88 n/a vert.

clutch went out.
I was up on stands for like 2 months. While it was down, I installed a k&n 4" intake, koyo radiator, exedy clutch (kit)(did not machine flywheel) and removed airpump. i didn't un-install the egr (i think thats the acrynim) valve:

When I hit anywhere between 4k/4.5k rpm, it starts to shake, gear is irrelavent. It does it in neutral. I thought it was clutch chatter, and my buddy who works at a nissan performance shop up here in everett said "you put about 800 miles on it sence you got it running again? well it shouldn't be clutch chatter if it does it in neutral as well." so he said take off the vacuum line pertaining to the egr valve; no change. i also, just noticed that my wires that plug into my tranny are cut clean. I will fix that asap but i dont think thats it. do i need to take the egr valve out and put on the block-off plate (have in hand) for there to be change?

 

hey. what your sayin may help....

if its a hard shake of the whole car, mine was doing that as well around the same rpm, but my drive shaft was fucked up and nobody knew what it was until....SNAP! ! ! so check that out.

i may be WAY wrong. but just a thought.

 

I'm not sure - is there some reason you think it would be the EGR? All EGR does is lower combustion temps, and thereby NOx formation, by routing back inert exhaust gas to the intake under part throttle conditions. It sounds like you have a misfire; I'd be looking for unplugged vacuum lines or solenoids.

 

I really dont think its the driveshaft because it does it when im parked (in neutral). so lookin for vacuum lines eh?

 

Tranny mounts go bad from it sitting on stands all stretched out and disconnected? Motor mounts? Checked those?

 

well the tranny mounts are cool as far as i know. i checked them out when i took the tranny out. cleaned the mounts and everything and didn't see anything faulty.

 

Correctly sized counterweight from an auto?

 

i haven't changed anything as far as that is concerned, simply because it wasn't a problem in the first place. but im thinking it might be something to do with the ports. i dont know much about them... how many ports does the s4 na have?

 

6 ports. When did the problem start happening? Did it happen before you replaced the clutch?

 

it was after we did the clutch

 

Have you check the fan clutch or water pump? If the mounting bolts are loose or the pump shaft is worn that would cause a vibration. Does the engine have problem spinning above 5k?

 

sounds like something is out of balance. it could be the flywheel

 

Is the engine rough during the vibration, or is it purely something resonating? If it's a hesitation, putting on a cone filter will magnify how much you feel it.

Another thing to check is the ACV, if you removed the air pump, I would hope you removed the ACV or capped it somehow. If not, you've got a big potential exhaust leak (check valve is usually bad). I doubt this would cause vibration, but it doesn't hurt.

 

Lol wow, what is the acv? Is that what I thought was the EGR valve? lol. But now that you mention it, there is one of the nuts off the bolt pertaining to the fan/water pump I lost... I also put in a new waterpump. I forgot those details lol.

 

Why not have a friend rev the engine and hold it at 4-4.5 when the noise is beening made just go under the hood and try to find out where it is coming from. Can you rev all the way up?

ARE YOU POSITIVE you tightened everything when you put the new parts in. If I might ask is your car turboed?

Because there really is no reason to remove the air pump an a n/a.

 

Just to be clear...the engine shakes like it's off balance, or because it's not running smoothly?

Keep the clutch pedal in (clutch disengaged) and run in the RPM range you referred to. Do this in neutral and in gear - any difference in vibration?

 

It doesn't have anything to do with the ports. They only open under load and it depends on the load for when they open. Therefore, they wouldn't open in neutral.

 

I will try to have hockey do it. Yeah I have reved it up all the way when I first got it on the road. First thing I did was burnout (retard). Im pretty sure I tightened everything but I'll check over everything again before work. And no, its n/a

 

take off the K&N airfilter and try reving the car and see if it does it.

pfsantos said to rev the car with the clutch pedal pushed in and see if it does it.
If it does not do it then you have a transmission problem.

If it still does it
retrace your steps when you removed the transmission!
Maybe a ground isn't clean or it's looser
it could be anything! but it was prob caused by you

Did you remember to move the coolant temp switch in the bottom right side of the radiator to the new radiator?

a lot of stuff can cause a hesitation
don't go looking for problems that you don't have

Start by doing the things I said and then start looking at your sensors
use the online fsm(in the faq) and get a voltmeter. Start by making sure they are all plugged in and functioning properly (by doing the fsm tests).

goodluck

 

I was going to say driveshaft, but if it does it when in neutral I'd say mounts.
How many miles are on the car?

 

That radiator temp. switch is gone, I didn't swap it over because I broke the plastic part when I took it out. All the wires from the tranny were cut (clean... wtf?) I found one nut off the bolt that goes through the fan/waterpump pully.

I was told I dont need the switch, and I can drive fine without it. I dont know what its called and dont know where to get it. But its a 20 year old peice of plastic.

I also examined the nuts on the waterpump pully and some bolts are showing more thread than others, so what I'm going to do is get new nuts and torque them to the same spec. I wanna say ~ 25/35 inch lbs. So yeah, I think I know where to start now. If anyone comes up with anymore ideas they are GREATLEY appreciated. Thanks to all of you guys.

 

Are you sure the flywheel key was in place and didn't fall out. If the flywheel is mounted out of position it can cause an engine vibration.

 

well i wont be the sensor but it might be a good idea to get it fix because Temp is like 5-10% of your fuel control also 25-35 inlb sound real low i would think 25-35 Ftlb sounds more like it. but ya lupin is right. and have u check all your lines because a vac leak can cause it use a stefascop its like what docs use but with out the metal thing on the end and u can hear any leaks and if anything vibing

 

How are the plug wires? Could they be arching between each other? Rev the engine in the dark and see if you can see sparks between them.

 

The plug wires are new(ish). Some nice blue NGKs with the wire-protecting on them still. (I wanted them to fit in the little plastic mounts). Wont hurt to check though, they are kinda dirty it looks like.

The disk key way in place correctly, I spent my time with that making sure. Double checking, then checking again. So I think thats not it. Should anything change if I disengage the clutch (pushing in the clutch while car is in gear)?