www.jec.org.uk

Thursday night - went to Cov & Hinkley monthly meeting in Aristocat (I call it a Jaguar - it has components from about 17 dead jags). Good evening, but due to my own inattention got a double flash from a Gatso on the way home.

Friday morning - finally got the XJS off axle stands after replacing front subframe (passed MOT test the same day I found major corrosion); did new springs, new joints new bushes at the same time. Cycled to local PO to tax (never mind the environment, I can never find anywhere to park there). Plastic card declined at counter - great embarressment - had to go to local hole in wall and get cash with the same card.

Wife decided we should visit son plus girlfriend in Birmingham (no real problem, but I'm not quite PC enough for art student girlfriend) so off we go.
Just after going through Queensway underpass a middle aged lady - ie younger than me - decides to rapidly change lane totally ignoring the green XJS on her near side; sod it, over 50 and raised cholesterol I can have a heart attack all on my own without any help from fellow motorists.

Passable meal at Birmingham Italian, I hardly upset the girl friend at all, then wife and I decide to head for home.
IT WOULD NOT START.
Q. What's wrong ?
A. How the hell do I know.
Q. Is it something you've done?
A. Probably.
Q. Shouln't we have come in a more reliable car?
A. XXXXXXX

Finally got it to start with multiple pretty lights and engine fault warnings and actually had an uneventful trip home, with the exeption of a non-functioning tachometer (been playing up for a bit).

Today, after wiggling the contacts to the ECU, air meter and and cleaning the contacts to the ignition amplifier (FF 24), in other words, spending 2 hours doing nothing meaningful other than replacing the damaged resistor in the negative feed from the coil which was causing the tacho. failure, all is back to normal.

Did the blasted thing know that I spent £170 on a tax disc the same morning ?

Robin

What engine and year is it Robin? It sounds like a very similar problem that I had when the crankshaft sender failed.
Pop

She's a late 1991 4.0 - one of the earliest post-facelift models.

Most of the time I'm in awe and wonder of electronic ignition and computer controlled fuel injection, and will readily concede that their reliabilty and effenciency compared with antiquated things such as carburettors and contact breakers are of an order of magnitude; however, when it let's you down one is less likely to be able to open the bonnet, fiddle with something and drive home with dirty fingers and admiring smiles from the passenger seat.
I'm probably looking at a session with a diagnostic computor in the end; but I know that a). I will be charged b). I am bound to be given a long list of sub-performing sensors, controllers and wizgits.

My real sense of frustration is not the problem, but the fact that the car is - touch wood - at the moment again behaving impeccably when all I did was clean some contacts, wiggle others and stare at all the wires going into the ECU. The scientific me says that there is an intermittant faulty component, but the visceral me believes there is a demonic entity in electronic systems.

Sorry, Pop, didn't mean to go on, and I will keep the crankshaft sender high on the suspect list if I have any more problems.

Robin

We had a similar problem on a 4.0ltr saloon with intermittant fault like yours. Then the problem got worse and we couldnt get her started for 3 days. Went out to try to start her after nightfall and opened the bonnet for a look see. When she cranked over there was an array of small sparks between the plug leads where the bunch together. Replaced the distributer cap and leads and havent had a problem since. Also have noticed an improvement in mpg since. Check it out and let me know if it helps D x

Thanks for that; I'm doing to do that out of curiousity (think I'd best not hold the leads at the same time), but to be honest, she has taken such an affront to me vilifieing her in the forum that she has not missed a beat since, including a 650 mile round trip this weekend to Cornwall. If it aint broke dont mend it ?
All the best,
Robin Gripp