2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Strange Vibes man... (around 5k RPM)

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Old Nov 21, 2008 | 08:10 AM
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TX Strange Vibes man... (around 5k RPM)

OK, so, got my project 7 (86 N/A sport model) from my dad's driveway. (Had been parked there for about a month waiting on my new garage.) Fire it up (always fires up on the first try, love that) and warm it up. Started the 15 mile trek from his house to my garage... When I got onto the highway I began to notice some vibrations after 4k RPM. (also above 45mph). This is a new symptom for this car, had not done this before. Almost felt "harmonic" had a pattern to the vibration, so I wonder if anyone has an idea on this...

Lemme know
DallasFC1
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Old Nov 21, 2008 | 08:56 AM
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From: And the horse he rode in on...
Originally Posted by DallasFC1
OK, so, got my project 7 (86 N/A sport model) from my dad's driveway. (Had been parked there for about a month waiting on my new garage.) Fire it up (always fires up on the first try, love that) and warm it up. Started the 15 mile trek from his house to my garage... When I got onto the highway I began to notice some vibrations after 4k RPM. (also above 45mph). This is a new symptom for this car, had not done this before. Almost felt "harmonic" had a pattern to the vibration, so I wonder if anyone has an idea on this...

Lemme know
DallasFC1
Maybe flat spots on the tires after parking it for a month? Try driving it on the highway for 50 or so miles. The tires will get completely warm and if there are any flat spots, they will work out.

Just my best guess.
Good Luck!
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Old Nov 21, 2008 | 10:32 AM
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i know that when the oil is getting low in my engine the engine makes a "harmonic" vibrating sound. So then i simply top off the oil and its gone for a while
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Old Nov 21, 2008 | 10:39 AM
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Originally Posted by jfpimp91elkland
i know that when the oil is getting low in my engine the engine makes a "harmonic" vibrating sound. So then i simply top off the oil and its gone for a while
WHAT?!

You are SERIOUSLY damaging your engine if this is the case. If your oil level is so low that it effects how the engine is operating, it is well below the safe point.

To the original poster, you need to isolate whether the vibration is caused by the engine or drivetrain. With the car stationary, hold the engine at 5K RPM. Does it vibrate?
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Old Nov 21, 2008 | 11:14 AM
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it vibrates when the oil is only like 1/4th down from full. in other words 3/4ths full.
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Old Nov 21, 2008 | 12:10 PM
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dipsticks only read one quart

Check what aaron said and if it is the tires then try to do a big burnout, may not help if it's the front though
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Old Nov 21, 2008 | 02:05 PM
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yea i know the dipsticks read 1 quart. It vibrates between 1/4th of a quart low and any thing less. What could cause this type of vibrating?
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Old Nov 21, 2008 | 08:00 PM
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the wheels coul also be seriiously out of balance. does the steering wheel shimmy bak and forth? maybe a wheel bearing is going bad, or your wheel is riding on the tread weird due to an alignment issue... does your car pull straight when you let go of the wheel?
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Old Nov 21, 2008 | 08:05 PM
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yea all my stuff is fine. car pulls straight.
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Old Nov 21, 2008 | 08:26 PM
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did it vibrate while parked, like aaron suggested?
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Old Nov 22, 2008 | 09:47 AM
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yea mine does
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Old Nov 22, 2008 | 10:52 AM
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If it vibrates when parked and the oil is low, the engine is being starved. I doubt this is the problem with the original poster.
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