Trigger setup for 36-1 wheel, previous MegaJolt installation

[Tom]

About a year behind schedule (thanks to an unexpected encounter with a tree), I've now got the VEMS installed and (almost) ready to take over from the distributor - at this point, it will just be controlling ignition.
I used to have a MegaJolt controlling the ignition, and just want to check I've got the primary trigger settings (in VEMStune) set up correctly - I'm a bit confused about some of them.

The trigger wheel (36-1) is set up with the missing tooth 90 degrees from TDC (as is standard with MegaJolt setups). I've got the settings currently as:

Edge: Falling
Type: Multitooth
TDC after trigger: 90
Number of teeth: 35
Trigger tooth: 1
Next trigger tooth: 18
Crank min period: 768

I've left everything else as it was.

[rob@vems.co.uk]

If you're using the newer firmware 1.1.8x on VEMSTune there should be a configlet to provide 36-1 out of the box

[Tom]

You're quite right Rob - I don't think it was on the version of VemsTune I was using, but I've downloaded the latest and it's there.

The default for TDC after trigger is 60 degrees - as my trigger wheel is setup with TDC 90 degrees before the trigger, I guess I should change vemstune to 270?

[z0tya]

if you use vr sensor, then Edge:rising

[GintsK]

Use trigger angle in common 45..66deg window. And rest of angle adjust by trigger tooth (2 or 3 in yor case).
In any case check with timing light! Under tools you can lock advance. If you want lock 0deg, type instead 0.25deg.
0deg do not work historically (in fact setting = 0 deg means "disable ignition lock" which it also says in the ignition lock dialog)

[rob@vems.co.uk]

You're quite right Rob - I don't think it was on the version of VemsTune I was using, but I've downloaded the latest and it's there.

The default for TDC after trigger is 60 degrees - as my trigger wheel is setup with TDC 90 degrees before the trigger, I guess I should change vemstune to 270?

The standard Ford fitment is with the missing tooth 90 degrees BTDC of cylinders 1 & 4.  If you've done it 90 degrees after then (assuming you're using a 4 cylinder) you've set it up 90deg BTDC cylinders 2&3 (assuming a 1, 3, 4, 2 firing order).

So you simply need to get your head round the fact that your setup will be indexed with a firing order of: 3, 4, 2, 1 and you will need to setup your injector and ignition tables to suit.
Its not difficult, but it can get a bit confusing at first.

[Tom]

Thanks for everyone's suggestions - yes, I'm finding this confusing 

The trigger wheel is set up as on a standard Ford - at least, I assume it is, since that's what the MegaJolt needed (I didn't fit the wheel myself). When I idle the engine with std dizzy + coil, the missing tooth is visible at about 10 degrees. Still not entirely sure what I should set 'TDC after trigger' to, but I'll fiddle with the settings until timing matches the VEMS advance value.

Had some trouble getting VEMS to fire the coil though (in that it wasn't firing at all) - having unplugged everything and come in for the evening, I've realised it was on 'Safe Mode', which it seems disables ignition & injection. How stupid do I feel? 

[Tom]

I now have the VEMS set up, and have matched the timings.

The MAP sensor (I'm using the basic internal version) seems to be working fine - I haven't really done much with the settings, expect for turning on the 'barometric adjustment', which sounded like a good idea. Any thoughts on that?

It's a slow process when you only have a few hours every week... and not much idea what you're doing.

Cheers for the help everyone!