Thunderbolt IV ignition output signal

[Mach 1 Spitfire]

Boaters,
I was wondering what the output signal from the distributor should look like. Analog or Digital. Usually analog on most ignition signal generators. With a shop lab scope or DVOM, and if the distributor was spun, what type of output signal will be produced at the two terminals. Will the output be on the red tracer wire, or, the green tracer wire that goes to the interrupt switch and coil. The manuals, SELOC or Clymer, do not cover this output testing procedure. If anyone has done this test, please drop me a note.
Thanks,
Doug

 

[Don S]

Re: Thunderbolt IV ignition output signal

Go up to the Adults only sticky and download the OEM service manual fo your engine. But there isn't any info on scopes.
What are you trying to figure out. There is plenty of troubleshooting information in the manual.

 

[Faztbullet]

Re: Thunderbolt IV ignition output signal

That question was brought up in service school years ago. Going thru some old notes we where told it was square wave.

 

[JustJason]

Re: Thunderbolt IV ignition output signal

It is a square wave. I've never hooked one up to a scope but it is a collapsing field hall effect type sensor. You could consider it a switch, because it is either ON or OFF. The field has either been broken or it has not. That would make it a digital pulse.
With the merc's i believe you get 5+VDC on the red tracer. When the switch is open (field not broken) you get those 5 volts back down the green. When the switch closes (field is broken) you should get 0VDC down the green.
But.....
Your not going to pick it up on a DMM... or even an analogue meter. It happens to fast. You would need a special scope that samples exceptionally fast to see it.
Bottom line is though.... if you follow the troubleshooting steps in the Merc manuals to the letter... then you don't need to own a pricey scope.
Hope that helps.

 

[Mach 1 Spitfire]

Re: Thunderbolt IV ignition output signal

Jason and members,
Great info. I have access to a good scope and will see what develops.
Doug