My XK8 won't start. On attempting to start it , it ran for about a second, dropped out on at least one cylinder, so I shut it off. Next attempt produced a "STABILITY SYSTEM FAULT" .I trickle charged my battery and tried again, it seems like the starter is engaging very slowly and not cranking quickly enough to start the engine. Almost like a depleted battery on its last legs. Has anybody else experienced this phenomenon? It has had the timing belt idler recall done.

 

That engine does not have a timing belt, but rather cam chains. My mechanic tells me that your symtom is a sure sign of cam chain tensioner failure. When the plastic in the original tensioners fail it typically happens under starting conditions when there is low oil pressure. Upon starting, the cam chain will jump time and engine will not start. I suggest...do not attempt to run engine...get it checked. Good luck.

 

My crankshaft is turning, though. I was under the impression that this is an interference engine and if the timing has slipped, the pistons will hit the valves and the engine will not be able to turn over. In essence seizing it up.

 

The pistons hit the valves and will bend them, but the crank will continue to be able to turn.

 

If the timing has slipped, how can you tell, apart from the fact it won't start? Can you observe anything through the plug holes, or any other way externally, without tearing into the engine?

 

Are you sure it is not really a bad battery? Has it been load tested?

 

Seems like two ways to go at the problem. Assume that the chain has jumped and pull the cam covers to verify without turning the engine over any more (safe mode). Or, check voltage at the battery, and then crank checking compression, fuel pressure, etc. to see why she won't start. (not so safe mode). My preference would be the first option. If pulling the cam covers reveals healthy looking chains and tensioners, then check the cam timing. If okay, then off to the races on the other possibilities. Otherwise, risk engine damage. It's a PIA to go that route, but better safe than sorry.

 

I turned engine over with ratchet on crank pulley and listened with stethoscope. No sign of piston contact with valves. However my engine stil turns very slowly on starter, not fast enough to start it seems. Also volt meter pulld down to 9vlts, could this be brushes?

 

Replace your battery.

 

Hi,
Mike 66 is correct, you may well have a dodgy battery, but remove the covers, check what tensioners are fitted, and check the timing. you have an early xk8 and even if you had no problem whatsoever, you should be checking the tensioners before using it any further.
I would think on average every week another XK8 self destructs due to failing tensioners rendering an otherwise fantastic car to the breakers yard.

your immediate problem is most probably a battery, even so it may not be the next time if you have old tensioners installed. Its a ticking time bomb.

Best Wishes

steveeasy

 

It's the battery. 9V is way too low for the electronics to function normally.

 

I forgot to mention that I did replace the battery and it still cranks over too slowly...

 

Check the battery main terminal junction box (arrowed in red) in the luggage compartment :



The cable connections are known to work loose. The battery cable to junction box can also deteriorate.

Graham

 

You need to look at the voltage on the battery posts during cranking. If that's OK, as Graham says, you've got a bad contact somewhere. Feel the crimp connectors to the main battery leads. If they get hot that's the problem.

 

9 volts will not start the car, take the battery to a shop and have it load tested and replace it if necessary. In your efforts to start your car you may have burnt up your starter. Now much has been said about both the battery and the tensioners and the only real way to know if they failed is to remove the valve cover and look. A compression test could help but at this point you do not know if you have cylinder washing and that could skew the test results. When your starter is turning is it that it is turning slow or it is turning the engine with no compression? Could you be confusing the engine turning with no compression as your starter problem? A no compression situation would produce a steady turning sound from the engine; a compression situation produces an up and down sound indicating a buildup of compression as it turns. Not sure I hit the mark on the compression sound. Can you do a video of the sound it is making and post it?