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My XJS came with a printed page describing this ecu upgrade but a search here and in google didn’t come up with anything. Does anyone know anything about these? Who made them are they an improvement, any issues with them?
Oh boy, repeatable stuff I have read for way too long, sorry if that upsets some people, too old now to take offence.
My time with these, too long, has deemed the 6CU as so-so in its performance and reliability.
The 16CU upgrade, ALONG with XJ40 throttle discs, NO AAV, NO balance pipe, NO emission junk, Efans, wakes the HE up something fierce.
Wiring age, mainly the EFI loom, Resistor pack plug, and general lack of maintaining by too many previous people, makes a dog of the car.
I have had no such issues as mentioned, ONCE I got ALL the age related items sorted properly,, NO patching etc, rewired 100% under the bonnet included.
All my HE cars have been the same, and see no issues with teh Jag stuff, just silly stuff that is well known, and documented, and in the 21st century easily sorted, such as the stupid coax wire to pin 18, bad design, and the root cause of many HE engine running issues, but everything else gets blamed, sad reality.
My PreHE S2 XJ12, 3CU, is still as made, and clocked over 650000kms, and still does as it was designed, no hissy stuff at all. Leaks oil (no rust), LOVES the fuel (so what its old and a V12), goes like stink (goodo, it was designed to RUN strong).
My Red HE took us twice around the OZ coast road, and that was 25000kms each time, and not a hiccup to be heard.
Lots of modern upgrades out there, granted, but this V12 is "old school" design, 1954 in fact, so it will only ever be what it is, and that is just fine really.
Nothing wrong with what you have, but I doubt it is any better than the 16CU in real life.
A few here went with the Wolf 3D, and had so-so success, but I know of 2 that are now back to 16CU.
If its running hot and strong" and is reliable, I would leave it alone, but as for knowledge on that system, I dont know.
Last edited by Grant Francis; 03-22-2019 at 08:42 AM.
Reason: spelling still sucks
Grant
So TRUE, so WISE, so brilliantly explained! I, like many here owe you much in getting our cars dead-right. Your common sense cuts through like sunshine through the morning mist - if such things as mist exist in Oz!
Not where I live Greg more like alcohol, and the coffee mist, HA.
I will, however, bottle some French/Pom mist, when I hand deliver that X300 Daimler Double Six to your door, just need those bloody numbers to line up, HAHAHA.
Last edited by Grant Francis; 03-23-2019 at 12:38 AM.
Did you get any software to be able to access the diagnostics? I have doubts about some of the claims made, it would be interesting to see what is inside the ECU.
Wiring age, mainly the EFI loom, Resistor pack plug, and general lack of maintaining by too many previous people, makes a dog of the car.
Over the years I'm sure many V12 owners thought "I guess this is as good as it gets" and shrugged it off.....without realizing that the engine was performing at a sub-par level due to eventual and inevitable degradation of the various sub-systems
I sent my ECU over to AJ6 because when I converted it to a 5sp manual it stalled between shifts . Roger said something about the "fuel overide" or something like that had to be reworked to the ECU. Anyway AJ6 remedied the stalling between shifts. Did it give me more performance ? I don't know with the 5sp & 3.54 diff changes at the time it's hard to pin point that one mod that stands out.
interesting subject for the JAG V12 engine management!
when i was building my 1978 XJS i had no internet much less a computer! 1993/94.
i read about a guy in Calgary Canada, called him and told what i was doing, and the early bosch was not connecting in my Brain!
it was a new company and he had moved from GM Delco to manage electronic department , and was interested in my project!
he hand built this computer for me, and as time whent by he sent some upgrades for the system, final upgrade 10yrs later, he said send the whole computer back and he put a completly new chassis and box!
using my same plugs! all NO charge, i pay shipping!
well been 25 yrs and it still fires and runs very well, i find the most useful is adjustable when driving ,rich or lean at a finger away!
yes, may not be what can be had today like M/S Megasquirt stuff, or MOTEC .etc. control center hand held control ECU
SDSEFI.com still available but original owner retired, so i donno who , some one said they dont do V12 anymore?
they do have some stuff on line , in old days i had to use a telephone,DUH! now SDSEFI.com
ron
I see you never got a specific answer. This enhanced 16CU was some sort of re-design offered by Prestige Spares in Au back when they had a website that was less e-Bay oriented. I guess they were competing with Roger's Enhancements offering a local option for those down under. I don't know what happened to the company. They still exist. They may have changed hands. I'd love to know more about this thing just as a historical footnote.
This is the web-archive page from back when they *clearly* offered this product. I don't know if they still do by request or not. I speculate that a for Zytek engineer may have re-jiggered the 16CU as they were partnered with Jag during the pre JagSports years for the TWR XJRS and did quite a bit of modifications to the 16CU during that time. Note that Zytek employed triple injection feature (injection pulse split into 3 sprays) called "EM3" during I believe the JagSport years R1 ECMs - also on Bentley and Aston ECMS. .
Oh boy, repeatable stuff I have read for way too long, sorry if that upsets some people, too old now to take offence.
My time with these, too long, has deemed the 6CU as so-so in its performance and reliability.
The 16CU upgrade, ALONG with XJ40 throttle discs, NO AAV, NO balance pipe, NO emission junk, Efans, wakes the HE up something fierce.
Wiring age, mainly the EFI loom, Resistor pack plug, and general lack of maintaining by too many previous people, makes a dog of the car.
I have had no such issues as mentioned, ONCE I got ALL the age related items sorted properly,, NO patching etc, rewired 100% under the bonnet included.
All my HE cars have been the same, and see no issues with teh Jag stuff, just silly stuff that is well known, and documented, and in the 21st century easily sorted, such as the stupid coax wire to pin 18, bad design, and the root cause of many HE engine running issues, but everything else gets blamed, sad reality.
My PreHE S2 XJ12, 3CU, is still as made, and clocked over 650000kms, and still does as it was designed, no hissy stuff at all. Leaks oil (no rust), LOVES the fuel (so what its old and a V12), goes like stink (goodo, it was designed to RUN strong).
My Red HE took us twice around the OZ coast road, and that was 25000kms each time, and not a hiccup to be heard.
Lots of modern upgrades out there, granted, but this V12 is "old school" design, 1954 in fact, so it will only ever be what it is, and that is just fine really.
Nothing wrong with what you have, but I doubt it is any better than the 16CU in real life.
A few here went with the Wolf 3D, and had so-so success, but I know of 2 that are now back to 16CU.
If its running hot and strong" and is reliable, I would leave it alone, but as for knowledge on that system, I dont know.
where / how do you ID the existing ECU in my 84 XJS ....?
doing the ECU upgrade is my next project .. may take a while to fit in though .... twin thermos and complete cooling system renewal done some time ago as per Grants Spec ... made the new injector harness (myself) as well .... electricery has never really been my thing so a bit more homework to do before i do the upgrade ... need to finish the rear susp o haul first ....!
03-22-2019, 05:05 AM
