Here' the quick and easy chech for your ingnition switch
( from '89 vol 2 FSM , sec. 8 , page 152).
.
Disconnect terminal, black plug is the switch, white is hot.
Turn key to "on" position.
Insided black switch plug connect your ohm meter to the Black/white wire's terminal and to the black wire's terminal. These are ingnition connection inside the switch.
Also check B/W to Blue. This is accesory wire to fuse box and is also connected when switch is in on position.
I would use alligator clips so you can wiggle the key and wiggle the harness near the switch to check for a intermitant situation.
If your switch is bad it can be removed by taking out just one little screw on the bottom of the switch.
I got mine at NAPA.

Thanks LR! I agree...I think! What confuses me is the fact that I have control voltage going into the PT, yet nothing coming out of the coil secondary. I thought the pulsing control voltage (5v--open--5V--open...etc) was what made the coil set the spark in motion. If I'm getting pulsing 5V at the PT, and the PT is known good, shouldn't the coil be putting something out? I put a spark plug checker inline between the coil secondary and the dizzy center input and saw nothing. Confused. Is there a second event that occurs at the PT that could be absent and thus keeping the coil from doing its job?

Also, I have already swapped in Hazy's known good complete dizzy and am seeing no change. It (like the old one) passes all the troubleshooting tests. So there IS signal coming from the dizzy sensors, but the DASH TACH (and thus ECU?)is not seeing anything.

I'm going to go check the ignition switch per Dave's tip (Thanks Dave!). I'll report back.

So at this point it is looking like its either the ignition switch or a bad connector or wire somewhere between the dizzy sensors and the ecu. That sound reasonable? I think we've tested all the individual ignition components at this point.

Well...we haven't formally tested the Control Relay, though I visually inspected it (it was pristine inside) and I can hear it clicking when I turn the ignition.

Sorry for rambling. I'm recapping for my own benefit and also in hopes someone will see something in all that...

Thanks again. Off to the driveway.

You should be seeing a make and break of continuity with ground at the power transistor, not sure of which leads. If that doesn't happen, you will never see a spark. It's the breaking of the coil ground path that causes the spark.

Also do a coil function test. Apply 12v to one coil connector, and ground the other. Install a spark plug checker in the wire from coil to dizzy. Make and break the ground and see if you get a spark at the checker. If not, swap 12v+ and ground wire and try again.

Since you have a pulsing 5v signal at the PT, the ecu is good because it's sending the spark signal, and the ecu is getting power, or it wouldn't be sending the 5v signal. This leaves the coil and PT as failure points. Other minor possibilities are the dizzy cap, coil wire to dizzy, dizzy rotor.

Well, shoot. No 12v at the coil primary. I suspect the female connector right now. Could have been operator error, but I used my new piercing probe to pierce one of the wires going to that coil primary connector and, in order to make sure I had right wire pierced, I checked for continuity at the connector and could not get it. I might try chopping off the connector and connecting the wires directly and see if that works.

Gotta get these kids to bed.

Retested the coil. Its good.

OK, kids are asleep.

As stated, no 12v at the coil primary connector. That's either because I've got a bad connector (which would explain the manner in which she died--intermittent at first, then worsened till dead), or there is something further upstream keeping 12v from getting there?

To recap some more:

I have tested (or replaced with known working unit) the coil, PT, cap, rotor, dizzy (replaced whole thing), ECU, TPS.

Dave, I did your test as well on the ignition switch. It seems like its behaving normally. Since I did that kinda in a hurry (was getting rained on) let's leave that on the table as a possible cause.

So with the above eliminated, we are left with:

-Coil Primary Connector

-Some mystery section of wire or connector somewhere in the 12V line to the coil

-Ignition Switch

-Control Relay

-Satan herself

Oh great Guru's, can any of these items be ruled out based on what we know is working? Is there anything else I left off the list that I should be checking?

And back to that no-tach situation...where does that tach signal come from? I would assume the dizzy, but if that were the case then it should be getting signal.

If the ECU is giving the 5v signal voltage, then the ECU is completely happy then, correct? But then why is it not firing the injectors?

I feel like we are close! - <img src="/forums/images/graemlins/cheers.gif" alt="" />

UR ECU aint seein' the motor spinnin.

Yes, it is. The PT is getting a 5v pulsing signal, so the ecu is seeing the dizzy crank position sensor signal.

1. Hook 12v+ straight from the battery to the coil + wire via a straight pin stuck thru the wire and see if you get spark. This will eliminate the coil connector as a cause.

2. Test the output at the other end of the coil + wire. This is in a strange place on my 89fsm, look for an 8 pole connector on the pside fenderwell, coil+ power is a 2BW wire in position 2, and the tach signal wire is a .85 WB/L wire in position 6. With the catch at the top, number 1-4 is on the top, and 5-8 on the bottom.

3. The coil power comes from the 3BW at the ignition switch, which should have 12v+ in both start and run. Power in to the ign sw is a 3W wire. Check it for 12v+, too.

I think we are getting close now...

Excited. Its time this Monty got back on the road.

Gotta wait till kids settle in, then I might just head out to the driveway. If not, ill be up at 5am to test b4 work.

*UPDATE*

Well she is alive! My friend and I spent a Saturday experimenting and staring at the wiring diagrams. In a last ditch hail Mary we ran 2 wires from battery--one to the fuel pump check terminal and one to the ignition coil connector. Bless her tough heart she fired right up on the first try after sitting for over a year. Seems that while proper voltage was present and measurable at these 2 points, the connection must not have been sound, which maybe didn't allow enough current to pass to make the stuff work.

So anyway, we are not quite there, as I still haven't figured out exactly what is going on. But at least I have a workaround, and maybe one of the guru's here can use this info to zero in on it. Both wires must be connected for it to run. I have to, not surprisingly, disconnect them to stop the engine as well.

Thanks everyone for all your help with this. We are close!