Joe Pamplin

I have a 85 gt with 5.0/t5
I just got the car about a week ago, when I got it home it wasn't getting any spark from the ignition.
I replaced the following;
Distributor cap, rotor, coil, spark plugs, ignition control module, and spark plug wires.
Ok, spark problem resolved... (The problem was the control module.)
And now it won't start at all from the key (not even a click)
So, I replaced the following; starter solenoid, ignition switch, solenoid to starter cable, solenoid to battery cable, battery to block cable, and block to chassis cable.
Still nothing from the key, but it will start by jumping across the solenoid. (When l doing this it will only run for 5 seconds or so.)
All the fuses are good, starter is good, battery is good.
When the key is in the "on" position I have no power to any accessory.
Could this simply be a bad tumbler? Or do I have more extensive electrical issues?
Where should I start??? Thanks for any help!

Duncan_GT

Have you double checked all of your grounds since replacing the cables?

dawson1112

Its not the key cylinder. More likely its the ignition switch located below that in the column. The key simply allows the cylinder to turn pushing on a rod that connects to the ignition switch. But you say you have replaced that switch?

When you were replacing every thing did you disconnect the battery?

There are several fusable links in the ignition system on these cars.
Here is a schematic of the ignition system as it relates to the ignition switch plug.

Note the fusable links in the yellow wires to the bottom left. this supplys the ignition switch its power. If you have no accesorys at all ie radio , wipers , turn signals etc with the key in its on position you likely have a problem in the supply of 12 volts to the switch.
Meter the wires to see if you have any power at all there. If not its a blown fuseable link or a broken connection .

85gt 89coupe

This is joe Pamplin. Thanks for the help. I couldn't log back in under that account so I had to make another. The ignition switch is new. I will be back on the car Sunday and will go over everything with a multimeter.
What's the odds of it being a bad clutch safety switch?

85gt 89coupe

And yes, while working on it the battery was out of the car.

dawson1112

Id say the odds of it being the clutch inter lock sw are low because you have nothing with key on.

You should have radio, wipers, signals , windows if pwr applies.

Like Duncan says too double check all grounds .

lxman1

Check the fusible links coming off of the battery side of the starter solenoid.

And make sure they are all hooked up and on the battery side and not the starter side.

85gt 89coupe

Update:
12.5 volts at battery,
12.5 Volts at solenoid (hot side to battery)
The block is now grounded to the chassis in 2 locations (cleaned down to metal with sandpaper)
I have no voltage at the ignition switch.
All the fuses in the fuse box are good (0 ohms)
Nothing at the fuse panel has any power.
Are there any fuses that are not in the fuse panel under the dash that I'm overlooking?
Nothing works. Headlights, wipers, radio, dome light, fuel pump, NOTHING!

dawson1112

If you don't have any power at all to the switch, You have a burnt fusible link . Look at the diagram I provided in my previous post ,

Yolu will see the yellow wires should be 12volt constant. IF they are not the 16ga links are blown. This could happen if changing a part in the ignition and the battery was not disconnected.

85gt 89coupe

This beast is finally running good. It was a bad fusible link. I have now replaced the entire harness. I wish I could post pictures to show how bad it was before. Thanks again!