Lumenition reliability issues


I’ve owned my V12 E Type two plus two for 13 years by now. Six years ago, I swapped the original Opus ignition system for an Optronic Lumenition one. A standard one at first, then (one year later) a Competition Energy System as the seller (Autocar Electrical Equipment - London) deemed it more suitable for a V12 engine. That system has worked satisfactorily for these last 5 years.
A few weeks ago though, I experienced severe ignition problems : dead spots on acceleration from 2500/3000 Rpm, difficult re starting when engine hot. Strangely enough, these problems would only occur after the engine had run satifactorily for … say half an hour or so…And therefore had become quite hot,(without overheating though), the tickover remaining quite even. I changed the coil first, as I thought it might cure the problem. For sure it did, but not for long, as by now the situation has reverted to its initial stage. I’ve noticed that the coil and the Lumenition module do become extremely hot when these problems occur, despite the change of location I’ve deviced (at the rear of the engine).
Therefore my questions are :

1° ) Has any fellow V12 E Type jag owner with the same system fitted on his car experienced the same predicament ? I mean (maybe because of current planned obsolescence…)will the optronic module become in the long run more and more over sensitive to heat, as to become faulty at times ?
2°) Has the swapping for a brand new system solved the problem ?
3°) Has this new ( improved ??) Lumenition system proved really more reliable than the older one ?

Of course I’ve asked these questions to Autocar Electrical Equipment, but strangely enough, so far they haven’t bothered to reply, whereas they had before kindly offered me relevant advice for some previous ignition problems. Therefore I don’t know what to think…

Michel Vidal (Nicou) - Royan - France.

I have 10 years and 40K miles on Lumention setup on my 74’ etype. Not a single issue. I mounted the amplifier on the front picture frame. Not exactly sure what model Luenition is installed, but I will look tonight. Sounds like the issue may be more with the coil heating up than the ignition. Have you double checked the timing and/or made sure your plugs are not fouled?

Jeff S
Atlanta, GA

I know this post is old, but thought I would write a reply, in case people were searching for a similar fault. I had a similar issue years ago on my e-type v12. It would run for 20 minutes to half an hour, then it would play up and stop running. I replaced the rotor arm. Swapped the opus for a lumenition, still the same problem. Eventually changed the distrbutor cap which looked fine, and this solved it. The bush in the centre had broken down. Unbelievably 5 years later had exactly the same fault on a completely different car.
Worth checking if you have a problem like this.


1 Like

Well I had the same issues on my 4.2 69 etype
Would run great then it would start missing big time,would not restart when hot.
you know what I did, I went back to the points. But still had the same issues
What finally solved my problem was that the relay between the voltage regulator and the alternator was faulty. This caused the battery to discharge, caused the coil to overheat , low voltage to the plugs
Replacing that relay completely solved my issues. I mean Completely
Hope you have the same results I had.


I’ve been looking for some info on the Lumenition Optronics for V12, as mine recently installed is great so far apart from Tacho reading way high. So if anyone else goes this route some points.

  1. The instructions are naff and describe a few separate styles of kits with different wire colours.
  2. The kit CEK150 which needs fitting kit FK119, does not need the ballast resistor as comes with new coil etc, but comes with awful diagrams for wiring.
  3. The best diagram for CEK150 comes with FK119 but does not show any tacho resistor.
  4. You do need a tacho resistor of 6.5KOhm.
  5. The manufacturers do not respond to email or telephone, confirmed by SC parts support MC Monty.


Nicu how many miles have you put on the system…That system has been great but, if the car sits and in damp areas the usual happens. Condesation, dry rot on wires, .How many miles…

Hardly any miles as yet, we just re-built this motor, and are doing a comparison with all the after market V12 ignition options to see which ones hold up over time.


So 13 or 6 years with no miles?

Confusing as both avatars are green Ns.

I was just trying to help anyone doing the Lumenition on V12 E, as its been a bit frustrating sorting the tacho out, if I am not obliging some protocol or other I apologize.

Not your doing, no apology needed.

Joey replied to your post with a question for the original poster as, just by chance, you have very similar avatars.

This is how wars get started.

1 Like

I see now Sir, Thank you. I shall cease to be a green N soonest,

I am now in the process of fitting the Lumenition system to my 74 E Type.
Very confusing as they supply 2 different wiring diagrams, and the 1 I want to use is not very clear especially for the Tacho.
Any clearer instructions I would be most grateful.

See the link below Another Lumenition question-how to wire in a S3 - #8 by Steve_In_NOLA

You couldn’t by chance post a clearer wiring diagram of how you wired your set up because I’m not getting much help from the suppliers.

Mr RegH, are you using their full kit CEK150 with their coil?

I think a lot of the confusion comes when folks are trying to use the amp/pickup with the original ballasted coil. I will post exactly what I did shortly.

Mr RegH, Using their full kit CEK150 which has a coil and Amp, along with their fitting kit FK119, I found that the only diagram that made any sense in terms of wire colours on the amplifier was the one that comes with the fitting kit, (FK119) which I attach here. The diagrams with CEK150 itself are terrible and have the wrong wire colours.

CEM-installation new with violet cable(1).pdf (2.8 MB)

This diagram although a bit woeful is accurate to the kit CEK150. As it includes a new coil the ballast resistor is not used, and this is maybe why you now need a resistor for the tach to work, I’m not sure as I thought that the tach connection through that resistor module was straight thru low Ohms. Either way, if you use CEK150 kit with black amp and coil, (and do NOT use the old Lucas ballast cage) this diagram with the fitment kit which I assume you are using does work.

If you look at it you will note an unused resistor hanging in the breeze off the power, (I assume this is old ballast) and you will note no resistor in series with tach. This is wrong and where you need the resistor. Now I went back to the advice I took from SC and said, yes but what power resistor, and received what i though was an erroneous answer, i.e a 15W resistor, which is huge and I assumed a typo as it meant the tach required 1A or more which i doubted.

So I ordered 4 resistors at the required 6.5KOHM from Mouser, and these were 0.5W, and I used 4 to make a 6.5Ohm at 1W, with 2 in series in parallel with 2 more.

This is mouser part 71-CMF556K4900BEEK .

I soldered these in as described between the tach and the neg(-) coil connection and it immediately dropped the RPM to accurate from about 2X. Again, the wiring diagram I attach dores not show this resistor in series with the tach feed.

Autocar never answers, which is well documented. I am surprised they are in business.

Even more confusing is when you want to use a vacuum advance, which the later Lucas distributor 36DM12 uses with the injection system, whereas E-type uses 36DE12 with Vac retard. I am sure this confusion is documented elsewhere here. So to clarify, you CAN rebuild a 36DE12, with a VAC advance AND use this kit FK119. Nowhere could I find this answer so I just did it.

I hope this helps.

Let me dd something else too, If you want to mount the Amplifier on the front picture rail, where it is remote from engine heat, you will need to increase the length of the wires to the pick up in the dizzie. I made a completely new on engine harness which incorporated the wires to the oil senders, as the old one is invariably a complete dogs breakfast of aged wand heat affected wiring.


Absolutely great many thanks for your help.
The wiring diagram you sent is much clearer & I can now see where everything goes.
I just took the white feed off the ballast resistor & connected it to the + side of the coil along with the red wire from the amp and she fired up straight away even without choke.
I haven’t checked yet but the live feed appears to cut out when cranking the engine as she starts when I let go of the key, but at least she is running again, I can check that later.
The Tacho seems to work OK as I left it connected to the old B/R but I first need to tidy up the wiring before I take her out for a spin.

No Worries, I am sure its documented here but the white wire off position 2 does cut out as the blue straight tracer wire from the starter relay is supposed to “overload” the ballasted coil with 12V for more energy at start, and also, you don’t want all the stuff also off that circuit running as it includes fuel pump and also the alternator exciter circuit which would be detrimental to the start if the alternator was attempting to charge. You would have to develop a bypass or I suppose connect the blue tracer to the coil as well to provide spark whilst cranking but that would defeat the purposes just mentioned so you might need to get clever with another relay or such like.