Or maybe whats really right about it. I just finished installing a XJS electronic fuel injection system on my Series 3. I'm done with Strombergs. Pretty straight forward, but it took a long time because I'd work on it 10 minutes at a time.
The guidance was provided by Roger Bywater (he wrote a book on the subject) and the final yet to be done bit is larger throttle bodies and an ECU programed for the flathead engines as opposed to the HE XJS engine. I learned in the process that this is what was originally intended for the Series 3 V12 car, a different injection system, the development of which went poorly and was abandoned. The Strombergs were the unintended backup plan.
I tried to keep the installation as stock as possible. The end result is stunning. More power (even with the standard throttle bodies and the HE programmed ECU, starts immediately even dead cold, no choke or spitting and coughing as it warms up. Considerably more driveable.


Very pleased with the result.

 

Looks amazing!
Huge congrats on the great job.
Mike

 

A beautiful installation!
I'm interested in the Roger Bywater book - which one provided the guidance (or was it Roger himself)?
Have you driven it enough to get an idea what the conversion has done for fuel economy?

 

Thanks. Roger's guide, actually a booklet, can be found at the AJ6 Engineering site: aj6 engineering | For the Jaguar enthusiast
I started with that, my original 5.3 liter, rebuilt not long ago to 9.5 compression ratio, a 1988 XJS engine that that had been irretrievably overheated and the need to pull the heads to correct a water leak. In the process i talked to Roger several times to clarify elements. I duplicated the XJS schematic, but found that there are circuits that are not necessary in this application. But no harm done.
I'm driving it, but economy evaluation is a bit premature. The 1988 V12 was a HE engine and has a premix chamber in the induction path in the head. I didn't use the XJS head, I don't think they are compatible in any case. So the ECU is not mapped for the configuration I have. But Roger can remap the fuel profile in the ECU to accommodate the flat head and compression ratio, and he is also building a set of throttle bodies of a slightly larger diameter that will also affect the mapping. So now just driving to make sure everything else works, and when I get the modified throttle bodies and ECU I'll install with a new TPS, air temp and water temp sensors. Then I can get serious about tuning the thing.

 

Wow, that's fantastic! I'm looking forward to doing an EFI conversion as well. I hope mine ends up looking even half as good as yours ❤️