Megasquirt MS3X to run VT-VY coilpacks

[Z.]

Anybody know how to setup the MS3X board to run VT-VY coilpacks?

 

Only information I can find is from people using previous versions of megasquirts and it doesn't seem to be applicable as they add another board to there version of MS to gain extra spark control outputs but the board they use has a "high voltage" output as compared to the MS3X which only puts out a "logic level" output and is not a high enough current to drive the coil directly. I'm  guessing I use the GM ignition module to be used to drive the coils and use  MS3To drive the ignition module. Not sure how though!

 

Any help greatly appreciated!

 

Also if anyone knows which wire is which on VT-VY ignition module plugs (13 wire plug) feel free to share. Thanks

 

Liam

[Six_Shooter]

VY-VT, being the 3800/3.8L, correct?

[Z.]

VY-VT, being the 3800/3.8L, correct?

 

Thats the one

 

If anyones interested I think I've found the best solution now.. It sounds like jumping the internal module on the gm coilpack plate and instead igniting the coils with a Z32 or similar ignitor being driven by the MS3X is the way to go

[Six_Shooter]

Alright I wanted to make sure before I posted any information.

 

With most of the GM DIS systems, the 3800 included the connections are very much like a dizzy. There are 4 basic wires needed between the ECM and the ICM. "Ref LO" usually black/red, "ESC" usually white, "REF HI" usually purple/white and bypass, usually tan/black.

 

The REF LO is basically a ground between the ECM and the ICM, to make sure they have the same ground potential.

 

The ESC is what actually controls the timing.

 

The REF HI, is the trigger to the ECM, in GM terms the signal is called a "DRP" or Distributor Reference Pulse. This will send one pulse for each ignition event.

 

The bypass will have 5V applied to it above 400 RPM is stock GM configurations, some Megasquirters like to apply 5V all the time and use the ECM to control timing during crank. This is also the wire that you disconnect to set base timing.

 

The other connections to the 3800 module include the crank sensor, and usually a cam sensor as well, though I don't recall if the ICM actually uses the cam sensor or if it's just a pass through on those modules.

 

I read people suggesting to tear apart the module and use some other MOSFETS to trigger the coils which makes the ICM itself pointless, other than for mounting, which could be done with a flat plate, if you go that route. I use the GM DIS myself, though I'm also using a GM ECM, the ECM and code I am using did not originally support DIS, and had to change some parameters to get it to work.

 

The GM ICMs have a built in LHM spark mode, that will have spark even with no ECM in the car, as long as it gets ignition, grounds and crank trigger. It's a great thing for diagnostics.

 

If you look in the Megamanual under the GM Ignition section you will see reference to the dizzy ICM, and the 2.0L and 60 degree V6 style ignitions. These ignitions require a 60* offset to work correctly, after start. The 3800 modules require a 33* offset to have correct timing, otherwise the set-up is very much the same as for a GM dizzy.

[Z.]

Thanks six shooter! Great bit of information there..

 

Still feeling my way through the info on these systems, there's a fair bit to get your head around but all very interesting learning how it all works. Good to have blokes with some experience willing to take the time to help us work out how to put it all together. Much appreciated.

 

I think I might just jump the internals and run a z32 or similar ignitor as it appears to be easiest way to set it up without having to add extra parts to the board and still utilize the expander board I got as well.

[Six_Shooter]

The easiest way is to use the ICM as it is.

 

The extra parts to add are a resistor and a couple jumper wires IIRC. A lot easier to add than modifying an ICM.

 

If you truly want to utilize the expander board, forget any DIS ICM and drive some COP coils, with built in ignitors.

[OZZ240]

I'm using LS1 coil packs from a V8 Holden Crewman, they have a built in ignitor, I got mine via eBay secondhand cost $140 for 8 they are a really good coil pack.

I'm not using Megasquirt but a Haltech.

[Z.]

Thanks for the advice fellas. I did actually look at putting a coil on plugs system in but I had a cheap supplier for genuine MSD DIS coil packs which was half the price it was going to cost for a set of new coil on plugs... Being a tight ass uni student that made mind up for me pretty quick

[Six_Shooter]

I hope MSD has improved their quality on the DIS coils. I know of quite a few people that had problems with the MSD dis coils for GM. Truth be known, they don't have much more power than stock GM DIS coils, specs wise anyway.