Ignition problems is megasquirt the answer?

My 79 with opus ignition refuses to work, and I am considering using an aftermarket solution.

The easiest is probably the Crane xr 700 which looks like it is fairly simple to install, but I am not sure if that is the only problem with this car - which has not run at all since I bought it
So the other possibility is a megasquirt system to replace both the ignition and the fuel injection system.
Does anyone have experience with trying to convert to these new electrnics?

Megasquirt is if you are backfitting EFI: MegaJOLT is for doing EDIS.

Dear Steve,

Use the search function to do a search on “Megasquirt” for the v12.
See also the MSextra.com website at some of the past projects for Jag v12s.

It isn’t a five minute job but you will have full control over the fuel and spark.

kind regards
Marek

i use the Crane ignition XR700 ,single coil, been 23yrs NO problems, run up to 6500rpm ,will go 7000.

for fuel i use SDSEFI standalone ECU , works very well fully adjustable!

ron

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Steve,

You can read all about the Crane conversion at my website:

www.efsowell.us http://www.efsowell.us

Ed Sowell

Steve
Depends on what you want to do with your car.
If you just want to get it going then a replacement ignition system should do it.
If, on the other hand , you want to improve its performance and efficiency then the Megasquirt is the way to go.
It will get your XJS running under computer control which removes a lot of compromises the original Engineers had to accept because the technology simply didn’t exist.
But…the MS option is more work.
So this is your first decision.
Regards
Matt

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Presumably also has D Jetronic EFI? Others with similar cars might chime in
here, but I think that’s two good reasons to go the Megasquirt route. The
MAP sensor alone on the D Jet system is unreliable and challenging to
calibrate properly.

Another idea you might consider is updating to the 80’s OEM system, Lucas
CEI ignition and Digital P EFI. Both are FAR better than the earlier systems,
and easier to maintain today. And you probably could get all the stuff you
need pretty cheap. It’s not readily tunable, though, which would be a reason
to go with the Megasquirt. Also, most of the Digital P systems are mapped
for the H.E. engine; just how well they’d work for a pre-H.E. is a question for
Roger Bywater – but you could possibly send an ECU to him and he’d fix you
right up. Alternatively, you could seek the Digital P ECU for the pre-H.E.
which only existed for one year; might be a bit prized. And it’d be for a
higher-compression pre-H.E. than yours; again the question arises of
whether it’d need remapping.

Still another idea is to go whole hog and upgrade to the H.E. engine along
with the Lucas CEI and Digital P. They’re pretty cheap to come by, and
you’d get far better fuel economy. In stock form you might even get a bit
more performance, although if you plan on souping the engine up you’d want
to stay with the pre-H.E. because it’s got more racing potential.

– Kirbert

Yes it has D-Jetronic which I am worried about. Can the jaguar injectors re-used with megasquirt? How much does one of these systems run? I have looked at the site and it is rather confusing. Do these kit include everything needed?

I am considering just an ignition system as this is the lowest cost, but if it does not work I have wasted this investment.

I am curious about your comment on the racing potential of the pre-H.E.

Tell me more about the sdsefi. Is it a complete replacement or just the CPU. how costly is it. does id use jaguar injectors?

Perhaps the easiest way to understand Megasquirt is to look at the colour picture of the DB37 connector and understand what all of the components connected to the new ECU do. Most importantly, once you have understood the concept of adding a new trigger wheel to get a crank signal then the rest follows.

Megasquirt isn’t the answer to an ignition problem - it is a new ignition controller, new fuelling controller, new everything else controller. It is very flexible and can work with almost any hardware but that sadly means that the owner has to configure all of the settings and that means it will be an educational process to go through all of the electrical subsystems piece by piece.

Fortunately, you aren’t the first person to do this to a Jag v12 but you’d still have to add a couple of sensors, wire up a harness and most importantly get a consistent and good crank signal sorted out.

Adding any other ECU is almost as much work, but you have far less access to the settings. For example, you could simply take a working setup from Lucas, Marelli or Denso from another Jag v12 but no one will help you with altering any of the settings in the ECU.

Appended is a picture of a home made wiring harness. Whichever way you go, whatever you do, if you do your homework and treat it as a professional job then you’ll end up with a successful result.

kind regards
Marek

The H.E. combustion chamber results in very efficient burn but not very good
breathing because the exhaust valve sits in a pocket. Great for street use,
not so good for racing. The pre-H.E. has a flat head, very easy to do
performance mods on, better for high RPM use all around.

– Kirbert

peng , google SDSEFI.com, plenty of info about system, but like any aftermarket fuel/ignition you would have to make your own decisions!

there is a lot of reviews to mingle thru. i like my setup, altho its is comprised of two systems, one Crane ignition XR700, and the seperate sdsefi,
they now have both systems in one package, they will work with factory injectors, again the Pre-HE uses a larger flow injector, better for more power , while the HE was engineered for better MPG!

you can use almost any injector, because the ECU is adjustable to your needs!

pricing is on internet!

Ron

Then look no further than the Crane 700. See my write-up on how to do it.

Ed Sowell
www.efsowell.us

Agreed: likely THE best, and simplest retrofit ignition ever made.

15+ years on the one in my Rover: perfect as when it was installed.

i checked this out – the web site says it is only good for up to 8 cylinders!

An internal combustion engine needs fuel, air, compression, and a spark to run. What you need to do is figure out which you don’t have right now, not to start throwing parts at it.

I don’t think that’s what he was saying, Ed. He was saying that if he installs a
working ignition system and then the car still won’t run because the EFI
needs replacing, he’ll be upset because he should have gone with the
Megasquirt to begin with.

– Kirbert

He’s right, though, that it can be difficult to tell when the engine’s not running.
For example, the injectors won’t fire if they don’t get a signal from the ignition
system, so it’s hard to tell if the EFI is functional or not.

– Kirbert

Exactly, I have already wasted $300.00 buying an new magnetic pick-up for the opus ignition, but the old electronics is not producing a spark, probably because it is not tuned to the correct frequency. Until I have a spark I do not know if the efi will work. The problem with the new electronic ignition, the xr700, is that it is still using the old distributor, which may also have problems with the advance etc. although i think that it has been reconditioned - it is quite clean inside and there was no difficulty in removing the rotor or pick-up disk.

How much does performance improve with the megasquirt?

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like any type of engine modifications, tuning IS and always will BE tuning!!!jag interior 001.

SDS programmer pix 004