Xjs V12 Timing

[kvalidir]

Hi, Have a Jaguar XJS 5.3 V12 G registered bought not starting. Brothers did all of the usual spark, fresh fuel etc etc etc, everyone concerned decided the timing was out. Fair enough, they have now gone to time it and there are no timing marks whatsoever. Been told to remove #1 sparkplug and get the point where #1 piston is uppermost and take TDC from that then plumbline the pully and set the timing to 10 degrees before that to start it. Does anyone know if that's correct please? Quite a car savvy family but never come across no timing marks whatsoever before. Ta muchly xxx

[pauln90]

Try youtube

[kvalidir]

Thank you both so much that seems to bear out what we've been told.
No I bought it as a non runner. Allegedly it was driven into the guy's garage left for about 2 years and then wouldn't start when he wanted to move it but how true that is I honestly don't know. It's a genuine 45,000 miles on it though with paperwork to back it up so I'm hoping it's the truth. Aside from it not starting it's immaculate, very solid underneath, and free rolling which is more than my brother's coupe version was ( he had to do the horror back brakes on his by dropping the rear end), so hoping that's not necessary but I have to get it started first before we can really judge much else. I'll mention the 180 deg out thing to him.
I've shown your video to my brother whose outside swearing at it now. I'll let you know how we get on. Thank you both so much:)

[The Builder]

That 180 degree thing .......... you should be able to tell by taking off the cam covers and watching the valves.

That way you can tell if you are at TDC on the firing phase rather than the exhaust phase.

[kvalidir]

Thank you Builder- I've told him and he's got the cam covers off already so hopefully tomorrow it will zang into life ( I'm such an optimist). I'm just flaberghasted anyone would make something so flaming awkward and loathesome to work on.

[The Builder]

Haha ....... the other thing is ............ do you know for sure which bank of cylinders has piston number one. Obviously it's the front one on an inline engine. I don't know which it is on a V

[The Builder]

Hey Methyl. Thanks for that. It's been a long time since playing around with a V engine. A V8 Chevrolet Camaro in my case :o)))

[kvalidir]

It's certainly proving interesting lol. He's called it a day for tonight and now I'm being harassed for a take away, which seems pretty fair to me. I have no idea how he identified which was #1 but I'll give you an update tomorrow and let you know. Thanks you all so much for your help:)

[MantaRay]

If the vehicle has been standing some time then it's quite possible the fuel pump has failed. Check this by trying to start the engine with Start Pilot or Easy Start, it's a quick and easy way to eliminate an ignition problem. This method has helped me on numerous non-starting [or difficult starting] cars many times in the past.

[dougielogan]

If the car has been laid up for a couple of years the pe5rol could be off.

[kvalidir]

Thank you Mantaray & Dougie.
We flushed the tank and ensured that it's receiving fuel properly and firing already, which is why we turned to timing it. Not much been done to it today but tomorrow is another day :)

Thank you all:)

[kvalidir]

Hi, quick update. Horror of horrors the timing is right and it's STILL not starting. We're waiting for a crank sensor to arrive at the moment. Meanwhile does anyone else have any other ideas please( however obscure) because we're stumped now? :( Thanks:)

[MantaRay]

Don't forget to try Easy Start, at least if the ignition is working you will get a hint that the engine is trying to fire up. I had an XJS with the same problem, turned out there was insufficient cold start enrichment for an initial cold start on the V12. If you do use Easy Start, follow the instructions on the can and don't spray it into the intake while cranking the engine. Try a few seconds spray into each air filter snorkel then crank the engine.

[kvalidir]

Hi Manta, we've tried that- it won't fire on Easy Start either but thank you for the suggestion. We are all really stumped:(

[Graham-W]

I presume you've got the firing order right.
Firing order is 1a 6b 5a 2b 3a 4b 6a 1b 2a 5b 4a 3b (anticlockwise)
a is LH bank
b is RH bank
If there is no spark at all try the coil by putting the HT lead near earth whist making and breaking the 12v supply to the coil. No spark=duff coil.

[kvalidir]

We'll double check that in the morning Graham, but last report from my brother just before it got dark was timing was right, spark and fuel present but not firing even on ether and he's utterly mystified. Thank you for taking the time with this, I'll get it all double checked in the morning:)

[MantaRay]

So, it has a spark, yet no signs of life with the Easy Start....Hmmmm...the plot thickens...will give it some more thought.