Mobeck Distributorless EFI Upgrade and More

Thank you Troy,
Greatly looking forward to seeing you back on line with more practical advice on the installation journey. I have already started unwrapping some of the electrical wiring to try and determine what the various circuits do, and if I can remove them without causing more problems.

I am currently struggling with rough idle issue on my 1988 HE and thought Ole’s modification would be a sensible option to trying to fix an outdated vacuum system, ignition system etc. He certainly makes a strong case for for bringing the car into the 21st century, not the least of which is better spark, less tubes, and reliability.

I have ordered a distributor - less system figuring I might as well go the whole hog: I had some distributor problems with my 1973 V12 Daimler, which involved the bushes in the shaft wearing and creating an eliptical rotation of the rotor, making reliable spark intermittent. Basically another moving part to eliminate.

Enjoy Easter.
Kind regards,

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Chris, how long between order and delivery for you? Ole put me on his list in January…. -John

@Bumnut1 I agree wholeheartedly on the rationale of using the kit vs maintaining the original systems. I want to spend my time driving and enjoying the car, not wondering if random vacuum solenoids are actually working, or if the distributor is advancing right. There’s more reason for it than that, but that alone is a big deal. And I think a lot of Jag V12 owners simply aren’t even aware of how out of adjustment their engine is really running. The previous owner of mine seemed unaware of how far out things were. It had effectively no advance function at all and ran with the timing retarded to somewhat make up for the idle valve being stuck open.

@John6 I ordered my kit on Feb. 8, 2023 and didn’t receive it until June 19, 2023. But Ole was very communicative and is working in small batches, so I get it. Still, I found myself wishing I had ordered earlier since I had planned on working on it in April and May to get it ready for summer. Of course I ended up going over the top with other stuff along the way anyway, so that timing was probably optimistic from the start.


Good morning John,
To be honest unsure. Ole is very much a cottage industry, and as he is constantly racing and developing the kits from his racing experience the production line may be interrupted In my Defence experience of these types of businesses things are produced when they are ready, not to a schedule larger companies would deliver to. I am currently number 84 on his build schedule, did you get a number? Kind regards, Chris

I don’t know my number. I do know the money is burning a hole in my pocket! When you have unspent money in the car budget and 20 cars demanding attention… the mind wanders.

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Too true! There are other optons I have seen when determining how to do a coil over conversion: in particular the Facebook page for the XJ-S. I asked the forum the question, and there are at least three options. However, Ole’s is the only truly ‘plug and play’ system the rest require quite a lot of auto electrical skills. Having said that Troy’s experience would suggest that even Ole’s kit needs quite a bit of Jaguar systems knowledge. I’m hoping to contribute to his journey whilst doing my own modification. My advice is hang in there the wait will be worth it.
Kind regards, Chris


In case you’re not aware, an XJ12 is being fitted with the same system. Progress is rapid!


Thank you for letting me know! Just caught up. His progress is very rapid, indeed. The job certainly doesn’t have to take as long as I’m taking. It’s also interesting to see him having some of the same questions and struggles I’ve run into. If this kit continues to be popular, it might be very helpful for Ole to smooth out some of these kinks, although some of them are probably due to differences in V12 versions and the cars they’re in.

Starting to get back into it now, though other things keep popping up to take my attention away again. But it’s finally nice enough out to open up the garage doors and enjoy being out there. And the sun stays up late enough to keep my motivation going.

I got my father-in-law’s '52 Buick out of the barn this past weekend and drove it to Cars & Coffee. My garage was very green for a couple of days.


Wiring time. This may be a question mostly for @Mobeck himself.

I’m currently working on getting the fuel pump relay wiring connected from the ECU which is now in the front to the relay in the rear of the car. Per the instructions, it is advised to use the former fuel injection harness connector to the ECU from the front of the engine bay to the back. So far, I’ve been trying to do the entire upgrade in a way that doesn’t destroy anything stock; it could all be un-upgraded by someone else in the future someday if that was desirable. So I’m trying to not cut into the wiring if I can avoid it.

With that in mind, I have so far wired up some bullet connectors into the injector harness connector (currently connected to one of the orange-green and orange-blue wires, but I may change that since there are two of each going back). So I should have a solid connection back to the ECU wiring connector on pins 13 or 14 and 27 or 28.

So now I’m wondering, could I get a small spade connector of some kind (advice/recommendations welcome) to plug into the pins I’m connected to from the front and then connect that wire to the #15 connection for Fuel Pump Control? I’m assuming that would be the red wire coming from the Mobeck wiring harness for the fuel pump relay. Is the green* wire simply a ground connection then? Or do I need to also get that wire directed all the way to the fuel pump relay? Or since I already have it connected, could I jump that wire over to the #1 pin for ECU ground?

I’m sure some will say just cut the wiring I need to use, but if I can get by without doing that, I’d prefer to. One bit of hesitation is that I’m not sure if a spade connector pushed into the ECU wiring connector will actually be secure enough on its own. Might have to cut into the wiring after all, but the wire routing questions remain. Thanks in advance for any and all help and suggestions!

*Green wire clarifcation: because we used the bullet style connectors, we needed to size up the wiring to get a good connection on the crimp connector. So the red and green fuel relay wiring is now red to red and green to black.

Ecu type contacts are known as Timer contacts, suitable male contacts should be available by size.

Example. 2.8mm x 0.8mm.
4130343.pdf (

Timer contacts.
Standard Power Timer Automotive Connector Contacts | Farnell UK

If you can’t obtain an appropriate connector, obtain a faulty Ecu and pull the one from that.


Hi Troy

OK, its fine that you have decided to use the free wires that earlier was for the injector signal coming from the ecu in the trunk. And it is fine to use a small flat spade at the old ecu connector to get the signal uut from this harness again.
But dont connect to the number 15 even if it say fuel relay. You need to drive the coil of the relay with both my red and green wire coming from my ecu. My red wire is always 12v and the green ground it through the ecu when it want to fuel pump to run, this is how all car electronics have been for the last 25 years. We always control through ground. Injectors and idle valve too, and the fan relay wires too. The red is fused 15A together with the +12v for the ecu. The other fuse is the +12v for the coils.
So please use the red and black as it is now after the big ecu connector and route these two wires to the coil of the fuel relay. You couls ofcorse installa new fuel relay too. But then you need to fuse the power side of it, and the original relay is already fused on the power side (contacts). My relay wires only care about the coil in the relay.
Hope this helps


Thank you! That helps. I’ll try to get some of those.

Thank you, Ole. I don’t know why I didn’t realize the green would be for switching, but that makes perfect sense to me.

So on the relay, it currently has the pink and black wire going to pin 86 and the orange wire going to pin 85. And I need to get the new red wire to pin 86 and the new green (black) wire to pin 85, right?

I finally got the idle valve connected! This was unexpectedly one of the biggest annoyances of the entire kit installation so far. I know there are variations in this aspect of the different V12 configurations, but one of the best ways to improve the kit would be including hoses and clear instructions for mounting the idle valve. Actually, making the instructions two or three times more detailed throughout would probably be welcome, but most of it’s clear enough. Anyway, back to the hoses. This is what I came up with:

For anyone else doing the Mobeck kit and stumped by this part of it, I’ll detail what I put together here. Overall, it’s just two elbow hoses, and elbow connector, and a straight reducer hose.

From filter housing to idle valve inlet:
1" diameter silicone elbow hose
1" coolant hose elbow connector to connect the hoses
1" to 7/8" elbow hose (Dayco 88445)

From idle valve outlet to intake manifold:
7/8" to 1" reducer hose (HPS HTSR-087-100-BLK)

All hoses were trimmed to fit, and even with all these bends and angles available, all the hoses are currently very flexed just to fit together. It’s far from perfect, and ended up being close to $50 in hoses and connectors.

But anyway, it’s on now and my to do list is getting shorter every day. I still need to finish wiring in the fuel pump relay and tackle some other items. ECU is mounted. I’ve got a forced one-week hiatus (vacation to San Diego) coming up, but I’m still hoping to have the car back on the road by the end of the month. And then I’ll need to tackle the headliner and get new tires put on. But those are problems for another day.


It is quite possible this has been upgraded since you bought it. Also the map has had many small upgrades.
Also, if you struggle the instructions say you can contact me.

Ole m

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Thank you, Ole. As always I appreciate your willingness to help and be available! This wasn’t meant to be a big criticism of the kit; just one irritation since there wasn’t a clear idea of how to properly mount it, nor an included hose. But when I was looking at your photos, and photos from the other guy on here who recently installed this same kit, the connections and available space look quite different to what I had in my XJ-S. For context, here’s your photo and then a photo from the other thread which can be found here: Mobeck V12 standalone EFI - #31 by IvanGrozny

Those photos show two different connection arrangements, and then my engine bay has a different amount of available space. So I can see how coming up with any sort of standardized hose/mounting solution would be difficult.

I think the only things left to do that are directly related to the kit are connect the 12V Positive cable, finish the fuel pump relay wiring, and seal off the holes in the right side filter housing left by now-unnecessary components. I know the instructions say to connect it to the “main + terminal on xjs.” And I’ve seen elsewhere that this is located on the firewall, but I don’t see anything there that looks like a positive terminal, and even if I did, getting to it at this point would be a pain. Is there another suitable location? Can anybody provide a picture of this “main positive terminal?” Thanks in advance!

Edit: Found the positive terminal on the firewall! It’s obvious once you realize what you’re looking at, haha.

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