efi swap ignition cuts power on "start" to computer

[BRONCO635]

efi guys how did you go about getting the computer to get power while cranking in "start" position? "on" loses power while cranking which will lose power to computer. I'm using stock ignition.i know i could put comp on a toggle switch but don't like that idea , sure theres a better way. thanks guys

 

[DirtDonk]

The Bronco's switch is "supposed" to have power to the ignition during START, but if yours is acting up, that might be what's going on.
However, there should be a separate wire (at least there is in most aftermarket harnesses) for telling the computer that the starter is cranking. That's not necessarily the one that powers the ECU relay, but just tells the computer what status the engine is in.

If your switch definitely does not get power to the RUN circuits (Green w/red and Red w/green) in START, then a new switch might cure the issue.
If not, then there should be some way to pull power from the START wire (Red w/blue) to do the job. Maybe a jumper T'd into the main wire with a diode to keep the starter relay from energizing when you just turn on the key?
Probably not that simple, but at least it's a start for discussion purposes.

What chassis and engine harnesses are you using?

Paul

 

[BRONCO635]

guess i should had explained a little more . sorry
im in the middle of a frame off. fired engine up this week (no body) hooked up junkyard efi harness and all is good.

have a brand new ignition sw that i was bench testing because i have heard of people having this issue

(no crank power to computer)and wasnt sure how they resolved it.
so basically im trying to get my plans together for permanent wiring once body is back on
thanks guys

 

[ren71]

The ignition switch terminal that goes to the stock coil resistance pink wire should be energized during crank/and run.

 

[BRONCO635]

Thanks I'll recheck that. I was ohming ignition sw out on the bench so maybe I over looked that.