Mobeck Tekniske has developed a “plug & play” Bolt-on EFI kit for the Jaguar V12.

After one and a half year of designing and testing it is finally ready. The problem solver for all Jaguar V12 engines.  If you have any of the phenomenons mentioned below on your 1975 to 1988 V12 you shold keep reading.

Do your V12 have:

  • High fuel consumption
  • Low idle when it should be high
  • High idle when it should be low
  • Fouling at Idle
  • Lacking power
  • Variable reliability
  • A lot of smoke behind at startup and idle

Have you tryed this:

  • Overhauled all injectors
  • bought a new ignition amplifier
  • Boght any new vacum solenoids
  • Fully understood the vacuum system
  • Exchanged the thermoswitch at the rear of the right cylinderhead
  • Bougth a new Idle valve 
  • Syncronised the throttles
  • And so on…

Well, if you haven’t started on it, you will learn it, and if you have you are probably nodding approvingly.

So, after many years of dealing with Jaguars and it’s great V12 engine I have seen the need of a complete problem-fix kit.

Throw away this

If you start in one end and try to completely understand the vacuum systems for the ignition advance. Then hunt down the solenoids and buy them, and then find a coulpe of injectors fail, and the amplifier is broken and so on. You normally end up spending a good driving season and lots of money. If you are good and manage to fix it you still end up with 40 year old technology.

So here are a few pictures of the new Bolt on kit

Design of the ECU casing
New engine harness
ECU with fuses and relay
Ethanol aproved fuel lines
New injectors with mounting brackets
Injectors in place
Remove old IAC valve, mount blanking plate and new ECU contolled active valve

You can make a V12 run in a day, but to make it run as intended from the factory takes some effort. And I dont want (preferably not) to take my customers money to make it as a mint 40 year old system anymore . The most recognitionable signs of the need of this kit is, high fuel consumption, wrong idle level and smoke at startup. So I have developed this system that bolts on and looks very originlal with harness and everything, and if makes the V12 run correct.

The kit is delivered with these parts:

  • New Air and Coolant temp sensor
  • New terminated harness with connectors, fuses and main relay
  • 12 new Bosch injectors with 10 Degree spary cone
  • Ethanol aproved rubber hoses with mounting clips
  • Injetor brackets, laser cut stainless steel
  • new electronic controlled idle valve
  • Blanking plate for the old Idle air valve
  • Coil driver with heatsink
  • Coil
  • Control wires for Fuel relay and fan relay
  • New MAP sensor
  • New modern ECU delivered with a map for a std engine
  • Optional wideband Lambda sensor.
  • Installation manual.

The great thing about this kit is that you dont need to install and calibrate a new crank trigger wheel with sensors and such, not multippel coils that look like 2020 and beyond. You dont need to g to a dyno session and make your own map. The idle and cold start system is tested from minus 15 degree celcius and up to +30 degree with a stabil idle level both in Neutral and drive. I have implemented fuel cut systems and it leans out or richens op at the correct driving modes fr better fuel effichensy.

What you need to do to install it is:

  • Before you take off anything you should check the Ignition advance acordingly to the innstallation manual. It should be std spec.
  • Remove old fuelrail and take off all injectors and old rubber hoses
  • Remove the old Idle air valve at the rear of the left head and mont the supplied blanking plate.
  • Remove the complete original injector harness.
  • Remove the ignition amplifier.
  • Remove all engine related vacuum lines. Ecept the one to the automatic transmission, brake booster and climate system.
  • Remove the original ecu in the trunk. Blank the rubber hose.
  • Install the new idle valve with the supplied hoses.
  • Adjust the throttles and tps accordingly to the installation manual.
  • Install the new injectors to the fuel rail with the hoses and clips supplied.
  • Place the new harness nicely into the engine and the ECU plug towards the Brake booster
  • Mount the fuelrail with its new injectos to the manifold with the new injector mounts supplied.
  • Mount the new air and water sensor where the old ones are at the left front of the engine.
  • Plug the harness into the distributor, idle valve, all injectors, tps sensor, coil, tacho wire, ign wire and temp sensors with the marked and terminated plugs on the harness.
  • connect the harness wire marked +12v to the battery and – engine ground to a screw on the inlet manifold.
  • Mount the new ECU on the supplied bracket that fits on the brakebooster and plug in the ECU harness connector.
  • Install the fuel pump wires on the harness to the fuel relay as describedin the installation manual.
  • Turn ignition on and check for fuel leaks when fuel pump stars for 5 sec.
  • Start up
  • Your idle should be 750-800 rpm when hot, 1100-1200 when cold.

The system has been tested for a long period both on the dyno, long trips and daily use in different conditions. the most difficoult is to calibrate the cold start systems and idle control. But Now I feel it is perfect and ready for most needs.

Dyno work with the new V12 EFI

The HP and Torque has been raised a bit and the testcar witch is a 1985 XJ12 with 100 000 km on the clock delivers 330 HP and 439 Nm on the engine with the popular Sport intake you find in the Jaguar Sport shop.
This made the car do 0-100Km/h in 6.1 sec and it has a fuel onsumption of 1.25 litres pr 10 km at variable contry road.

Find this kit with its options in the jaguar Sport shop here:
Email me if you have any questions about this please.

Best regards
Ole Martin Mobeck

    • Well, This exact kit you are looking at is not because it uses the P-Digital Lucas distributor. And its pre-programmed to the 5.3 HE.

      The 6 litre already has a pretty good system, (exept it still has that Idle air valve with the old technology).
      But since I have had many requests about doing a system for the 6 litre I am working on one now.
      It will include a new triggerwheel to mount behind the front damper where the original triggerwheel is.
      And two new coilpacks with total of 12 coils.
      But i dont know if I can make it pre-programmed as I need a car here to do it. I spend a lot of time to make the map as it is not only done on the dyno. I has to check and test the cold start systems on all temp’s from cold to hot, both air temp and egnine temp.

      But just follow this place and you will see whenthe new stuff is coming out.
      Also, by sending me an email at I can do custom systems for you.

      The system you see for sale here is for a std 5.3HE with P-Digital.

      Best regards
      Ole Mobeck

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