To any one out there who has read, seen or heard about it, has come across any one who has a Jaguar V12 running on twin L-Jetronic (5CU) ecu units?
I have already been doing as much research into the system as i can and am in the process of attempting to try this with a V12 engine. Every thing i have read says it will work, in several different configurations, but i am still wondering how well each system would work on essentially a 2.65 liter engine (cylinder bank A and B combined equals 5.3L separately, 2.65L).

From what i have read, one of the things the 5CU system needs is signal from the ignition coil, to generate a pulse signal for proper injector firing - 2 injector pulse per cam revolution (the "fire, skip, skip, fire, skip, skip). What with a 12 cylinder distributor, use of the twin coil ignition system (one coil for cylinder bank A and one coil for cylinder bank B) would generate the needed coil pulse signal needed for each ECU. Each coil only operates 6 cylinders so the 6 coil pulses equal 1 cam revolution.

The second thing the ecu needs is signal from the mas air flow meter, Because Data from the Mass Air Flow metier is designed to give an air flow reading from 6 cylinders, one could use only one Mass Air Flow metier to read from only 6 cylinders, (read from either Cylinder bank A or B but not both) and send data back to both ECUs together, or two Mass Air Flow metiers to send data from both cylinder banks separately.

 

Are you converting from D-Jetronic, or a carburetted car ? Getting L-Jetronic to work will see you setting out on a long journey of discovery, I reckon. Why not just fit the latest version of the D-Jetronic that went on the last of the V12s, (the 6 litre cars) ?

LUCAS EFI / AJ6 Engineering

 

I'm not using D-Jetronic for a couple reasons. One, though i have a fuel injected V12 engine, i don't have any of the D-Jetronic fuel system to go with it, Just a "long block" V12, I will have to get a distributor for it though. Second, i have (minus 1 throttle assembly, 1 injector resistor pack), two complete L-Jetronic systems with an extra Mas Air Flow meter (if i can find it).
And lastly, i have been working on and with the L-Jetronic system for quite a wile, but so far have not tried the the system on any engine other then a 4.2 liter XK6 engine. I've been trying to get my hands on a working 6 cylinder engine with distributor ignition in the size range of either much smaller then or a good bit bigger than 4.2 liter, but so far i have only found a few engines (in my local area) only with fully electronic ignition, that the people selling the want several grand for, and i'm not going to pay several grand for a test toy.

 

I think your best bet is an aftermaket system that uses a crank trigger. You would simple install a 6cyl crank trigger wheel and two pickups, one for each ECM but 60 degrees apart.

Have a look at this....
http://www.fixedbygary.com/efi/index.html
This enterprising chap used two GM systems.

 

If keeping a cost to a minimum is a goal i would keep with one of the systems jag used on the v12 and keep it simple. If you do anything custom you are going to spend a bunch of time and money getting it right. So yes it is probably possible but in the end is it worth your time figuring it all out is the question you need to ask yourself.

 

Keeping the cost to a minimum is not really a goal i had in mind though at the same time i don't want to have to go buy a hole bunch of new parts, at the same time i want to stay with a injection system i know and trust wile at the same time doing something unique.