No power at coil when cranking..Why??

[78-911SC]

I have 12v @ the coil in the run position but when I'm turning over the engine I have no volts or pulses at the coil?? That's the problem. So how did I get here? A number of years ago I put a 3.2 into a 70T. Did all the modification including replacing the reference and speed sensors and ran it for a month or so before*pulling everything out of the car including all wiring. Now I have everything back in the car and trying to start it.
Here is what I know.
Coil has a spark on the bench with current coil wire and 12v in the run position.
ECM pins 18 and 35 have 12v volts with ignition on.
Fuel pump is working and there is fuel to the rails. Pin 20 runs pump when grounded.
All the grounds in the ECM have continuity.5,10,16,17,19. All body grounds ok.
Reference and speed sensors are new and ran when last in the car. Both have 1.062 ohms at pins 8/27 and 25/26
Tried a second ECM with no luck.
New battery and starter which is very strong.
Relay at the ECM has been checked and jumped just to be sure.
Here is what I don't know. A lot!
Why am I not getting intermittent 12v when cranking and have 12v prior to cranking? I'm pretty sure this is why it's not starting. No spark when cranking.
Is it possible that my ignition switch has something going on? Checked wiring and looks ok by way of the wiring schematics.
How would I check the ignition?
Any thoughts or ideas would be appreciated.

[mysocal911]

Originally Posted by 78-911SC

I have 12v @ the coil in the run position but when I'm turning over the engine I have no volts or pulses at the coil?? That's the problem. So how did I get here? A number of years ago I put a 3.2 into a 70T. Did all the modification including replacing the reference and speed sensors and ran it for a month or so before*pulling everything out of the car including all wiring. Now I have everything back in the car and trying to start it.
Here is what I know.
Coil has a spark on the bench with current coil wire and 12v in the run position.
ECM pins 18 and 35 have 12v volts with ignition on.
Fuel pump is working and there is fuel to the rails. Pin 20 runs pump when grounded.
All the grounds in the ECM have continuity.5,10,16,17,19. All body grounds ok.
Reference and speed sensors are new and ran when last in the car. Both have 1.062 ohms at pins 8/27 and 25/26
Tried a second ECM with no luck.
New battery and starter which is very strong.
Relay at the ECM has been checked and jumped just to be sure.
Here is what I don't know. A lot!
Why am I not getting intermittent 12v when cranking and have 12v prior to cranking? I'm pretty sure this is why it's not starting. No spark when cranking.
Is it possible that my ignition switch has something going on? Checked wiring and looks ok by way of the wiring schematics.
How would I check the ignition?
Any thoughts or ideas would be appreciated.

Then the ignition switch in the crank position is NOT supplying 12V to coil.

[Chris78]

Id double check the wiring at the ignition switch

[Flat6pac]

The coil wire needs to be tapped into emergency light system so there is power coming to the coil in the crank position. Lots of the systems shut off in crank position.
Just a thought.
Bruce

[76FJ55]

As stated, you may have power coming from ;;the wrong source. you need to make sure you have power to the coil from the 15 Bus (hot in both run ands start positions) I have attached a couple sections of the 1984 wiring diagram showing how the current is set up on a stock 3.2.

Power flows from the ignition "15 bus" to the input side of fuse 7, which then has a bridge connecting it to fuse 8. power comes of the input side of fuse 8 and goes to the coil.

since the power is on the input side of both fuse locations it is NOT going through either fuse and is therefore not a fuse protected circuit.

[78-911SC]

76FJ55 you were right on the money. Got to it this weekend and now I have spark. Much appreciated.