Question about Duraspark 2 Ignition System

[Jesse3877]

I'm very glad to hear things are working. :nabble_smiley_good:You've done some good diagnosis and now have a better understanding of how your ignition system works.You even surprised me with the 25 Ohm reading, but my '87 is wired a bit different.If your power while cranking is running from the (I) terminal I see how that makes sense.

Jim,

 

 

I was surprised about the 25 ohm reading as well. I thought that the ignition switch would be isolating the red and white wires unless you were cranking. I’m not using the “I“ terminal on solenoid. I was wondering what was still connected for there to be continuity and that’s why I pulled the “s” lead off. So then I thought maybe it was picking up continuity through the solenoid but not sure about that. If you look on the 81’ EVTM ignition diagram on the RH side of page there is a wire coming off the START position that goes to the right and ends. Not sure if that continues on another page but maybe I’m picking up whatever is on the other end if that wire.  

 

 

On a related/ unrelated topic, I purchased an aftermarket ICM, brand is BWD and part number CBE7P and it appears to have the timing retarding function working properly. If I take my my “s” lead off from solenoid And put it on battery (+) it retards my timing by 2-3 degrees. I had to hold it there for a second though so who know how effective it is during the very brief moment you are actually cranking the vehicle. A couple degrees is better than none!

 

 

Jesse

 

 

 

[ArdWrknTrk]

From some detective work Gary has done with his scope we figured that powering that lead adds a 1 millisecond delay, thereby retarding the ignition.

Yes, it works out to about 3 degrees at cranking speed, and helps a lot with hot starts.

[ArdWrknTrk]

From some detective work Gary has done with his scope we figured that powering that lead adds a 1 millisecond delay, thereby retarding the ignition.

Yes, it works out to about 3 degrees at cranking speed, and helps a lot with hot starts.

And thank you for that data point!

We can now add the BWD module to a list of confirmed ignitions with functional retard.

[Jesse3877]

And thank you for that data point! :nabble_anim_handshake:We can now add the BWD module to a list of confirmed ignitions with functional retard.

Good deal and you are most welcome.

Jesse

 

 

[Gary Lewis]

That 5A during cranking, which bypasses the resistor wire, is less than what I expected. As is the 3.7A for engine off & key on. So that says the DS-II module has more drop across it than I expected.

But the other readings are pretty much to be expected since the coil is only conducting a portion of the time while it is being "charged".

[Jesse3877]

That 5A during cranking, which bypasses the resistor wire, is less than what I expected. As is the 3.7A for engine off & key on. So that says the DS-II module has more drop across it than I expected.But the other readings are pretty much to be expected since the coil is only conducting a portion of the time while it is being "charged".

A little less than what I was expecting as well during cranking and running. Not sure if it would be relevant but I do have a PMGR starter. 

Regards,

Jesse