RE: clutch switch...yeah, I trust myself when starting with the key. The problem is a remote starter. I often park in first (bad habit, I know). I'm going to have to wean myself off of that.
Tom, using a 5 pin relay like you describe has occurred to me but the problem is the "normally closed" function is only used by Cruise, which my truck doesn't have (and while I'd like to add it later possibly, it's not happening at swap time).
What I need are two normally open switches (relays), electrically isolated, for the start circuit and for the computer (start circuit should only go hot when key is in start AND clutch is down, but computer needs to go hot any time clutch is down with key in run...and the 'hot' comes from the computer itself for that*)
*: the clutch switch needs to bridge pin 30 on the computer to the signal return pins on the computer, so it cannot be fed by an outside source, it needs to just close the circuit between those two pins. I'm not sure what would happen if pin 30 was just permanently wired to the sig rtn pins, maybe it'd be fine.
Below taken from this thread on Corral:
http://forums.corral.net/forums/eec-tech/719667-question-about-eec-iv-pin-30-a.html
It's 5.0 stuff, but EEC-IV is EEC-IV (for the most part).
...with an auto, Pin30 sees 12 volts during start only. With a manual, Pin30 sees only signal return(ie. ground)...
If you have a manual computer, then you can get by with simply hooking Pin30 up to a constant ground. I don't know if that is the "correct" way to do it but some Ranger guys doing EFI swaps have done this with success.
Below taken from this thread on FTE:
https://www.ford-trucks.com/forums/460085-eec-iv-ecm-manual-and-automatic-difference.html
the ecm looks for a clutch pedal switch on the stick cars to hold the idle higher during gear changes
If that is true then it seems wise to have it switched as intended. That's also what I was kind of expecting the reason to be, kind of like a dashpot function (allow idle to slowly fall rather than just drop right off).
More operating theory (again not Rangers or 2.3 specific, but it's EEC-IV):
https://eectuning.org/forums/viewtopic.php?p=100507&sid=04fc56dcce0f30566127a02dad8b27a9#p100507
(specifically, the difference between stick and auto re: pin 30 - it works different depending on if ECM is for stick or auto)
Relevant summary:
Automatic EEC is setup to detect when the starter is cranking on pin 30 (+12V sent to pin 30 from ignition switch in 'start')
Manual EEC does not care if the starter is cranking and instead uses pin 30 jumpered to the blue/yellow wire to detect clutch and neutral engagement by sensing if the blue/yellow wire is grounded to pin 46 or not.
(irrelevant to my project but still worth knowing) If Manual EEC were used with automatic wiring, Signal Return trace in the ECM can be burnt due to short from ignition switch +12V source to the signal return (46) pin.
Since the EEC-IV uses +5V for all sensors I would guess the manual trans ones probably (?) output 5V on pin 30, when the circuit closes (clutch pedal down), that 5V (not 12V like comes from the ignition switch) goes back to the signal return pin. It's a guess, but probably a good one.