option 1: Fleebay and the usual suspects.
Yours must be the 6CU but you can also fit a 16CU. Just make sure it’s the right one for your engine (Cat /no Cat, compression ratio)
I suspect the variances are minor in most cases. Tweaks for various emissions standards, hi-compression/low compression, and such. The engine would probably run OK with any of them.
But…
Did the Series II cars ever use Lambda/feedback systems? A feedback ECU replacing a non-feedback ECU, or vice-versa, might not work too well
I imagine one could just retrofit O² sensors if a feedback ECU is used to a non-feedback engine? A neat upgrade.
On the vice-versa scenario one could negate the O² sensors, but not an optimal solution in my books.
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The early models used ‘D’ system fuel injection, Tony - which uses a trigger unit in the distributor…
This set-up is incompatible with any later digital ‘P’ system ECUs - and it is pertinent to clarify with the seller whether it is a ‘D’ or a ‘P’. The former has a trigger unit, an oblong piece fitted below the rotor.
The point here is that the trigger unit failure will imitate an ECU failure - but a replacement trigger unit in working order may be very difficult to source.
While diagnosing a fault is difficult at the best of times; identifying the ‘D’ set-up is simple - and will have some repercussions for further actions.
Generally; ECU faults are uncommon - and the sellers reasoning is very relevant. A failed trigger unit is in a different ball-park from a failed ECU - the latter, in one form or another, is readily available. And sometimes DIY repairable - which may or may not be the case for a trigger unit…
Again; the ‘D’ and ‘P’ ECUs are incompatible - and converting one set-up to the other is unknown territory…
just spoke to the owner, its been at the Jag Specialist over 6mths, had the Opus replaced,
they dont know, could be wiring
he is sort of stuck, had some lowball offers, as he said, if it was going he would want 3 times the price
luckily, it is nearby to me, so I can inspect it, I know the tech well, and I trained & worked as an electronics tech many aeons ago
apparently it is a very early model, and the tech hasnt had these issues before, so it must be a tricky one, the owner was complaining to me, but I told him the guy working on is the best there is, the bill$ are adding up
the car is rust free, mainly in very good condition, fairly low km, from a collector, was a goer
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There is a cryptic remark referring to UK/European ‘P’ - and Japan/Australia ‘D’, Tony…
…but whether that was temporary, and when, or if, changed - or what applied to US is not stated…
The main difference is that the trigger unit (‘D’) provides one trigger pulse to the ECU injectors per revolution. The ‘P’ is triggered from the coil neg to the ECU, nominally triggering injectors on each bank once every third pulse…
If it is ‘D’ it hasn’t an OPUS amplifier - so it is still important to find out whether you it’s a ‘D’ or ‘P’ before you start searching for an appropriate ECU…
In theory, with a ‘D’; if a trigger unit cannot be acquired, it should be possible to trick the ‘D’ ECU by giving it a ‘single pulse’ trigger from some other source. But the ‘D’ ECU will not work with a ‘P’ dist - and vice versa…
And for all we know; a PO may at one stage have ‘done something’ - outsmarting us all…
the owner was muttering about this, so thanks for your clarification.
when I go see the mechanic, I shall take notes of what you have said, so we can identify exactly what is what, even though I am familiar with both V12, electronics, and having worked on electronic ignition vehicles, I would be very reliant upon the learning of this esteemed group to get it going
the last non-goer I bought took 20+ hrs of electrical from me to get it roadworthy
(not a V12 Jag though!)