Cougar Wont Start w/ Key

[nickleman60]

nickleman60 submitted a new Showcase Item:

1994 Ford Thunderbird

This car has a trac loc with 3.73 gears, ASP aluminum u/d pullies, 10% sc pulley, double i/c, ZR 3" cai, 70mm BBK tb, shift kit, cat delete downtubes, flowmaster cat-back exhaust, '97 sport brakes, clear corner lights, 17x9 silver Cobra R's with 245/45/17's and new paint. Motor has 75k on it.

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[Oldschooljp]

Hey fellas! Ive been trying to figure out why my Cougar will not start with the key. I can get it to crank and run by jumping the solenoid with a jumper wire (not with a screw driver across the lugs). Ive done some diagnosing and heres where Im at:
Ignition Tumbler: Dash lights up and a couple lights change and there is a click under the dash when rotated to start position
Neutral Safety: I disconnected the neutral safety harness and tested with volt meter. I am getting about 4.5 volts with key on. Goes up about half a volt with key in start position.
Starter Relay: Works as it should. Starts the car with jumper wire. 4.5 volts key on, jumps .5 volts with key in start position
Battery holds voltage, starter engages like it should, etc

I was doing some diagnostics and I figured Id try to get the starter to grind while it was running (running out of options by this point). I Started the car with the jumper wire, then climbed in the cab and turned the key to start position, of which nothing happened. I continued turning the key past the start position and the car died. I thought that was kind of odd. At this point im leaning towards the ignition switch (not tumbler) as everything else seems to be working semi-properly. I hate to do the work of putting in an ignition switch and it not be the problem. Any insight?

 

[35th]

When turning your key... Does the key spring backwards when you let it go from the start position and can you turn the key from off to acc...? If both happen then you can rule out ignition lock and the gear set the lock controls to engage the electrical switch

 

[Oldschooljp]

It does spring back after being turned to the start position. I have not tried turning it back to acc, but I will try when I get home tonight

 

[KMT]

The usual culprit is the multi-wire ignition switch down on the side of the steering column, inside the dash (not the lock cylinder assy.).

These are prone to fail when the shell/connector move apart over time due to thhe constant outward internal spring tension. They are less than $20 these days, I think, and should be easy to find. Note they do require a special security torx bit to R & R. Search here, there are several threads that cover the details such as watching it while turning the key to see if it tries to open up..

Ken

 

[Oldschooljp]

I bought a new ignition switch and tumbler, and installed them today. No change in symptoms

 

[351tt]

Test [ safely , engine off, wheels blocked, e brake on etc ] the continuity of the trans neutral switch with the harness disconnected .
You should also probably have more than 5V in the safety harness switch section ,I am pretty sure that is supposed to be full battery voltage , there may be voltage bleeding out or some part of it is shorting to ground when the load increases enough.
You will most likely need proper wiring diagrams and start tracing wires/line voltage from source [ Battery ] to the ignition switch and then out again , it will take a couple of people and some patience but you will eventually isolate the issue area .
Your switch may also not be mounted correctly in sync with the key tumbler section , I have not taken one of these models apart but some power switch setups are adjustable in relation to the key tumbler .
The twin turbo 87 Thunderbird ignition switch just crapped out , it will activate the starter solenoid but when I let go of the key and it returns to run , the engine shuts off , thought it may have been one of the comp relays [ it presently has a GN V6 Turbo engine in it ] .. took me a while to figure out if I held the ignition switch back from returning all the way but still disengaging the starter motor signal , the engine would stay running .

Dave.

I bought a new ignition switch and tumbler, and installed them today. No change in symptoms

 

[decipha]

bad clutch switch