how do i diagnose a miss fire

[trickydicky]

i have descovered that a rumbling that i have had under load is a miss fire. i changed the cam belt the other week and notised that the valve cog is out by half a tooth.i have had the pump timing set. it has always started rough but the diesel bloke said he thinks that the valve timing is out has anybody got any advise or is there anything else it could be?

[trickydicky]

douse anybody know if i how likely it is that i will do damage if i advance the valve timing cog by one notch?

[extreme90]

take it all apart and start fresh,there are timing marks on all spockets to time the engine up

[trickydicky]

the timing marks dont line up whith the teeth on the belt it is always half a tooth out i was wondering if i should advance it by half a notch? at the moment its back by half a tooth(the cam sprockat) will i smash my valves in by trying it ? what do you think?

[Range Rover Blues]

If you don't get the valve timing right you'll do big damage.  If the pump timing is out you may get a strange coloured smoke (can't remeber the colour, sorry) but if it's retarded you get no powerm if it's advanced you'll get noisy deiseling and negative work, it won't damage anything in the short term other than your pocket but it's not a good idea to leave it.

However, why would incorrect timing affect one cylinder :-k

[trickydicky]

good point but when i changed the cam belt the cam sprocket was defenatly out by half a tooth when i put the new one on it was exactly the same i have changed the injectors and had the pump set by a pro and it still puffs if left to tickover for a wile. its not burning any oil,dousnt have much power but i have only ever drove this one so i wouldnt know ,i only know what peaple have said about the 19j 2.5td. do you have any idiers. it defenatly smokes and rumbles when you boot it in the higher gears if you take your foot of the acselerator it stops. and thats only when the engine is pulling it flew through the imishions on its MOT last week so thats the only thing i can think of that perhaps the valve timing is slightly out like the diesel mechanic said.