I want to convert the stock 3.1 from distributor ignition to dis for future mods . I got the ign parts from a 3.4 firebird laying around . I plan to modify the balancer to 7 slots for the crank sensor and set the timing 10⁰ before tdc . but im not sure if i need to do any ecm mods or is it just plug and play ?
thanks a lot

 

The ECM would likely need to have 6 drivers for the 6 coils. I don't know that you could do it w/OEM parts, without an ECM originally designed for running a DIS ignition system.

 

Ok what i know the ecm only gives the desired ignition parameters to the icm of the distributor
the dis module should work on its own
But i could be wrong

 

Maybe. It looks like you're going to need quite a few more sensor/inputs than your engine has, for the DIS module to work.

 

The Dis module only needs a crank sensor i will make a bracket and mod the balancer with 7 groves

 

Give'r hell.

 

The home signal is NOT 10 degrees BTDC #1, IIRC it's 10 degrees ATDC #4.

You also don't want to cut the grooves into the balancer, this defeats the purpose of DIS ignition. The outer ring of the balancer will shift back and forth while running to dampen the firing events and the crank speeding up and slowing between these firing events. You will get instable ignition timing. If the outer ring ever slips, which is not uncommon, then you have the timing out by however much the outer ring slips. Best way is to make a trigger wheel to either weld to the crank pulley or get sandwiched between, the latter way requires spacing out the accessories and accessory drive by the same thickness as the trigger wheel, though it is my preferred method.

No, it is not plug and play, while the signals between the ECM and ICM are virtually identical, there is a 60 degree offset (unrelated to the engine bank angles, as other GM DIS systems of the time used 60 degrees along with 80 degrees for offset timing), in order for the ignition events to happen at the correct time. I don't recall which parameters had to be modified offhand, but there is information on this in the DIY PROM forum, I recall a thread that either I started or was involved in way back in the late 2000s (under my old user name "The_Raven") about this as that's where I got some of the information I needed to swap the setup that I put on my 3.2L (0.030" over 3.1), to my Datsun 2.8L (inline 6), and used a different MASK (code/bin/tune) than I did in my Jimmy back in the early 2000s where I used a stock ECM out of a Cavalier. I also used this setup briefly on my 3.5L V6 that I swapped into my Datsun (picture attached, I can't seem to locate pictures of the previous engines).

You can see the trigger wheel behind the crank pulley in the first picture and the Sensor bracket I used in the second. The sensor bracket was actually a bit different when it was in my Jimmy and was placed against the block, I loved it forward for a few reasons, but still the same end result. I only made it adjustable originally because it was before I got into tuning that it was originally made and wanted some adjustment to get the timing right. Now I would just make the sensor bracket fixed and adjust in the ECM for any mechanical inaccuracy of sensor placement.