about answering any of the above. this is the first swap i'm actually doing with my own 2 hands, so im trying not to blow up the forums with easy to research answers (it's just that the high reving thing scared me) and i must say its amazing the different feeling between some else doing the swap for you ( my honda prelude) and doing the swap yourself ( SR20det )

sorry i guess im tooting my own horn a little bit

Thanks for the help and advice