[Gmecm] Re: 4 cyl mod for DIS?

[William Lucke]

The double notch is just for synchronizing to TDC #1, so the 7 tooth 
wheel is really a 6 tooth wheel. Of these 6 pulses, a 6 cylinder DIS 
passes every other pulse to the ECM and a 4 cylinder DIS passes every 
third pulse.
With that logic, it would take a 12 tooth wheel to work an 8 cylinder 
DIS... the 8 cylinder module would pass every third, the 6 cylinder 
every fourth and the 4 cylinder every 6th.



Will




> From: Andrew Gibson <andrewsharyn at yahoo.com>
> Subject: [Gmecm] Re: 4 cyl mod for DIS?
> 
> Somewhere out there in the great blue internet I found a page with instructions on how to use dual GM 4cyl DIS to run ignition on a Cessna 4cyl airplane. It used double everything with reference holes drilled in the harmonic dampner. His application had the sensors 32 degrees apart to allow startup and cruise ignition timing and a toggle switch to switch in between.
>    
>   I think you could do the same thing on an 8cyl and have the pickup sensors 90 degrees apart. Two ecms would be required to make the est work. As the 4cyl dis uses a 7 slot pickup with two of the slots 10 degrees apart, tricking the module for base timing will be difficult. However I found out the module translates the 7 pulse per rotation signal into a 2 pulse per rotation signal for the ecm to better conrol timing and fuel. (I should know, my truck is using a distributor and est module with a 7748 ecm and throttle body off a 2.5L DIS motor)