The Ford Schematic shows the Ford module earthed via the EDIS plug - ie not separately earthed to chassis
So can you earth the Megajolt via pin 4 of the EDIS ?
It looks like this is an 'internally-to-EDIS module' connected , perhaps 'cleaned', earth.
Thanks
Steve
Earthing the megajolt
Moderators: JeffC, rdoherty, stieg, brentp
Yep, It's generally recommended that you ground and power the MJLJ and EDIS at the same source, if possible.
Pin 9 is ground, too.
http://www.autosportlabs.net/MJLJ_V3_ve ... tion_guide
Regards,
Pin 9 is ground, too.
http://www.autosportlabs.net/MJLJ_V3_ve ... tion_guide
Regards,
Thanks Brent
The EDIS-4 etc connection picture diagrams actually don't show the MJL 'box' earthed ( or indeed powered ) and only show the PIP & SAW lines to it.
(I acknowledge the MJL plug wiring you made reference to does show power & earth connections)
I suggest on the EDIS picture part you could show the MJL box being earthed soley via 'clean earth 'pin 4 of the EDIS module.
The EDIS plug I got from the breakers had a 2ft long screened cable that carried the PIP SAW and pin4 Earth. I plan to connect these three wires to the MJL and power it via an cable that connects to the 12 feed to the EDIS.
The 'PIP/SAW/pin 4' cable screen is chassis earthed at the EDIS end.
That enables me to mount the MJL in a remote all composite area where no earth source exists.
Regards
Steve
The EDIS-4 etc connection picture diagrams actually don't show the MJL 'box' earthed ( or indeed powered ) and only show the PIP & SAW lines to it.
(I acknowledge the MJL plug wiring you made reference to does show power & earth connections)
I suggest on the EDIS picture part you could show the MJL box being earthed soley via 'clean earth 'pin 4 of the EDIS module.
The EDIS plug I got from the breakers had a 2ft long screened cable that carried the PIP SAW and pin4 Earth. I plan to connect these three wires to the MJL and power it via an cable that connects to the 12 feed to the EDIS.
The 'PIP/SAW/pin 4' cable screen is chassis earthed at the EDIS end.
That enables me to mount the MJL in a remote all composite area where no earth source exists.
Regards
Steve
That's pretty much what I've just done - I reused the PIP/SAW/pin4GND cabling from the original Ford loom, to connect to the MJ. I measured zero ohms between the EDIS pin4 and pin9 GND's, so fed EDIS pin9 with the ground as per the diagram. On mine the PIP/SAW screen is grounded at the MJ end though. Engine runs fine (statically, not driven it yet).steve100 wrote:The EDIS plug I got from the breakers had a 2ft long screened cable that carried the PIP SAW and pin4 Earth. I plan to connect these three wires to the MJL and power it via an cable that connects to the 12 feed to the EDIS.
The 'PIP/SAW/pin 4' cable screen is chassis earthed at the EDIS end.
That enables me to mount the MJL in a remote all composite area where no earth source exists.
Run the pin4 earth back to the vicinity of the MJLJ and connect that earth wire together with the MJLJ earth wire to a solid ground point.
Same with power for EDIS and MJLJ - source them from a common point.
Use at least 16G multi strand wire, heavier is better.
Remember that the earth from EDIS is carrying the ground side of the low tension switching and therefore also exhibits some pretty good spikes even if the wiring is good.
This charateristic is what that 22uF capacitor is about in the standard Ford wiring btw. It serves two purposes, one to help with suppression of spikes into the rest of the system and the other to provide a closer 'source' for the current surges demanded by the coils.
It will work with seperate source and earth points SOME of the time but why invite a later weird problem to chase for the sake of a bit of extra wire and effort?
Same with power for EDIS and MJLJ - source them from a common point.
Use at least 16G multi strand wire, heavier is better.
Remember that the earth from EDIS is carrying the ground side of the low tension switching and therefore also exhibits some pretty good spikes even if the wiring is good.
This charateristic is what that 22uF capacitor is about in the standard Ford wiring btw. It serves two purposes, one to help with suppression of spikes into the rest of the system and the other to provide a closer 'source' for the current surges demanded by the coils.
It will work with seperate source and earth points SOME of the time but why invite a later weird problem to chase for the sake of a bit of extra wire and effort?