GM DIS on MS3X

[Space387]

How are you supposed to wire and program the MS3 system for running a GM DIS ignition control module? As it stands I am using the 1x cam and 24x crank sensor and the car runs properly BUT there is no spark control. The ICM is currently forcing 15* advance unchanging. The system is wired spark A to the main input on the ICM. Is there anything I am missing or that I should change to gain spark control.

[jsmcortina]

I don't know the answer at the moment, but I'd like to help you make this work. I'll dig deeper tomorrow.

James

[Space387]

the setup I had to use with MS1 needed the main and the bypass. Tach signal was pulled from the Tach output from the ICM. Here is the guide I used for the original install of MS1
http://www.turbocamaroproject.com/megas ... Guide.html

[V6 SPL311]

If it's any help...
On my DIS MS2 V3.57 setup by DIY Autotune install I HAVE to use the following settings to have timing control.
I am using the on-crank reluctor wheel inherent to the 3.4 liter V6 chevy motor so the trigger angle won't translate, but I'll include all settings anyway.

Spark Mode= Basic Trigger
Trigger Angle/Offset=62.00
GM HEI/DIS options =GM Bypass on D16
Skip Pulses= 1
Ignition Input Capture= Falling Edge
Spark Output= Going Low (Normal)
Number of Coils= Wasted Spark
Spark A output pin= JS10
Fixed Advance= Use Table
Use Prediction= 1st Deriv Prediction
Cranking Dwell= 6.0
Cranking Advance= 3.0
Dwell type= Fixed Duty
Dwell duty= 50

If I had to guess, looking at the available options in the dropdowns, you'll have to change the wiring to spark B as spark A is not an option for the GM HEI/DIS block. Not many folks running the DIS/module combination. Took alot of reading and trial and error to get mine up and running. Still not optimized and I'm not positive on the dwell settings, but it runs well and nothing gets hot. I can post an MSQ if it is helpful to you.

Marshal

[jsmcortina]

How does JS10 connect to the GM DIS module? Directly or via other components ?

James

[V6 SPL311]

On the MS2 I believe it's just a jumper setting on the board itself that runs the control to pin 36. I run the relay board also so have the IGN (S5) from the relay board to the module. I can peel back the sleeve to get to the ignition module wire coloring if need be. I believe the timing control wire from the module was white, or brown. Been a couple years.

Also, here is a thread I had running back in 2012 when I was having the same problem.

http://www.msextra.com/forums/viewtopic ... 01&t=47046

[Space387]

on MS3 I am running strait from the 3x IGN A to the main trigger (pin B) on the DIS module. If I understood what the writeup said the DIS needs a 5v pulse to trigger, but Im not sure if the IGN circuits are 5v out or switching grounds. could very well be the problem if its the case.

[Space387]

OK!!! I think I have located the source of my problem. On the page for setting up DIS through the MS2 it says the sparkB is a 5V consistent to indicate the PCM is functioning and will give spark settings. If I can jump the 5V out to the bypass input it should be able take the signal.

[V6 SPL311]

Yes, the module needs 5v to avoid the "limp" mode which locks the timing, traditionally at 10 degrees. I use a relay so that the timing is locked during cranking, but upon firing, MS takes over timing duties. I always found it odd that the cranking timing setting in TunerStudio continues to affect start quality???

[jsmcortina]

Bypass is supposed to be controlled by the Megasquirt - there should be no need for relays etc. just connect it to Spark B output.

If this isn't behaving as expected I want to understand and resolve it.

James

[Space387]

that setting is only available if you are using basic trigger. I am not using the trigger circuit just the high res (24x) crank and cam sensor so wouldn't that throw the system off?

[V6 SPL311]

Okay, so obviously MS3 behaves much differently than MS2 and exceeds my knowledge/experience base. Good luck with your project and I'll continue to watch your progress. Always nice to have another 60 degree V6 out there running around on MegaSquirt.

[Space387]

yea it was a massive learning curve going MS1 piggybacked on the original ECM to full standalone MS3, and after toying for the last 6 months im still learning

[Space387]

Ok well that was fun... the 5V did the trick but whats weird is the idle is much harder to stabilize and the spark table I have carried over from MS1 is knocking( feel like it atleast) above about 2500. its not synce loss as it was working full rev range to 6k on the stock computer. Timing at idle shows the same 24* advance as with the stock ECM

[jsmcortina]

Okay, so obviously MS3 behaves much differently than MS2 and exceeds my knowledge/experience base. Good luck with your project and I'll continue to watch your progress. Always nice to have another 60 degree V6 out there running around on MegaSquirt.

In this area MS2 and MS3 should work the same - it is basically the same code.

James

[jsmcortina]

What vehicles were fitted with GM DIS ? I'd like to scope one out first hand to get this configuration nailed. I bet there aren't too many here in the UK.

Ironically I did have a mangy Pontiac V6 sitting on my driveway for a while a few years ago (awaiting a starter motor from the USA) but did not get chance to scope it out.

James

[93white3400z]

A lot of GM in America James.

Both my cars use GM DIS, 1993 Chevrolet Cavalier Z24 and 2001 Pontiac Grand AM GT.

[Space387]

figure any GM 60* from 1992-early 2000's and a few 90*v6's such as the 4th generation (93-02) firebirds and camaros the 60* fitted S-10 trucks and any fwd with a V6 in the 90's. Oh and the Northstars

[jsmcortina]

figure any GM 60* from 1992-early 2000's and a few 90*v6's such as the 4th generation (93-02) firebirds and camaros the 60* fitted S-10 trucks and any fwd with a V6 in the 90's. Oh and the Northstars

Only slightly more common than rocking horse do-da... I'm afraid.

James

[jsmcortina]

Right... I think I've found the issue here. GM bypass is not correctly supported at the moment. I'm working on it and expect to have a beta firmware release out today that does.

James