Testing ignition module p/n 166-0785

[Ron Lerew 1]

Need some help. What is the best method of testing the operation of my ignition module p/n 166-0785 not mounted on my P220 motor? Any help would be appreciated before I buy another one. They do cost a lot.

Ron

Edited April 13, 2021 by Ron Lerew
Added pic of parts

[Achto 27,908]

 

 

Not up on my module testing, but some one should be along to help you out.

[squonk 41,633]

This is a thought only. Hard to tell without seeing it but I used to test GM ignition modules this way:

 

The module is usually triggered by a pulse. In the case of 74 to 90's GM's the pulse was from a pick up coil in the distributor. This pick up generated AC Voltage. So say a no start comes in. We would unhook the high tension lead off the center of the distributor. Or if it was an HEI unit we would have to line up the ign. rotor to a cylinder and unhook the spark plug wire to that cylinder at the spark plug. And then connect a spark tester to the wire and ground it. Then turn on the key and take an ordinary soldering gun at hold the gun near the module inside the distributor. The AC voltage magnetic field would be picked up by a good module and it would fire the spark tester 60 times a second (60HZ) 

 

So if the no start was no spark, after confirming the module was getting 12 volts we would try the soldering gun trick. If it sparked then, it was diagnosed as a bad pick up or crank trigger depending on what was used. If it didn't spark a module was the culprit 90% of the time. (sometimes we just goofed!) 

 

If you can apply 12 volts to your module with it's proper ground and hook a spark tester to the coil wire you may get it to fire with this trick.

[WHX?? 49,478]

Ron 

Check section 8 in this manual. Check the coil too. I know it needs to mounted on a motor but this all I can find for now. 

492-4006 Onan P216 P218 P220 P224 SM.pdf

Edited April 13, 2021 by WHX24

[Ron Lerew 1]

Thanks everyone for there help. Installed the ignition module back on the motor and did the test per the manual. It's bad. I'm looking for a replacement now.

Ron