EDIS on MS2- limp mode? can't adjust timing

[mikesarge]

Just installed an EDIS setup on my 1980 911sc running MS2 v3.57. I've got a clewett 36-1 wheel and magnetic sensor/mount.

Much to my surprise, it fired right up pretty enthusiastically on the first shot. Idling and revving in neutral pretty nicely too. Tach works, and we're getting rock solid rpm signal to megasquirt.

For initial setup, I've got my timing set to "fixed timing" at 10ºBTDC. However, My timing light is showing something closer to 25º or 28º maybe..



I've tried the "trigger wizard," and I can add 20º or -20º and nothing changes. We're still showing the same thing on the timing light. Same amount of advance is also true on the other coils, checked against their respective timing marks on the pulley.

I verified my wiring,
Pin 1: MS pin24 (shielded)
Pin 2: Tach signal
Pin 3: MS Pin 36 (shielded)
Pin 4: VR- (black wire on the magnetic sensor)
Pin 5: VR+(white wire on the magnetic sensor)
Pin 6: shields for VR and pins 1, 3
Pin 7: 12v+ switched
Pin 8: ground

I recall reading somewhere that if the wiring is wrong, it goes into a "limp mode" with fixed timing, so the only thing I can think is maybe the VR is polarity swapped, causing this condition? but I can't imagine it'd run at all with the polarity swapped, and it doesn't make sense to me that that would cause an extra 18º of timing advance...

Is it possible my timing light is wrong or incompatible with EDIS? (it's a basic strobe with programmable timing offset)

Anyone have any thoughts on this one?

[mikesarge]

apparently i'm having trouble with picture uploads...

ms settings:



timing light results:

[TimT]

I'm not to familiar with MS, but it looks like you need to input trigger offset.

The missing teeth occur a certain number of teeth before TDC. So the ECU sees the trigger , then waits X degrees to fire cyl 1

Not sure about fixed advance setting...

It seems like your ignition set up needs tweaking.. If the trigger offset is correct.. other values can be zeroed.. and your timing light should indicate 0 deg advance at idle..

[mikesarge]

Originally Posted by TimT

I'm not to familiar with MS, but it looks like you need to input trigger offset.

****

If the trigger offset is correct.. other values can be zeroed.. and your timing light should indicate 0 deg advance at idle..

That's exactly right. My issue is that the software is not reacting to any trigger offset inputs, whether they be small or large.

[TimT]

Count the number of teeth from the missing tooth, to TDC on the trigger wheel .. and input that value as trigger offset.. Input it manually

I am more familiar with Link, Haltech, and MoTec... and have done a few SDS, and Tecs

If the missing teeth are 10 teeth before the TDC mark try 60 deg offset

[mikesarge]

Yes. I understand the basic function. I know what trigger offset is. I know how to put it into tunerstudio. My issue is that regardless of what the software shows the offset as being in the settings, the actual timing does not react to the input

So, to be clear: my problem is two-fold.

(1) The timing on the timing light is not the same as the timing in the computer; and,

(2) It seems as though the timing in the computer cannot be adjusted

I am not concerned about problem (1), except that it may be a clue as to why problem (2) exists.

Other updates: I have verified continuity for the SAW wire, and ran it without SAW and had the exact same outcome. Seems like EDIS is running in limp mode and either my timing light is off, or the toothed wheel got installed wrong on the pulley.

So, I think the next step is to pull the ECU and verify everything is good in there. I have modified my board a little to add a baro sensor, but that mounts to JS5, so there shouldn’t be anything done to JS10, but it’s worth a look I guess.

[phelix]

On the Clewett pulley where is the missing tooth with respect to TDC?

[mikesarge]

The missing tooth is between Z1 and 30*, about half a tooth closer to 30* (see photo)

[al lkosmal]

Mike,
There may be a few things happening here:

A VR sensor with the polarity reversed will offset the timing by 25 degrees or so.....and

very often the timing light with dial offset get confused with the EDIS wasted spark mode. not sure if that is the issue , but worth verifying.

EDIS-6 is set up for the missing tooth to be exactly six teeth (60°) ahead of the VR sensor.
The Clewett is not set up to that configuration....so you need to set the tooth offset to compensate for this.

[rwest]

Hi Mike,

Here’s a picture of my settings for EDIS in my MS-2 set up with a Clewet wheel.

I don’t have a cam sensor on my car.

Good luck to you

[stownsen914]

Agreed with Al about the possibility that the adjustable timing light could be giving false readings.

Is there a chance that the MS is ignoring some of the attempted timing inputs because it's set to fixed timing?

[mikesarge]

Ok, so setting aside the trigger offset issue and just looking at whether the EDIS module is doing anything or not, it does appear that we're getting a SAW signal to the EDIS (see video)

https://youtube.com/shorts/v5frYVu56kU?feature=share

Now, the question is whether the EDIS is doing anything with it, or staying in limp mode.

I have a new (dumb) timing light coming today, so I'll try checking again, but for now, it appears as though adjusting the trigger offset still does nothing. I have adjusted the timing by a few degrees in either direction with the distributor many times, and seen/heard significant difference in how the engine runs. Here, I can add or subtract 20º and it makes no difference in how it runs, also, I can remove the SAW wire from the plug and it makes no difference, so I don't think it's actually doing anything, which leads me to believe it is in limp mode, and not using the SAW signal.

[al lkosmal]

Mike,
Saw looks like it is working...could be a faulty EDIS module...let me know and I'll ship out a new one.

regards,
al

[stownsen914]

It may be worth checking out the MS forum when troubleshooting, it's a pretty active forum.

Ran across this thread. May not address your specific issue, but searching or starting your own thread might be helpful.

https://www.msextra.com/forums/viewtopic.php?t=63390

[rswannabe]

Dumb timing light probably on work. The issue is the wasted spark system acts like a 2 stroke motor and you need a timing light with a wasted spark or 2 stroke setting.

[mikesarge]

SOLVED

Just to put a bow on this one: I had a faulty control module. Probably not a very common problem. Swapped modules and now we’re in business. Thanks to everyone who helped troubleshoot this one!

So, for the benefit of the archives: if you can verify a 5v square wave coming from your megasquirt, but can’t leave limp mode, you probably have a bad EDIS controller.

[al lkosmal]

Mike,
Just received a tracking update....your new EDIS module is due to be delivered to you....today.


regards,
al