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I suspect the Ign Switch Electrical section 1st of all.
Then I suspect the Ballast Block thing on the side of the throttle tower, or should be. They were unreliable when in the warranty period.
The OPUS Ign system, assuming is still is OPUS, is next on my suspects radar. Again, they were trouble from day one. All mine got the Crane XR700, if its still out there, and the AMP was located, by me, next to the EFI amp on the Rad support top panel.
Coil is sounding good, but what drives it is not playing friendly, and that will take time, lots of time, and patience to narrow down.
Fill the beer fridge, and sit and sort ONE system at a time.
Sadly, there is NO one fix that will sort it all, been there many times over the years.
That's why I be grumpy sometimes, the magic wand is dead.
Forgot, hence the edit.
Look carefully around the LH Engine mount. There should be 2 earth straps, engine to cradle, then cradle to chsssis, why, i\ts a Jag, nuff said. These are fickle at best, and I always delete them and run a dedicated earth cable, generic, from Engine to Chassis, and just because, I place one each side. That earth, or lack of, will drive you further into the beer fridge than you really should go, trust me.
Last edited by Grant Francis; May 24, 2024 at 06:05 AM.
It seems like there never is a silver bullet solution to anything in these cars except Coors. Terminals at the ballast resistor are clean but loose in the plastic housings. I will delete the housings and replace connectors as needed.
Ok the ignition switch has been cleared of old grease and reassembled. Also removed the plastic multi plugs from the resistor - one was definitely not making contact. No engine noises yet.
They are about as thick as your thumb, and OPEN WEAVE BRAID,
Look around, all over the underside. Someone may have fitted Generic cables, and used a better path, as I mentioned, If I have been in there one will be near the oil filter, the other near the starter motor, Blue in colour.
If in doubt, fit a cable, NEVER have too many Earth Cables on a V12.
Last edited by Grant Francis; May 26, 2024 at 02:14 AM.
Reason: my spelling sucks
Ground straps are RH side behind the catalytic converter heat shield. The end on the bellhousing is clean and tight but it turns green as it goes behind the shield. Are these held in place with rivets or screws? Also does the ignition amplifier need thermal paste where it contacts the fender. Thanks
Last edited by 1977XJ5.3; May 29, 2024 at 03:55 PM.
Earth cables should go Engine assembly TO a Chassis Ground point. I use the Chassis point at the rear bolt of the cradle to chassis "V" mount, easy to see, and get to. Any decent bolt on the engine/trans will suffice for that end.
If the Earth is suspect, and/or not good, the electrickery will find a path of sorts, such as Gear Select cable, Accelerator Cable, BOTH not good as they are nylon lined, oops.
I have always been to\aught, VERY firmly, that EARTHS are more important that +ve, and I stand by that today.
Thanks for everyone who has been helping out on this thread! Finally back on this project, also have a Lucas Fault Diagnosis PDF manual in the arsenal which covers the Opus ignition. One of the troubleshoot guides describes testing the .020" gap between the distributor pickup and the reluctor ring but I only have metal feeler gauges. Is there a better tool? Are the rings failure prone?
Also (asking out of pure optimism) if/ when the car is actually running, can these Opus ignitions survive light duty service? It seems like the supplies of xr700 systems are drying up. Thanks again
Drying up is putting it mildly. The 12 cylinder disc for the conversion appears to be unobtainium. I saw some talk from sometime back about teproing that part, but I don't think anything came of it.
My dealings with the Opus are short and swift, as mentioned earlier.
The ferrite strips in the plastic wheel fall out, gravity. So, a TSB was issued waaaaay back to remove that wheel, invert it, and apply a "drop" of glue to the opening for each rod, thus securing them. I heard Super Glue was the go to, but never did a hands on myself.
One of mine was a V11, and nothing made sense. Eventually found that had a dropped ferrite strip, duh.
HEAT, the killer of the Opus Amp in the "V", and there once was a kit to relocate it out of the "V", but that was a very long tome ago.
All those things led me to the Crane at the time. Anything available today would be more reliable than the Opus.
Short running, dunno, its still going to get HOT in there.
I remember the guys in the then Club with E Type V12's, and when going on a Club run, always had an ice pack extra in their drinks cooler. They would place that pack on the Opus Amp to cool it down when strife raised its head. Sine all them were on Historic Rego, modification were a serious Taboo, and big $$ penalties applied if caught. NOT so these days, thank goodness.
Well it has been a little while but the work is continuing. The hidden ground has been located, cleaned with a wire brush and dielectric goo, tightened. The strap itself looks very good, no trouble threading the bolt in.
