How hard is replacing an XJ V12 series 2 engine by a series 3 HE?

XJ
21

Bad 3cu ECU can be due to bad Elec. capacitors, open unit and replace them, thats what I did, all OK now

22

I didā€™nt purchase the car (and donā€™t plan to now that I know the issues I would be facing)
but to sumā€™up: the seller has installed an 1990 S3 engine on a 1975 S2 car without changing anything else (same 1975 ECU , original D-Jetronic ingnition, original sensors, harness, etc)
so not surprinsigly he managed to start the engine with spray in the air filters but it only runs for a half a second and dies.

23

@MarekH went that route, search for his posts, or search for ā€œstand alone ECUā€, ā€œaftermarket ECUā€ it has been discussed many times and there was a recent thread as well.

24
25

thanks Aristides
could not find it with these keywords- no worries

26

Indeed, Rolando - the ignition is an independent sub-system, requiring no ECU or external inputsā€¦:slight_smile:

Frank
xj6 85 Sov Europe (UK/NZ)

27

Thanks Frank, good thing

28

or

https://www.fome.tech/about

29

thanks Bill

I like the " If you want to get your hands dirty with engine management" , but in white gloves ?
I donā€™t believe that with my programming talents I would be capable of leading the way on such an innovative solution
maybe already tested by some forum users ?