Symptom: TBI has no injector pulse; distributor test Requires: Test Light with probe/clip. Unhook the 4 pin harness from the back of the distributor. Attach the clip of your test light to 12V Positive. Turn on the Ignition. Tap the purple/white wire on the 4 pin dist harness (IC Reference High) with the test light probe; it should create a test signal and fire the injectors. If this test is successful, reattach and try cranking. If still no injector pulse, check power feed to the distributor; if power feed is good, ignition module in distributor is bad.