NEED HELP, Nasty Vibrations!

dfordie

Registered User
I know this has been covered many times be4 but nothing similar to my problem, I have a 89 SC 5-speed all stock but the solid motor/trans mounts, now when i get in the car and start it she shakes and makes a rattling noise similar to metal on metal the stick shakes like a wh*#! And well so does the car, when the idle drops it smooths out but if reving in neutral or in gear it vibrates till the rpms drop (naturally) back down, now what puzzles me is that its happening out of gear, eliminating a drive shaft issue, i had one mechanic mention the throw out bearing and pilot bearing? But how... The trannys not engaged? The harmonic balancer seems to be running true so iv eliminated that? Could a tune-up be needed? It had a no start issue that was tracked.down to a bad maf/dis/cranksensor all wer replaced tho and motor smoothed out but that being said it was ran off 5cyl for a bit cause number 3cyl wasnt firing due to bad DIS. Any input would be appreciated! Im stumped boys n girls!
 
Quick question when vibrating in neutral is the vehicle stationary?


1. Check your firing order. The manuals are incorrect and these cars will run with an incorrect firing order. They run poorly but will run.

http://www.sccoa.com/forums/showthread.php?t=120621&highlight=Firing+order&page=2



2. What shape are your ignition wires and plugs in? If they are old I would recommend replacement. Especially if you. Had a Jo start condition where the plugs were probably getting fuel soaked.

3. I doubt if it is a throw out bearing, or anything drive train related if the car isn't moving when the harshness occurs.
 
This is when the car is parked, when i rev it as the rpms settle it makes a rattling noise and the shifter vibrates quite a bit. Iv checked the firing order and its correct they are the old plugs wires that were on the car when i baught it the spark plugs have been changed though to NGKs as far as the pilot/throw out bearing goes i was doubting that myself due to it happening sitting parked, i did get to take it for a boot tho and noticed if i kept it in gear and decelerated while in gear it did it more noticably and shook the car harder, dont know if thats a helpfull hint or not.
 
Vac at idle ranges from 16-18psi, im going to change my plugs and wires tnite and see if that changes things up, im still puzzeled as to the rattling sound if this is truely a spark & plug issue, anyone have any insight on that?
 
Dual Mass Flywheel

Just out of curiosity and lack of knowledge on my own part. Do they make a Dual-Mass flywheel for these vehicles?

The problem he is experiencing sounds just like a flywheel out of balance issue that has occurred on those dual-mass flywheels. I personally have seen this on trucks. The center bushing on the Dual mass unit wears out and causes vibration at idle. As you rev the engine it smooths out.
 
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