Vibration @ ~2500-3k rpms
07-20-2015, 10:15 AM
#1
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Join Date: Feb 2003
Location: Cocoa, FL
Posts: 437
Vibration @ ~2500-3k rpms
I have a 94Z that I've recently got running after having sat for several years. Time and money prevented me from getting her going a long time ago, but I finally got around to replacing the opti...which had been the culprit all along.
After reassembling everything, she seem to run fantastic. However, after getting her on the road I noticed that she is slightly under-powered and had a vibration that arose around 2500rpms and would continue until about 3k rpms, to which it would begin to smooth out. I pulled the car back into the driveway and revved the engine whilst being stationary so I could rule out a drivetrain issue, and the vibration was still present. So I know it is a motor issue, but it something that I've never experienced before.
I was thinking that it might be a balancing issue... So my question is basically whether it was possible or not to put the hub/balancer on improperly? What other causes could there be for this vibration and a slight lack of power?
Thanks in advance for the help!
After reassembling everything, she seem to run fantastic. However, after getting her on the road I noticed that she is slightly under-powered and had a vibration that arose around 2500rpms and would continue until about 3k rpms, to which it would begin to smooth out. I pulled the car back into the driveway and revved the engine whilst being stationary so I could rule out a drivetrain issue, and the vibration was still present. So I know it is a motor issue, but it something that I've never experienced before.
I was thinking that it might be a balancing issue... So my question is basically whether it was possible or not to put the hub/balancer on improperly? What other causes could there be for this vibration and a slight lack of power?
Thanks in advance for the help!
07-20-2015, 10:44 AM
#2
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Join Date: Sep 2000
Location: Stillwater Ok USA
Posts: 574
Re: Vibration @ ~2500-3k rpms
Did you use the correct puller? The only thing I can think of it that you may of damaged it. Did you get it fully seated upon reinstall?
Slight lack of power...hmmm. Maybe the vibration is being mistaken as misfire. Check that you got all the plug wires back correctly. Possible the opti was indexed wrong.
Slight lack of power...hmmm. Maybe the vibration is being mistaken as misfire. Check that you got all the plug wires back correctly. Possible the opti was indexed wrong.
07-20-2015, 11:13 AM
#3
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Join Date: Nov 1998
Location: Hell was full so they sent me to NJ
Posts: 70,646
Re: Vibration @ ~2500-3k rpms
It's a harmonic damper, not a balancer. Exact position on the crankshaft should not be critical. If you replaced the Opti, all you needed to do was separate the damper from the hub. No need to pull the hub. When you bolt the damper back on the hub, the arms on the hub are not evenly spaced, so the damper can only bolt back on in the correct position. If you did pull the hub, exact position should not affect balance. That's why GM didn't spend 5-cents on a key.
Listen to DelSoto.... check the damper for a damaged hard rubber ring that holds the inner and outer (pulley) portions of the damper together, and provide the dampening capability.
Listen to DelSoto.... check the damper for a damaged hard rubber ring that holds the inner and outer (pulley) portions of the damper together, and provide the dampening capability.
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