My 427 SOHC Build..... Finally the time has come!

[cobracammer]

Thanks for the offer.  I am going to see if I can pick up a pair of my own  :0)  Might as well have them seeing how much wiring is in this car  LOL  Thanks again

[cobracammer]

OK, did some more super sleuthing.  So its not really straight forward.  Its actually kind of ridiculous and I miss my 68 Fastback at this point.  What did that thing have like 3 wires?  LOL

OK.  So I found out that after the Clutch starter switch, the signal goes through the Powertrain control module (sort of another little computer).  The PCM is actually in the engine bay attached to the Bussed Electrical Center.  IN addition, the PCM actually receives a signal from the Passive anti-theft transceiver (telling it that the correct chipped key is being used).  This them lets the PCM power up the relay in the Bussed Electrical center and sends the signal to the starter solenoid.

So not a straight shot from the clutch starter switch to the relay as previously thought.   I can say that when I use the key to try and start the car, the passive anti-theft light functions normally.... So I am thinking that its ok with the chip (Otherwise it would go into lock down and blink repeatedly after trying to start).  So either wire is bad on its way to PCM (which I doubt as I did not hit anything during installation and all of these wires are in a 2" bundle harness ......  or PCM issue?  LOL

[Heo]

You have there from  PCM to relay a light green /yellow wire
The lose wire you had was green and yellow wasn't it?

[cobracammer]

Hey Heo.  No its a solid yellow wire.  Also PCM and relay are about 9 inches apart, so I am thinking their wiring would be all under the hood.  Nice catch though 

[Nightmist66]

Hey Jason, here are some diagrams I dug up for you per Ford.








These are laid out in order from clutch pedal switch where you said you have power to the Bussed Electrical Center, where the starter relay is located. Looks like you need to trace the red and light blue wire through the circuit and find where the problem lies. I've tried to include the connectors you need to check with location(on vehicle) and pin locations within the connectors. I also included a quick reference of the starter relay at the end. Hope this helps you more.

[cjshaker]

Jared, where did you find those at? Does Ford have a web page that has their schematics on it?

[cobracammer]

Thanks Jared!

[Nightmist66]

Jared, where did you find those at? Does Ford have a web page that has their schematics on it?

Doug, I got these from the Ford site I use at the dealership I work for. I can access the same info. at home if I want, provided I use my login. Unfortunately, the site isn't open to everyone.

[cobracammer]

I was noticing the differences between the diagram I found online and the diagram Jared was kind enough to pull for me using the cars exact VIN#.  Interesting....

So using Jareds Diagram, I crawled back under the dash of the car late last night and saw something interesting.  There are "2" switches!  There is a switch in the clutch area (the one I tested with the tester light probe) which you complete the circuit by pushing in the clutch pedal and pressing in the plunger.  And then.....  There is another switch on a bracket all the way at the top of the clutch pedal which you complete the circuit when you press the clutch pedal down and let the plunger out!  I should try to test that one too.

Also, using Jared diagrams, if I understand correctly, we have 12 volts coming from the Smart junction box to the CPP (which I understand now is the top switch and not the bottom one) via a RD/LB wire.  Then from that switch, the same RD/LB wire goes to the relay in the Bussed electrical center and then to the starter solenoid.

What is unclear is:

The clutch switch I have been testing (and shows power) located at the bottom side of the clutch pedal assembly where you complete the circuit when you push the plunger in is not shown on the diagrams.  Where does that power go?  LOL

Also, I see that although the top clutch switch (CPP- where when you push the clutch pedal down, you let the plunger out) feeds 12 V directly to the Bussed Electrical center Starter relay, it has the Passive anti theft device tied in some how (as per the diagram).  What's happening there?

and thirdly, assuming I can not figure this out, how can I rewire this so that I can "safely" get this car running?

Thoughts?    ***Amendment- the 2 switched associated with the clutch pedal are:  Clutch Starter Safety Switch (bottom switch- which I tested and the switch is good and there is power at "start")   the other switch which is at the top of the pedal assembly is the CPP or Clutch Pedal Position switch (which is the one in Jared's Diagrams above) that I have not tested yet.

[cobracammer]

Just another thought.  It looks like (from the diagram) that the Clutch Pedal Position switch supplies power (+) to one side of the relay (Pin 85) and the PCM by way of the Passive anti theft system supplies ground (-) to pin 86.

Am I correct on this?  If this is the case, I could check ground at pin 86, and that way rule out the PCM and the anti-theft system (I'm pretty sure the anti theft system is ok given the reaction of the indicator light on the dash).

I just find the wiring diagram at the point of the relay a little confusing.

[cobracammer]

OK, multiple posts- yes, but I want to get this all out (instead of on doodles on scrap paper)

-Battery Tested 12.6 V with Multimeter

-Voltage to starter Motor tested 12.6 V with Multimeter (using the starter case as the ground)

-Jumped the starter with a screwdriver and the starter and solenoid worked fine.

- Smart Junction box fuse location F2.21 (Starter relay circuit, PCM Key Off) tested good with the test light probe.  Fuse not blown.

-Power to "clutch starter safety switch" tested good with test light probe.  This is the switch at the bottom of the clutch pedal assembly that the plunger is depressed when you push the clutch all the way to the floor.

-"Clutch starter safety switch" tested good itself with Ohm setting on Multimeter.  Shows "OL' with switch open.  Push the plunger down and the multimeter shows 00.00

-Tested starter relay in bussed electrical center.  Pin location 30 shows constant voltage with the test light probe.  Pin 85 (Starter Relay, Control), Pin 86 (Starter Relay, Feed) & Pin 87 (Starter Relay, output) Show nothing with key in start position.

-Constant power to Pin 30 on the relay is fed through Fuse F1.4 (Pink cube fuse in the Bussed Electrical Center next to the relay itself).  This proves Fuse F1.4 is good.

What I am going to try next.......

- Pin 85 (Starter Relay, Control) should be a ground (-) supplied by the PCM (powertrain control Module) and the PATS (Passive Anti-Theft System).  I want to test that this Pin location is showing a ground with the key in the start position.  I will use the Ohm's setting on the Multimeter (One lead in the Pin hole and the other lead on the (-) Battery terminal to ensure the PCM and PATS are sending the ground (-) signal at start up.

- Although I checked the Clutch Starter Safety Switch, I just found another switch called the "Clutch Pedal Position Switch" which is actually the switch all of the diagrams are referring to.  There is a wire (Red/ Light Blue) which feeds into the switch (coming from the SJB) and feeding out of the Switch to the Bussed Electrical Center (Relay Pin Location 86- Starter Relay, Feed)

This is where I am at the moment   

[Heo]

my head hurts 

[mike7570]

If I had a car with a brand new SOHC that was run in on Jay's dyno just begging for the first real drive, I would have given up and run a new wire from the clutch switch to the starter solenoid and go drive the car!
Come back a mess with the wiring after getting a bunch of miles on the thing.

[ScotiaFE]

X2 Mike.
The hot wire would have come into play along time ago.

[68fecyclone]

If that car was mine it would have been started four pages ago, just to here it running.  Then deal with the wiring. A simple four foot piece of wire to the starter and battery each time it needed started. . Rob