I NEED SOME THOUGHTS

[xj12-rob]

thanks guys, all good stuff, here's a few answers to the questions

ECU is checked and looks ok with no water ingress

throttle cable is good and working 100% to return position

with regard to the throotle body swap, this has to be done on a ramp, the other XJR is in the body shop on the floor and not driveable!!

XJR6 does have traction, i have not heard of the link to bad running though, will investigate

CPS should be ok, not checked, but i have a modified bracket fitted, the CPS was out and cleaned when this was fitted

Idle speed motor is swapped with a fresh one

all connections checked and appear to be ok

[xj12-rob]

Ok up date, after 6 hours on the black beast today , we have an improvement, all the throttle linkages have been pulled apart, checked, WD40'd and white greased within an inch of their lives, i have had the car running and forced it to ingest brake cleaner in an attempt to clean any remaining crud from the throttle body, result, i have a car that will tick over at 8/900 rpm, however once throttle load is applied and released the tickover now returns to the classic gummed up throttle body rpm of 1500, quick hard blip and it returns to 8/900, methinks that throttle body is coming off again and getting replaced, goodbye to another saturday lying on my back, i'm getting too old for this!!!

[iainm9438]

a mate had something similar with his 40 - turned out to be the connector to the fuel pump behind the boot carpet was burning out (bad connection) and the pump only ran 'properly' over 2K revs.
he only found this out after 2 fuel pumps, new fuel lines, filters etc, 1 new tank and various sensors etc (expensive) i was there when he was about to take the angle grinder to the car in temper when a customer walked in (who used to work for the AA) and suggested the plug / socket

[xj12-rob]

yep, burnt fuel pump connectors on a 40 is favourite on cars with a submerged in tank pump, i posted this one some time back, my problem is throttle body/linkage related, i'm 100% convinced now

[naki_k]

perseverance and process of elimination wins through again. well done rob

[david]

You found out the problem in the end as I knew you would. It is a massive job though; it only occured to me later that changing the throttle body on a supercharged car is a far bigger job than on a standard car. Still, when you're tearing around in it and enjoying all that performance, the hours and hours spent in peculiar, painful postions contorted under the thing will seem worth it! (I hope!!)

David

[xj12-rob]

David, how well you know me, we had our JEC regions BBQ today, ah ha thinks old git Jenner, nice day for a thrash in the Black Stealth Bomber, my excuse the the War Office "it needs some miles on it just to iron out the last faults", having not driven the thing in anger this year, today was a real gas, anything slightly slow, Vectras towing wobbly boxes, Tin Tents, old people in flat hats driving Micras, the tartan picnic rug brigade were all despatched with ease on a hot (VERY!!) run up the A1 to Edinburgh, needless to say I NEVER wnt over the 70 Occifer!!

[david]

Fantastic!!

[xj12-rob]

Fantastic!!

oh Yes!!