Internal engine vibration
New User
Joined: Jan 2000
Posts: 14
Likes: 0
Internal engine vibration
I have a 1989 4.9 liter six which vibrates realy bad between 2020 rpm and 2200 rpm. Its seems very smooth below and above this rpm. I'm racking my brain to figure it out. Harmonic dampener??
New User
Joined: Jan 2000
Posts: 14
Likes: 0
Internal engine vibration
At first I thought it was in the drive train but in diagnosing the problem I found I got the vibration in neutral. I removed the serpentine belt just to eliminate the driven accesorys and it made no difference. I'm starting to suspect the exhaust system , manafold,down pipes (they're split) and collector. They vibrate pretty bad but I thought it was the engine shaking the exhaust but it may be just sympathetic vibration (something that vibrate along with something else at just the right frequency).
Elder User
Joined: Feb 2002
Posts: 504
Likes: 2
From: Saddle Brook United State
Internal engine vibration
Hi 
I had a vibration like that in an 89 van with the 300. It turned out to be the baffels in the original muffler vibrating. My 90 pickup does the same thing only very slightly it also has the original muffler.
Bob/ stractor
I had a vibration like that in an 89 van with the 300. It turned out to be the baffels in the original muffler vibrating. My 90 pickup does the same thing only very slightly it also has the original muffler.
Bob/ stractor
