If the coil passes those tests, the power transistor is suspect. The power transistor is what triggers the coil, much like points in an older vehicle. The Haynes manual has no information I can find on the power transistor, so I'm giving you the test procedure from the '89 FSM and I'm assuming the power transistors are the same. Check as follows:

The power transistor is the black, flat contraption mounted next to the coil on the coil bracket. Remove the 3-wire connector. As you look at the 3 electrical connections, mentally number them 1,2,3 from left to right.... they have letter designations on the topside of the unit, but my truck isn't here right now and I can't give you the designations that way - so -

With your test meter set on "ohms", check between terminal 2 (middle) and terminal 3 (right).... there should be no continuity (high reading in ohms).

Connect the negative (-) side of a 1.5v flashlight battery to terminal 2 (middle terminal) and the battery positive (+) to terminal 1 of the power transistor (you'll need some small alligator clips) - Now there should be continuity (zero ohms) between terminal 2 and terminal 3.

If you connect and remove the battery (+) lead, you should see the meter move back and forth between continuity and no continuity just like a switch - which is what the power transistor is acting as when voltage is applied.

This test is difficult to do because of the tight quarters, but be patient and get whatever clips you need to get good readings without the clips touching each other. If it's easier for you, remove the coil bracket so you can do the test on a table or workbench.

If the power transistor fails this test, you've likely found the culprit.

If the power transistor passes, remove and check the coil wire with your meter leads on each end - I don't have a handy reference on ohms/foot but guessing it should be somewhere around 2K ohms max for the short lead.

Let us know when you've tried these tests.

Oh, if either the coil or the power transistor fail the tests, I'd suggest getting a complete assembly from a junk yard as electrical components can last for 10 seconds or 100 years.

The power transistor has 3 contacts - labeled #1/#2/#3 from left to right. Connect the negative end of a 1.5v flashlight battery to terminal #2 on the power transistor. Connect the positive post of the flashlight battery to terminal #1. There should now be continuity between terminal #3 and terminal #2. When you remove the voltage from terminal #2 there should be no continuity between #2 and #3.

If the transistor doesn't perform in the prescribed manner, replace it.

No problem.

I'm in the middle of pulling my engine to make way for another and ran into a nightmare left by the transmission shop when they rebuilt the transmission..... stripped bellhousing threads, overtapped threads with SAE sizes, pulled thread-serts, over-torqued everything, missing transmission stay block bolt, loose transmission stay bolt.... you name it, they screwed it up - never seen such a Goober job. <img src="/forums/images/graemlins/barf.gif" alt="" /> <img src="/forums/images/graemlins/baby.gif" alt="" />

I didn't mean to sound testy, but I guess I needed someone to scold and you were convenient..... <img src="/forums/images/graemlins/lol.gif" alt="" />

Let us know if you need more help. <img src="/forums/images/graemlins/kewl.gif" alt="" />

Frank <img src="/forums/images/graemlins/cheers.gif" alt="" />