Brent? Megajolt + Emerald

luxseven · Post by **luxseven** » Mon Mar 07, 2011 9:43 am

Hello folks (esp. Brent),

You may know from my other topic that I recently upgraded successfully to distributorless ignition with Megajolt. It's a great product and thanks to this community, installation was quite easy (if well prepared).
Almost at the same time and due to endless fiddling with the carbs, I planned to upgrade to injection as well. I bought a 'complete' kit with Jenvey throttle bodies a.s.o. and an Emerald ECU. This ECU also could trigger ignition in conjunction with controlling the injection. My idea was to add it to the existing Megajolt install, leaving both systems apart, one to control ignition, one to control injection. Thus, potential faults can easily be assigned to one system or another.
Except if you folks tell me that this makes no sense, that the Emerald should control everything at once, which would make my Megajolt install partly obsolete, although I can leave most of the wiring and sensors in.
Thanks for your input.
Cheers.

Jos

Post by **brentp** » Mon Mar 07, 2011 6:50 pm

If the Emerald ECU can accept a signal indicating engine RPM (many do) then you should be able to feed the TACH_OUT of the megajolt into the Emerald system.

As for whether you can have the Emerald unit control everything- this may very well be possible (we're not familiar with that system) but you want to carefully review what kind of ignition triggering mechanism it supports. If it can do the same high-resolution, high precision crank fired like the Megajolt + EDIS, then you should be able to go with one system. Anything less capable can be an argument to have both systems running together.

Hope this helps!

cng1 · Post by **cng1** » Mon Mar 07, 2011 9:48 pm

I know the Emerald systems extremely well. If you've got an Emerald then using a Megajolt in addition is madness as the Emerald is an incredibly competent system that can do everything you could possibly want and a stack more besides. Just hook the crank sensor output straight up to the VR input on the emerald, and job done. No need for Megajolt or EDIS modules.

Post by **brentp** » Mon Mar 07, 2011 10:06 pm

Thank you, Chris for the additional information.

luxseven · Post by **luxseven** » Tue Mar 08, 2011 11:31 am

Thank you Brent and Chris,

So this is possibly the route I will take.
As for testing, can I connect the tach out from Megajolt to the VR in on the Emerald?
I have one tach out available on the EDIS pin 11, can I use it as well (separate wiring)?
Answering this would help me while looking for the final way to install.
Cheers.

Jos

cng1 · Post by **cng1** » Tue Mar 08, 2011 11:43 am

Yes you can use tachout on the MJ to the input on the emerald. I don't know which firmware version you have on the emerald but if it is the K3 setup you will need to go into the ECU-config screens and change the input setup from VR to digital and change it from 36-1 to distributor.

Chris

luxseven · Post by **luxseven** » Tue Mar 08, 2011 12:58 pm

Thanks Chris,

This info helps a lot!
By the way, I'm one very satisfied customer of trigger-wheels !!!

Cheers.

Jos