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

[Heo]

Hell i should have push started it by myself if there was no one to help me

[jmlay]

The starter relay pin 85 is the positive side of the relay, should be ~12V when measured with a meter,with pin 86 is the negative side of the relay. Pin 86 will be "open" when PCM is NOT allowing start, 2nd attachment. Pin 86 will be grounded when the PCM criteria is met to allow allow the starter to have voltage, 3rd attachment.

[cobracammer]

Going to give the wires a "once over" this weekend.  If still not fixed, I am just going to run my own relay.  This way I control ground (-) and ill pull signal voltage from the switch I have already tested.

[cobracammer]

Hi All,

Going to try one more time this weekend to find the glitch in the wiring and then I am just going to run my own relay to get a starter signal.

If im thinking about this correctly, the car has 2 ways of blocking the signal.  No voltage passing through the clutch switches and the other way is the PCM anti theft not sending the ground to the relay.

In my case, to bypass, I would hook up a direct feed and ground to the relay, and then a feed wire from my own switch (or ignition) and then another ground?  Do I have this right for a 4 pin relay?

Thanks

[jmlay]

I would insert 12Vdc at pin 85 of the relay first to see what that does, 12Vdc at 85 also feeds 12Vdc to the passive anti-theft. IF that does not work I would keep the 12Vdc at 85 and then put a switched ground on 86.

[cobracammer]

Thanks.  I was thinking that since I am going to be running a new relay to bypass the PCM and Passive anti theft, I might as well just install a push button start (so that I way I can run fresh wires to all areas?  I don't think I want to try and make the relay in the Bussed Electrical center work (Since this annoyance is taking a lot of time and this car is sitting there ready to drive at this point.......  with the exception of the starter actually working).

Something like this work???
http://www.jegs.com/i/JEGS-Performance-Products/555/10564/10002/-1

[cobracammer]

Got this just now:



Push button start that fits in the cigarette outlet of a 2005 Mustang.  Also comes with its own relay and the wiring. 

[Heo]

I thought about sugesting that but thought naaaa...
to crude in that car

[cobracammer]

My thought was to get it because then I can run fresh wiring to the starter without screwing with the OEM harness and possibly frying the Anti Theft module or the Powertrain control Module.  It looks like it will fit right in, and then I just need to extend the wire that goes to the Solenoid (Signal), Extend the power (to the mini buss bar under the hood), Extend connect the ground to a grounding stud, and then tap into a "Hot in run" wire instead of "hot In start".  This is because you would just turn the key to run (so the MSD ignition box and the fuel pumps are going) and then hit the "start" button.  At the very least I can get started with tuning the engine and stop worrying about the miles and miles of wires in this car (As the entire car is sensors and electronics).....  Guess I just got luck the first time I had it running.....  right up until the luck ran out.  LOL

[mike7570]

Don't forget to take care of that live yellow wire under the dash!

[TimeWarpF100]

Got this just now:



Push button start that fits in the cigarette outlet of a 2005 Mustang.  Also comes with its own relay and the wiring.

That button will do no good if the PATS system is not working properly.

I have messed with Ford PATS quite a bit recently on a Engine Swap Project.

I had the same issue as you are having. Turns out it was the PATS.  I would run a scan even with a cheap scan tool first to rule out PATS.

Check if any codes. If no codes it should be a easy fix.

[cobracammer]

Hey TimeWarp,

My thought was to bypass the PCM and the PATS.  It is my understanding that the Pats works through the PCM to supply the necessary ground to the relay (as an anti theft measure).  The Clutch pedal position switch then supplies the necessary voltage. 

My thought was to bypass the PCM and the PATS so that the relay has a constant ground.  Then as long as my Clutch pedal position switch is good, I will have 12V to send as the starter signal?

I understand that PATS also will stop the OEM fuel injectors and sometimes the fuel pump, but I am using the FAST EFI system so these wont be issues.  I only need to bypass the PATS system to get the starter to respond.  All else is controlled by a separate ECU (FAST efi)

[cobracammer]

Fount this diagram online.



My thought was:

Pin 30 - will be 12V(+) constant from battery
Pin 87- Trigger wire (+) to starter Solenoid
Pin 85- Constant Ground (-) so we don't have to worry about the PCM/ PATS supplying it.
Pin 86- 12V(+) from push button start switch.


Then on the push button start......



- Top wire on the Push Button Start goes to pin 86 (the person who made this sketch swapped their pin locations)
- Second wire will get 12V(+) from  a "Hot in Run" wire so the key actually has to be turned to run and fuel pumps running before you can push the button to start.
- Third wire will be a ground wire for the switch.
- 2 separate wires in the diagram I am guessing are power and ground for the bulb to make the switch light up .

Does this seem right?  I have to stress I hate wiring, but at least this way I don't have to worry about anti theft or Powertrain control module telling the car not to start.

[Heo]

Wire the start button with 12 all the time
sometimes you need to crank the engine
without fuel and spark

[cobracammer]

Thanks Heo. Good Idea.