wirign for unit with hard rev limiter - confused!

[16vescort]

Hi all,

I have wired up a standard MAP MJLJ unit in my mini and it runs spot on, now I have been asked to do the wiring loom and wiring on a mk1 escort running a 1600 zetec se setup.

This Mj has a hard rev limiter built in and I am really struggling to work out how i wire up the coil 12v feed.

On the mini it was the live from the EDIS supplying the coil, so that it works in "limp home" via the EDIS or MJ.

With the hard rev limiter there is another live out from MJ to the Coil.

My question is this:

Do I need the live from MJ to the Coil, from EDIS to the coil or both?? I have looked around the site and can't find any useful info.

Please help me.....

[brentp]

Hi,

You probably saw this, but just in case- here's the installation info for the Hard Rev Limiter:

http://www.autosportlabs.net/Hard_rev_limiter_1.2.0

With the rev limiter installed the 12V power going into the Megajolt is fed to the hard rev limiter board, and then out the "COIL_POWER" connector.

So, for wiring up the coil pack, it's like this:

+12V -> Megajolt power input -> COIL_POWER -> 12V power to coil.

When the megajolt activates the rev limiter board, it does it by interrupting the current to the coil pack. That's why the Coil has power delivered to it via the Megajolt.

The EDIS module is wired up normally with regular 12V power - it doesn't get 'interrupted' by the rev limiter board.

Hope this helps,

[16vescort]

So basically the coil has a 12v feed from the EDIS and MY "COIL OUTPUT".

Would it be safe to splice these feeds together before they pass through the bulkhead of the car - therefore only one wire on the engine side?

Cheers again.

[brentp]

For EDIS4, the EDIS module only has two direct connections to the coil pack- for firing each coil pack drive signal.

The center tap of the coil pack is *only* connected to the COIL_OUT on the Megajolt- this supplies 12V to the coil pack.

In your statement:

So basically the coil has a 12v feed from the EDIS and MY "COIL OUTPUT".

There is no "and": i.e. do not *also* connect it to +12V, it would defeat the action of the rev limiter. Only the 12V coil pack connection to COIL_OUT on the Megajolt

Hope this makes sense!

[16vescort]

So how would the limp home mode of the EDIS work - or in this case can I not have both?

I will need to re-wire it seems then as I have wired the live in from EDIS.

Thanks Brent - but could i ask you to update the wiring pages of the site as it wasn't clear.

[Funky Diver]

So how would the limp home mode of the EDIS work - or in this case can I not have both?

You do have both.

If you installed the EDIS and nothing else (ie MJLJ and Rev Limiter) the car will run in Limp Home mode. All, and I SERIOUSLY understate it here, the MJLJ is doing is optimising WHEN the EDIS produces the spark at your plugs.
Give it a try, disconnect MJLJ and your car should still run, and indeed is one of the first steps for installation.

I'm not so sure the install diagram and instructions are wrong per sé, I read it a couple of times prior to soldering, making looms, etc and all seems fairly straight forward to me.

[16vescort]

I know how to wire it up as I have installed it on my mini - and i have limp home via EDIS and the proper set up when MJ is connected.

edit: the penny has just dropped as the edis works on the earth side and not the live - schoolboy error!!

in regard to the wiring diagram - i would just suggest an amendment to incorporate the above as currently for v4 there is only a small note re the hard rev limiter.

[Funky Diver]

schoolboy error!!

They are annoying, lol

Least you got that bit sorted