MS-II/Ignition module set-up how-to?

Bernard Fife · Post by **Bernard Fife** » Thu Oct 06, 2005 9:13 am

so my current setting of 'falling edge' with a trigger offset of 86 degrees btdc is is reality triggering on the rising edge of the signal if I scoped it right?

Jerry,

Yeah, falling edge from the module is rising edge at the processor pin, and the MegaTune setting is at the processor pin (This is confusing, I know, it arises from the historical development of the MS-II/UMS code).

This is an optical sensor in-the-dizzy, so I should be able to use falling or rising edge, and if I know the duration of the pulse in degrees I should be able to set it to 'rising edge' and subtract the duration of the pulse from the current 86 degrees and use this new trigger offset and get it idling exactly as it is now, correct?

Yes, that sounds right.

So how do I determine the duration of the pulse?

If this were mine, I wouldn't bother. I'd just set the input capture (to use the rising edge), then I'd set the trigger offset to 20Â° and use the trigger wizard to set the timing. (If you switch the input capture edge *and* change the trigger offset as well, you'll likely be close enough to start the engine. If not, play around a bit by rotating the distributor until the engine fires.)

Rather than changing the trigger offset in MegaTune to calibrate the trigger offset, you can do as you say and rotate the distributor to get the trigger at the specified 20Â°. Just leave the settings alone in the wizard, and rotate the distributor until the actual advance (on a timing light) matches the indicated advance (in MegaTune). Since you have 20Â° as the trigger offset, and the timing matches, you are 'calibrated'. Lock down the distributor and drive!

Lance.

FoundSoul · Post by **FoundSoul** » Sat Oct 08, 2005 11:04 pm

Thanks a ton for all of your help Lance- we've got this one going and after a couple hours of tuning have a pretty decent base tune going on it-- It still needs a little work but it's looking pretty good and making more power than the factory ECU was. I had to invert the spark output to keep the coil from charging when the engine wasn't running, thanks for the tip on that. We've got a pretty serious dip at 2500 we need to smooth out, and a bit of driveability tuning to do but we're well on our way. I ended up sticking with 'falling edge' and leaving the trigger offset pretty high, about 74 if I recall but the timing on the light matched the trigger wizard and the module isn't using this for cranking timing so it shouldn't be a concern.

Here's the current before (factory ECU) and after (with the MS2) dyno plot- no other changes were made:

Any word on knock correction with the MS2? We'd like to turn up the boost to 10 or 12psi and see what this thing can do.... This is the stock 7lbs.

Bernard Fife · Post by **Bernard Fife** » Sat Oct 08, 2005 11:15 pm

Jerry,

Very nice!

The knock sensor work is on-going, I believe, but I don't think anything is imminent. It will require a fair bit of testing and 'fiddling' to be sure it's right for general consumption, and this will take time.

However, this is a good place for programmers and experimenters to do some work, especially if their engine has a factory knock sensor and module (to eliminate some of the variables).

Lance.

FoundSoul · Post by **FoundSoul** » Sat Oct 08, 2005 11:40 pm

That's what I figured-- I just started a new thread with some knock logging questions here since they don't belong in this sticky....

FoundSoul · Post by **FoundSoul** » Fri Nov 25, 2005 12:07 pm

Here's some more info relevant to this thread--

In another thread someone had asked me about how I went about finding the proper trigger offset for the Subie I was working with here-- this is the basic approach I took:

I went the 'trial and error' route and Lance was extremely helpful-- I tried to document what I could in the thread you mentioned (EDIT: that would be this thread) , basically first I made sure I had my spark output (inverted or normal) set properly by making sure it wasn't charging the coil with the engine off and the ignition in the ON position, this is important to keep from cooking your coil. Then I tried both IIC options, Falling or Rising Edge, and played with my Trigger Offset and tried starting the car. Use a pad a paper (or notepad.exe) and record the results, such as:

TO=Trigger Offset

Rising Edge, TO 10: Wouldn't start
Rising Edge, TO 20: Almost started
Rising Edge, TO 30: Started and died immediately
Rising Edge, TO 40: Started and ran like crap, died after a few seconds
Rising Edge, TO 50: Started and ran a bit better, timing light showed no timing marks yet
Rising Edge, TO 60: Started and ran even better, timing looks to be a little ATDC still
Rising Edge, TO 70: Started and ran even better, timing looks to be about 0 BTDC
Rising Edge, TO 80: Started and ran even better, timing looks to be about 10 BTDC
Rising Edge, TO 86: Started and ran even better, timing looks to be about 16 BTDC

Give it the old 'dizzy twist' to set your base timing and use the trigger wizard to make sure it matches MegaTune. Note that you may need to do the above with Falling Edge as well and find what works best for you. It could be that the Rising Edge setting may not work for you and you need to use Falling Edge, don't let my examples above (being only RE) throw you off.

This is my trial and error method-- at some point I think I'll hit the pros here up for the scientific oscilliscope method but this will work for now.

Anyone got anything else to offer here-- comments/concerns? This method worked pretty well for me.

blown87 · Post by **blown87** » Wed Jan 04, 2006 8:02 pm

Lance, In the wiring diagram it shows a 100 Ohm resistor, but in the directions, it says 1 K Ohm resistor. Which is the right one and how many watts should the resistor be? I am installing this to use with a MSD ignition and want to make sure I do it right.

lance wrote:
It wouldn't surprise me if I needed a pullup there as well like I did to use the factory ignitor on my MR2 (MSnS-E pullup to 5v on the output)
Jerry,

Yeah, because this set-up isn't on the 'officially supported' list yet, I'd look to the MSnS-E documents as much as possible, while being mindful of the differences to MS-II.

The MS-II ignition pin (when connected direct to the port with the IGN-JS10 jumper in place) has an internal 5 Volt pullup, but it is only capable of 25 milliAmps max or so (10 milliAmps is safer).

This may not be enough current for your coil's transistor, so you might need to use the VB921 high current circuit (JS10-IGBTIN & IGBTOUT-IGN jumpers). This doesn't have a pull up in place, to add one see step #65 here:

http://www.msefi.com/msinfo/ms2/V3assemble.htm#output

which has this:

I figured you would have all the MegaTune and code stuff right. I think this thread is a good example for people to study when converting a new 'unsupported' module, so I'm trying to add more than is necessary (which I hope doesn't seem condescending).

We will get this sorted, and then perhaps you could post your mods and settings.

BTW, I am going to move this to the MS-II forum.

Lance.

Bernard Fife · Post by **Bernard Fife** » Wed Jan 04, 2006 8:31 pm

Blown87,

There was a typo in the diagram, it should be 1000 Ohm. 1/4 watt is fine.

Lance.

phasma · Post by **phasma** » Sun Jan 08, 2006 2:27 pm

Do MS-II support multi-coil applications? Such as distributorless 6 coil ignition for 6cyl engine?

Post by **efahl** » Sun Jan 08, 2006 2:28 pm

phasma wrote:Do MS-II support multi-coil applications? Such as distributorless 6 coil ignition for 6cyl engine?

No, just one ignition output.

Tadek · Post by **Tadek** » Wed Feb 15, 2006 11:14 pm

Hi everybody!

I wired up my MS-II that has been running at the stim for quite a while in my Saab 900 Turbo with Bosch LH2.2 Jetronic. What I am trying to do is run an ignition only setup first, then try to swap the fueling and as a last step try to figure out closed loop idle and maybe boost control with MS, but that is still a long way to go.

Anyway, since I would like to keep as much as possible in a stock setup, I want to use the Bosch ignition module and run the system with the Hall signal from the distributor to MS and the MS signal to the ignitor module. Seems pretty easy, so I connected everything yesterday, but did not have my laptop with me to check whether MS receives any signals. Now I have a few questions:

First of all, as far as I understand I (probably) do not need a pull-up resistor on the MS output when not using the high current driver but using the MS-II output on my ingitor module, as there is an internal pull-up to 5V. But do I need some kind of pull-up (or -down) when using the Hall signal as an input?
Another thing is, that I have heard from different sources who have their Saab ignition running on MS, that they used the Hall signal going to pin 6 of the ignition module as MS input and wired the MS output to pin 6 again. The MS Manual mentiones that one should use pin 5 of the Bosch module. As far as I understood, there is a kind of differential signal going to the module so that I suppose any one of those two pins shoudl work and you probably will have to have a look which one has the falling and which one the rising edge when ignition is supposed to occur.

One More question is, do I have to have all the other sensors connected (for example intake air temp) when running the ignition only. I do not need it for the map, but there might be some porblems with nothing connected there?!

Cheers,

Tadek