Megasquirt

[bluesatin]

All ready to lock down the dizzy and connect up the megasquirt (ignition only running MSD on megasquirtnspark). Any tips/guidance on what I need to do/set in megatune prior to starting much appreciated!

Edited by bluesatin on Wednesday 11th April 18:43

[steve_d]

PM elliot he will know.

Steve

[bluesatin]

thanks Steve

[pb3]

I ran with basically the defaults and a auto-generated VE map. Started within half a second the very first time and idled well all from outside of the car. None of that revving business to keep it running. I did take an absolute age checking and double checking before hand though, partly because I am using the Ford EDIS-8 with twin coil packs so the timing needed to be right. A year and a bit on I am still tuning but am very pleased I went down the EFI route.

[steve_d]

Guy
Are you still using the dizzy as the trigger but letting Megasquirt adjust the timing from there?

Steve

[bluesatin]

Steve

Yes using the MSD system pro billet distributor as the pickup (locked) and then use this to give signal to megasquirt and then fire the MSD 6AL through the white wire. I have knock sensor, air, water and vacume to set the megasquirt with long term aim to run closed loop on the knock sensor for advance. Also hae lamda sensor to see if all is working ok.

[steve_d]

Thanks for that.
I want to go EFI so logically can control the spark as well but saw no point in going to a trigger wheel if I didn't have to. Nor did I want to bin the dizzy I spent good money on.

Someone will now come along and burst that bubble saying I have to have a trigger wheel for the EFI.

Steve

[davefiddes]

Recently converted my car from MS-Extra to MegaSquirt II and had to reset the timing to use a different trigger point (using the same MSD dizzy and 6AL). Procedure is pretty easy provided you've got a timing light that can handle the MSD multiple sparks. What I did was to set the engine using the timing tape to 10 degrees BTDC. I then lined up the vane on the dizzy with the sensor coil as best as I could and ensured that the rotore was lined up with No 1 plug.

With this in place I configured the MS to have a flat map of 20 degrees BTDC. Once the engine coughed into life I then tuned the dizzy position by hand till the timing light was as close as possible. I then tightened the dizzy and fine tuned the trigger position that the software had from the 10.0 degrees I'd entered so that the timing light value was exactly 20 degrees (had to pick the revs up a bit to get a totally stable reading).

I built my map based on the base values from American Speed (17 degrees @ 850 rpm and all in at 37 degrees @ 3000). At low MAP (high vacuum) I added 10 degrees to the value except at idle where I'm keeping it a bit more retarded to allow the fuel to burn better for emissions. More experimentation will be required...post MOT.

Some gotchas:
- When using the MSD box. Don't forget the pull up resistors for the dizzy pickup and MSD drive. This is on the MS instructions but can be easily forgotten.
- Get the trigger pulse input and ignition trigger ouput the right way round. It was reworded from MS-I to MS-II and I got it wrong. Caused some odd bangs as the ignition fired most of the way through the exhaust stroke!! Very hard to debug.

[eliot]

I'm not familiar with the MSD dizzy, but dave seems to have it about right. Essentially the megasquirt works as a time delay unit - it gets a trigger waits a pre-deturmined amount of time and then fires according to the table.
Dave - i assume you are configuring it as "next cylinder" mode with that trigger angle of ~10' ?

A trigger wheel is the ultimate in spark timing stablility - but you can get reasonable results with the dizzy - i ran a locked out HEI for a couple of years. Just upgraded it to EDIS8 because the simplicity appealed to me.

Adding a wheel to my stock damper was pretty easy:
www.mez.co.uk/ms14.html

Eliot.

[davefiddes]

eliot said:

Dave - i assume you are configuring it as "next cylinder" mode with that trigger angle of ~10' ?

Yep. That's correct. I converted to this to allow the actual undelayed pulses to be used during cranking which seems more accurate than calculating the timing.

The MSD dizzy we all mostly seem to use is just an electronic version of a standard points distributor. It's sadly not as clever as a 7pin GM HEI distributor which can run without any connection to an ECU for "limp home" mode.

I agree about trigger wheels. That's a next winter project though.

[eliot]

davefiddes said:

[quote=eliot] It's sadly not as clever as a 7pin GM HEI distributor which can run without any connection to an ECU for "limp home" mode.

So get a HEI, spray it red, rip the MSD sticker of your MSD(!) and hay presto!
The limp-home ability of the EDIS8 appealed to me.