Won’t start

[MaxTheDog]

Hi All,
I appreciate this could easily be a ‘how long is that piece of string’ thing but here goes.
The Jaguar has just come back from almost 3 weeks at the body shop getting stuff sorted. Went to pick it up and drove home with no issues. Next day needed to move it slightly and it wouldn’t start. It cranked but wouldn’t catch properly and stalled before the majority of the dash lists had gone out. I hadn’t used it much before the Bodyshop so I put the CTEK on it, but the battery is less than a year old. The short amount of time (2-3secs) that the engine was running it sounded rough and ‘lumpy’. I had an instance a few weeks back where it wouldn’t even crank but after a few attempts fired up and has been perfect ever since. Could it be fuel gone off (premium every time)? I’m going to try it again after the CTEK’s been connected a couple of days. Any ideas or pointers would be appreciated.
Cheers,
Michael.

[mike020150]

Wow, that's "a long piece of string"! Assuming it doesn't start after the battery has been topped up, I'd recommend going back to the basics to check for a spark and fuel at the engine. From your description of a period of time without running, I'd begin by listening to hear if the the fuel pump runs during cranking, followed, if necessary, by checking for fuel pressure under bonnet, and that the fuel cut-off switch (inside the car) hasn't been accidentally activated. Fuel pump failures are practically endemic on XK8s after winter lay-offs. Even modern fuels don't deteriorate as far as non-starting after only a couple of months or so. Mike.

[MaxTheDog]

Thanks Mike for your reply.
Well since I posted a bit has happened to possibly eliminate some things and muddy the waters of other things…
On Monday it had a 80 mile run up and down the A1. Started perfectly first time!
On Wednesday tried it and coughed and spluttered but eventually fired up, revving at about 1200, which fell to around 750 and stayed there.
Checked the OBD:
P1111, P0172, P0175. Two too rich a mixture and an intake temp. sensor voltage too high.
Yesterday - started perfectly.
Today, coughed and spluttered but eventually fired up with varying revs - 900-1200ish. However on the dash we’re TRAC not available, ASC not available, engine in restricted performance, and gearbox fault! On the OBD I had P1000 and P1121. Throttle sensor intermittent high voltage my common one P1000. Turned ignition off, started and all the dash messages had gone and the OBD’s were down to just P1000.
Plan of action - do a service maybe even replace the fuel pump/filter, clean the MAF and the throttle body. And use it!!
Battery volts when engine is running 14.3V, 12.8V when not running. Actually the battery is 12 months old at the end of this month.
Any thoughts would be appreciated.
Regards,
Michael.

[mike020150]

Simple is beautiful in the engineering world. As mentioned previously, I think starting with the basics has to be a good idea and a good service is a fine beginning. Under some circumstances, the lamps and codes listed can be misleading. E.g. a dodgy spark plug (when were they last changed?) or a failing coil pack or two could make the car so difficult to start that battery voltage drops low enough to trigger spurious lamp warnings and codes. A measurement of fuel pressure as the car is started would help to confirm or eliminate a problem in that area too. Mike.

[JimMann]

The low voltage spike during the starting process could also be caused by a bad earth connection, which is "good" intermittently, thereby giving the same symptoms as a dying battery.
Jim Mann

[BrizzleJag]

Like you say a very long piece of string, what I would say is don't delete those codes with your OBD II reader. If you end up having to take it in to a Jaguar Specialist they will need to see the fault code trail to properly diagnose it.

[MaxTheDog]

Thank you all for your replies.
Mike - regarding the spark plugs, I don’t know and will have to get the folder out to see, but I’ve had it since September 21 it’s done about 5k miles since then mostly on shorter journeys so they could do with a change methinks. They certainly weren’t done just before I took ownership.
Jim, I’ve checked the battery terminals and the earth strap in the boot. Is there anywhere else to check?
BrizzleJag, good idea, I save each ‘read’ as a screenshot.
Nevertheless, a service - oil and air filters, new fuel filter, new plugs, maybe a new fuel pump won’t do any harm, I’ve just done all filters and fluids on my Freelander. In the meantime cleaning of the MAF and throttle body vane and associated pipes will be done while waiting for the service bits. I’ll have to buy a set of feeler gauges!
Cheers,
Michael.

[JimMann]

There are earth straps under the bonnet on the X-100 model, making the circuit between the engine and the body.
Jim

[MaxTheDog]

Thanks Jim,
I’ll check them although it’s started perfectly first time the last three days….
Regards,
Michael.

[JimMann]

Cheers Michael, still sounding like an intermittent fault and a poor earth connection that comes and goes would fit that bill.
Jim