IMPORTANT: A component that is out of balance will NEVER cause higher than a first order vibration.
1.5 Order Engine Speed Related Vibrations are normal on three cylinder engines. Although these vibrations are normal, they should not be heard or felt in the passenger compartment.
Notice: Some engine speed related vibrations are normal; however, they should not be felt in the passenger compartment. Click here to see which vibrations are normal.
On engines that have a normal 1.5 order vibration, the following components, if defective or misadjusted, can allow the vibrations to be transferred into the passenger compartment.
Check for grounded out or damaged mounts. This can be done easily by watching the vibration amplitude difference on each side of a mount with the EVA. Place the EVA's sensor on each side of the mount. The amplitude will be higher on the engine side of the mount and lower, if not totally gone, on the frame side of the mount.
Check for grounded out mounts, mounts filled with dirt, or damaged mounts. This can be done easily by watching the vibration amplitude difference on each side of a mount with the EVA. Place the EVA's sensor on each side of the mount. The amplitude will be higher on the transmission side of the mount and lower, if not totally gone, on the frame side of the mount.
Check for grounded out exhaust pipes, rubber mounts that have been replaced with solid mounts, and spring-loaded bolts on flexible exhaust couplings that have been replaced with solid bolts. This can be done easily by watching the vibration amplitude difference on each side of a mount with the EVA. Place the EVA's sensor on each side of the mount. The amplitude will be higher on the exhaust pipe side of the mount and lower, if not totally gone, on the frame side of the mount.
Check for collapsed, grounded out, or damaged mounts. This can be done easily by watching the vibration amplitude difference on each side of a mount with the EVA. Place the EVA's sensor on each side of the mount. The amplitude will be higher on the frame side of the mount and lower, if not totally gone, on the body side of the mount.
If the vehicle has a two-piece or three-piece propshaft, check to see if the front piece of the propshaft has a slip yoke which has been inserted too far into the transmission or transfer case (see image on the lower left). If so, the lack of slip-joint movement can cause a binding in the powertrain mounting allowing normal engine vibrations to be transferred into the passenger compartment. loosen the center propshaft support bearing and slide the propshaft rearward to allow for some slip joint movement (see image on the lower right).
Make sure no hose contact the bulkhead or inner fenders where it should not contact.
Check to see if the mounts for the running boards are bypassing the body mounts (see if the running board mounts to both the body and the frame). Disconnect the mounts to eliminate the running boards as a possible cause of the vibration concern.
Check to see if items like the throttle cable, wiring harnesses, fuel lines, brake lines, transmission dipstick, transmission cooler lines, etc. are making contact with the powertrain (engine and transmission) and the frame or body.
This page was last modified Thursday, March 05, 2009 09:02:44 PM
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