i have a 1990 2+2 N/A 300zx which is in good condition only problem is that it vibrates and im not to sure whats causing it and dont want to throw more money at it when it doesn't get fixed! its just annoying driving and hearing a vvvvvvvvvvvv especially when i accelerate. i recently brought it into a mechanic to get the carrier bearing changed and gearbox oil and diff oil changed but its still vibrating. it does not vibrate in idle. if i rev the car in neutral it vibrates and is at its worse at 2000 revs. same when im going down a hill in neutral it still vibrates. i have put new tires on and had them all balanced so that is not the cause. the mechanic wasn't that helpful other than saying that maybe i should get the drive shaft balanced. im wanting to know if anyone else has had this problem b4 and could let me know what was causing it as it is really starting to irritate me. cheers for guys. ill need all the help i can get.
if i remember correctly ive recently read something like this on the forum who had a similar problem. i think it was their engine mounts or transmission mounts im not sure...hopefully somebody else with way better knowledge will be able to help...good luck
I too remember seeing this not long ago, thought it was an electrical thing... Perhaps PTU if series 1?
Revving the car in neutral while stationary and still having a vibration means that problem is not the tailshaft, so you need to be looking at engine or transmission mounts. Rolling down the hill in neutral (I assume revs at idle) and having a vibration points more to the transmission mount. Look here for comparison of old & new mount. Easy to pull out the old mount and have a look at it before chasing elsewhere. To be on the safe side check that the bolts holding the gearbox to the engine have not come loose.
thanks guys its not that too expensive to fix ill look into it further. any more help would be appreciated.
i had the same problem, my car would vibrate REALLY bad at about 2500 rpm stationary or moving didnt matter, it kept the vibration through all revs just worse at 2500. I too thought it couldnt be electrical so i did wheel balancing and things like that, in the end it was the s1 PTU. I suggest getting an s2, mind you it will still vibrate with the s2 unless you clear the ECU codes!
how do i know if i have the s1 ptu? also where would i get an s2 ptu? and im just wondering why would the ptu cause my car to vibrate?
A faulty PTU can cause the engine to miss and subsequently rock it from side to side a bit. But wouldnt that be an obvious issue? I'd be more inclined to replace the transmission mount (Based on whats mentioned prior). It's a cheap enough replacment part that ought to be done for preventative maintenace reasons anyway. The Trans mount sags overtime (this problem not really visually noticeable untill removed/compared with new). The sagging causes the tail shaft to be out of a slight alignment and a vibration would certainly be felt as the engine revs due to trans mount excessive flex/movement.
i might as well replace the engine mounts as well. btw how many engine mounts and transmission mounts do i need?
Because the PTU controls the spark if its faulty then it will misfire causing a vibrating feeling on every revolution as it misses firing on that cylinder. Remember after you replace the ptu, clear your ecu codes.
Such can be sourced here: http://www.conceptzperformance.com you'll want 1x Stock trans mount: either manual/Auto differ or alternativly a Nismo trans mount which is cheaper (I have a Nismo type in one of my Zeds without any issue. ie despite what others perceive/post in forums) 2x motor mounts are required: http://www.conceptzperformance.com/Cart/description.php?II=601&Car_Type=NIS300&UID=
Oh, I see from your profile you're in New Zealand! Look me up on www.300zx.co.nz or email nay300@gmail.com. http://www.300zx.co.nz/phpBB2/viewtopic.php?t=5843 I import regulary from conceptz USA which seems to be the cheaper source for Zed parts. I'm conducting a club bulk buy this month through the 300zx.co.nz forum, and could perhaps save you $$ by piggyback shipping.
Hmm I have the same problem with the vibration around 2500 rpm. Seems like it's caused by a slight miss. I have changed my ptu from a s1 to a s2. Still have the same problem. What is the fault code?
To clear/reset the ECU you'll need to disconnect the battery and wait awhile - or drain the excess electricity (dormant) by keeping your foot on the brake pedal to discharge it through the brake lights. Once thats done reconnect battery and ECU should hopefully play ball.
