Rpm goes crazy after clutch replacement
 

It looks like you crankshaft sensor is bad. get the engine code. This usually helps a lot for diagnostic. If you replace the flywheel ? it could be misaligned.

Yep, what fflipski said. If all you did was the clutch the most likely suspect is the crank sensor. Either the sensor was damaged while re-installing the trans or the flywheel is miss-aligned.
-Icer

How would someone damage crank posiition sensor
 

Just curious as i am doing clutch myself soon,how does someone damage the crank position sensor when doing this?

Hi Painterguy,

The crank position sensor bolts up to the engine block right where the trans mates to it, the bell housing actually has a relief cut in it for the sensor. I believe it's an electromagnetic position sensor encased in plastic. There's magnets or steel plates on the outer perimeter of the flywheel that it reads to index the location of the crank. Long story short, if you forget to remove the sensor before dropping or re-installing the trans, there's a high probability that you will damage or "crush" the sensor during the wiggling and shoving process of aligning the trans input shaft/spline with the clutch & pilot bearing. It's just a single 10mm bolt holding the sensor in. Super quick and easy to just remove it and tuck it up over the clutch hydraulic lines so it stays safely out of the way.

Since you're also doing a clutch, I'm guessing you may also change the flywheel? If so, be mindful of the alignment peg on the back of the crank. You MUST make sure your flywheel is properly aligned with this peg. Most aftermarket flywheels will have a machined hole that matches with this peg... which *should* make it impossible to mess up, but somehow people still make mistakes, I suspect because there are multiple alignment holes drilled on their particular choice of flywheel. If you look closely though, the hole should be obvious/unique, if not then you need to check out the instructions provided with the product. I've uploaded a photo of the Specialty Z flywheel I run with as a reference/example.

Pictures speak a thousand words so...

https://cimg6.ibsrv.net/gimg/my350z....111025708e.jpg

https://cimg8.ibsrv.net/gimg/my350z....ed4d0a9092.png

Thank you Icer..much appreciated!

I have an HR,appears mine is located up top,around the 2 o'clock position.I removed the transmission without disturbing it,do you really think i should remove it before i re-install?Don't want to fudge it up.

Hi Painter,

I'm not as familiar with the HR, however that said, if you can easily remove & re-install the sensor while the transmission is in place, I would. It's just not worth the risk considering the small time investment needed. Otherwise, if it's a real pain to get hand tool access to the 10mm bolt holding in the sensor, I suppose you can try risking it, but you would need to go slow and have confident control over the transmission as you guide it in. These 6 speed transmissions are heavy! To assist with guiding mine into place, I made a 3/4" plywood board utilizing pre-existing bolts on the bottom of the trans to help steady it against the crappy transmission jack I was using. Seriously I spent a stupid amount of time struggling with that jack trying to get a clean shot (crappy harbor freight one I borrowed from a friend, it was seriously messed up). After spending the 30min or so making the plank/board, I had the transmission mounted up almost immediately!
-Icer

For your viewing pleasure...

https://cimg7.ibsrv.net/gimg/my350z....16b268f713.jpg