Toyota Supra 1990 Manual page 59

ENGINE MECHANICAL - Timing Belt
EM-27
EM0131
EM2909
EM2910
(e)
If there is noticeable wear on the belt teeth, check
the timing belt cover gasket for damage and correct
gasket installation. Check for foreign material on the
pulley teeth.
2. INSPECT IDLER PULLEY
3.
Check the turning smoothness of the timing belt idler pulley.
If necessary, replace the idler pulley.
INSPECT TENSION SPRING
Check the free length of the spring.
Free length: 69 mm (2.72
in.)
If not as specified, replace the spring.