Tell you fella's what.

[jfunez]

hey supramacist......you mention there is a ground on the starter....well. ther is not supposed to be one.

1.st.....there should be only two wires going to the starter, a big one and a small one.

the big one feeds a constant battery power to the starter, the litle one comes from the ignition switch and is only a battery signalm that comes on only when the ignition is turned to crank and you have your clutch fully pushed down...
easy way to check for this is to get a test light and check for constant power at the big wire....if it does then check power on the small wire when someone tryies to start the supra....it should come on, and go off as soon as they let off the key.

By the way.. the starter grounds it self through the bell housing or the motor,so make sure you have all grounds to the tranny and the motor fullly secured and that the starter is securelly fitted to the tranny.
good luck.......oh.....and check and see if you didnt brake that knock sensor behind the starter....it very easy to do when tightening the top starter bolt.... good luck