'96 Jaguar 6.0 V-12 w/EDIS

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'96 Jaguar 6.0 V-12 w/EDIS

Post by v12pilot » Mon Oct 19, 2009 8:20 pm

Hello fellow British (and especially Jaguar V-12) car enthusiasts!

I'm in the process of installing a V-12 from a '96 Jaguar XJ12 into my '84 XJS.

The XJS 5.3 is completely original.

AFIK the '96 XJ12 is the only production V-12 to utilize both EDIS and a Nippondenso EMS.

Both Philip and Ross' have been very successful in installing MS into their XJS' and the info that I've read from both has been very helpful (overwhelming positive) in my decision to go with MS.

Unlike Ross, I am going to utilize MS for both fuel and ignition, as my '96 is already set up for EDIS (I considered retro-fitting a Marelli ignition control, though the block does not have the provisions to drive a distributor (drive gear, jack-shaft, etc..) and it's obvious that the MS will do a much better job of managing the demands of the 6.0 ignition system.

I have a spare (and complete) '91 Marelli 5.3 and I also have the original Lucas Digital P 5.3 (w/upgraded 16CU ECU) presently running in the car.

Comparing both the Lucas and the Marelli to the Nippondenso systems the obvious differences are 1). The 6.0 Nippondenso has no distributor (as noted above) and in its place are two EDIS coil packs, 2). The Denso receives it's engine speed and cam position from sensors mounted on the flywheel and the A-bank camshaft, respectively. and 3), The Denso utilizes (2) IAC (Idle Air Control Valves (stepper type); One for the A-bank, and one for B-bank (both IAC's also have coolant pipes running into them), though I could run a standard 5.3 IAC cross-over pipe, thereby eliminating one of the IAC's, if necessary. 4), both a A bank and B bank have a individual MAP sensor on each intake manifold. The '96 also has a electro-pressure sensor on the power-steering hose to assist in low speed/RPM idle stabilization.

I will be converting to a TH700R4 (and possibly going to a 4L80E in the future).

With all of that in mind, what MS components (Already assembled) would you suggest to get started? MSII with ? I'll most likely buy the MS relay board in order to keep my time in wiring/soldering, and frying something really important to a minimum. I have everything from the '96 motor (wiring harness, sensors, injectors, coil packs, etc..) as well as the JHTD parts and service manuals for both the '84 XJS and the '96 XJ12. I can provide whatever OEM Jaguar parts and information needed

Your suggestions and assistance will be greatly appreciated, and I especially look forward to hearing from Philip and Ross!

Thanks in advance, and Best regards,


San Diego, CA

Note: I work in the auto-recycling industry and can acquire ANY OEM part for practically any car (Especially Jaguar) at little to no cost to me (this helps when doing experimental R&D :). I'm more than happy to assist other Jaguar V-12/MS kooks (oops, "enthusiasts" ;) ) in procuring what they might need as my personal time and "real job" allows.

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Re: '96 Jaguar 6.0 V-12 w/EDIS

Post by CHRIS211083 » Sun Nov 01, 2009 4:54 am

HI, this sounds great! i own a 1989 xjr-s 6.0 v12 (twr) and might in the future need to upgrade my ecu and was thinking of useing the ms. good luck with the project!!!

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Re: '96 Jaguar 6.0 V-12 w/EDIS

Post by macaddict » Thu Nov 05, 2009 2:11 am


Sounds like an awesome project, it's nice to know there are more people out there crazy enough to own a V12 Jag and try to Megasquirt it! I think the 6.0 HE V12 in the 1995-1996 XJ12 was indeed the only version of the Jaguar V12 to receive EDIS, I actually wanted to find one of these to drop into my XJ-S before I decided to go the Megasquirt route. I ended up trying to keep things looking as original as possible so I wouldn't have trouble getting the car smogged in CA, hence the stock Lucas CEI ignition.

With the wasted-spark EDIS system on the new engine you'll be able to virtually duplicate Philip's design, his setup is probably the most elegant way of pulling off EDIS on a Jag V12 and doesn't appear to require any changes to the MS-II software if you use the 36-1 crank-mounted trigger wheel. The ignition coil packs on the 1996 6.0 appear to be stock Ford units, so a pair of EDIS modules should be able to drive them without a problem. You might want to install the balance pipe if you're going to use the single MS-II internal MAP sensor, it'll provide a convenient tap point for the sensor and will help correct any slight balance issues between the throttle bodies. Even with the balance pipe it took a few tries to synchronize the throttles on my XJ-S well enough that I didn't notice an imbalance just off idle.

The UDN2916LB stepper driver on the MS-II CPU board is probably capable of driving two IAC motors (up to 750 mA) if the winding resistance is high enough (>40 ohms) although I'm not sure if there are other limitations due to component placement and board design or if the motors will stay in sync and not cause balance issues. I don't think the MS-II code will do closed-loop idle control, but I'm not even bothering to do idle control with the MS-II and haven't had a problem. You may need to add an auxiliary air valve to keep the idle from dropping too much when the A/C compressor kicks in though. Did you have any clearance issues with the Sanden or Denso compressor on the 6.0 or did you swap in the A6 from the 5.3?

Each injector driver in the MS-II should be able to fire a bank of 6 injectors, just make sure you're using PWM to limit the drive current if they're peak and hold injectors. I also noticed the fuel delivery was more consistent with the 6.0 rail design if I alternated the firing of the banks and fired each bank twice per cycle. The MS-II supports dual VE tables to allow you to run an O2 sensor on each bank, but with the MS-II v3.57 you'd probably have to add a few external components to properly condition the signal from the second O2 sensor as there isn't a prototype area on the board. I still haven't bothered to add the second sensor as there isn't any measurable difference in AFR between the A and B banks when in closed loop using only the A-side O2 sensor, but I'm going to set that up the next time I have to pull the ECU out of the car.

Also, don't forget to hook up the TCC solenoid on the TH700-R4 or you might burn it up, there's no flow through the cooler circuit when in OD with the TCC disengaged.

Good luck with your project, let me know if you need anything! I'll upload the latest fuel maps I have for my engine, they won't be an exact match for your application but the general shape of the map should be close enough to get you started if you scale the values appropriately.


- Ross.
1984 Jaguar XJ-S HE (Rosie III) - Megasquirt-II v3.57 fuel+spark

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