Mystery Vibration, need ideas
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From: Hockeytown, MI
Mystery Vibration, need ideas
g3 integra gs ~100k miles, built turbo b18c5.
What feels like driveline vibration occurs only under high load, from about 3k rpm up. The engine was recently rebuilt, but the vibration started before that. Crank journals all looked fine at time of rebuild. New motor now has 1500 miles. Plugs look fine, compression test good. Motors mounts are all newer aftermarket and look fine.
-The vibration usually happens all the time, but rarely it doesn't do it right away when coming from a cold start. Yesterday it ran fine for 30 miles on the highway (plenty of full load high gear pulls where its usually at its worst) and then popped up when we got off the highway. It doesn't seem to be combustion related, since the torque doesn't really drop off, just an increased vibration.
-It seems to be engine speed dependent rather than vehicle speed (frequency of vibration increases proportionally to RPM)
-All tranny bearings looked great. A known good tranny was swapped in anyway, and it was still there.
-Also swapped/replaced:
Transmission
Wheel bearings
LBJ's
axles (two diff pairs)
intermediate shaft
-Only rotating parts left that hasn't been tried is the engine itself, brakes, and wheels/tires.
-This car has corvette breaks redrilled for 4 lug, with twin piston Baer calipers in front.
Running out of ideas here. The only thing we can think of left to try is to disconnect alternator and p/s, and replace crank pulley (all stock).
What feels like driveline vibration occurs only under high load, from about 3k rpm up. The engine was recently rebuilt, but the vibration started before that. Crank journals all looked fine at time of rebuild. New motor now has 1500 miles. Plugs look fine, compression test good. Motors mounts are all newer aftermarket and look fine.
-The vibration usually happens all the time, but rarely it doesn't do it right away when coming from a cold start. Yesterday it ran fine for 30 miles on the highway (plenty of full load high gear pulls where its usually at its worst) and then popped up when we got off the highway. It doesn't seem to be combustion related, since the torque doesn't really drop off, just an increased vibration.
-It seems to be engine speed dependent rather than vehicle speed (frequency of vibration increases proportionally to RPM)
-All tranny bearings looked great. A known good tranny was swapped in anyway, and it was still there.
-Also swapped/replaced:
Transmission
Wheel bearings
LBJ's
axles (two diff pairs)
intermediate shaft
-Only rotating parts left that hasn't been tried is the engine itself, brakes, and wheels/tires.
-This car has corvette breaks redrilled for 4 lug, with twin piston Baer calipers in front.
Running out of ideas here. The only thing we can think of left to try is to disconnect alternator and p/s, and replace crank pulley (all stock).
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Joined: Feb 2005
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From: Ohio
Re: Mystery Vibration, need ideas (sackdz)
have you tried raising the wheels in the air and checking the vibration? what about the harmonic balancer? is it ok? if you suspect the rotors, just remove them and run it, to see if the vibration is gone....just remember to shut the car off and NOT touch the brake pedal, ...maybe even put some wood in the caliper, just in case you hit the brakes out of reaction
Thread Starter
Honda-Tech Member
Joined: Jan 2000
Posts: 8,062
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From: Hockeytown, MI
Re: Mystery Vibration, need ideas (srmofo)
No, haven't tried that.. but I'm not sure it would work because it only happens under high load, and you cant get high load with the wheels in the air.
I think we are going to try replaceing all suspension bushings with poly to see if it is a weird suspension resonance or something.
[e] I guess you could get a good amount of load in the air if you dragged the brakes at the same time
I think we are going to try replaceing all suspension bushings with poly to see if it is a weird suspension resonance or something.
[e] I guess you could get a good amount of load in the air if you dragged the brakes at the same time
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