Engine turns - does not fire. No fuel supply for some reason. No previous problems, And no signs of this problem until it happened. What could be the likely cause?? Car is Renault Laguna Expression 1.9 Diesel (03 model)

the reason of tapping could be:
a) a low quality gasoline with low octane rating below 98/95
b) wrong adjustment of carburetor
c) valves need adjustment
d) high mileage on the engine

you didnt stated the symptoms correctly

it either cranks or it does not.
that means the starter ACTUALLY turns the cranks shaft over
robustly.
the crank shaft damper pulley is the clue to this , it turns or not.
if it always turns this is a :
cranks ok but wont start.
so, that means tune up the engine,
1: low battery voltage (slow cranks)
2: never tuned up this decade?.
3: bad fuel.
4: weak spark at any of the spark plugs, sure all must be good.
5: flooding, (wet spark tips)
6: fuel starvation.
7: any of 50 other engine mech. issues,(burned valves, is 1)

If the engine is an indirect injection, glow plugs will be necessary for starting.
A fairly reliable quick check can be made with specialised test equipment but nearly as good, if everything else on the engine and fuel system is in good order, is to disconnect the intake hose and provide a supply of hot air directly into the intake and the engine will quickly spring into life.

Personally I doubt that will happen and the result could be the engine will stagger into life.

Considering the age, I expect many things will be slightly below peak efficiency. The all-important compressions are likely to be less than perfect which means even if everything else is good the cranking speed needs to be as good as it can be, which it probably isn't.
The fuel pump is likely to be showing signs of age and allowing a certain amount of overnight fuel drain-back and be slower to recover. The fuel pipework is probably not leaking fuel but might be allowing some air to be drawn in. I once had a bad starting engine and the cause was a defective canister-type fuel filter allowing air into the system.

Experience has taught me it is best to give such a vehicle a proper birthday and to ensure what can be done at a reasonable cost, is done.
What must never be forgotten, that is fundamental to good starting, though the cost isn't reasonable, is the injector break-off pressures and spray patterns - no birthday will be complete until these have been removed and checked.

check your fuel pressure it should be 55-61 psi with key on engine off.It should have a fitting on the fuel rail to hook a gauge up to.If below specs replace pump.

Sounds like a fuel supply problem. Does it pop through the carberator as it it is dying, like a lean back fire? If you drove it up a hill would it die before 35 or 40 mph? If the fuel demand excedes the fuel supply the engine will die, but would restart after cranking the engine for awhile. Possibly a plugged fuel filter, fuel line, rotten fuel hose, ( sucking air ) or tired fuel pump. Hope this helps.

Hi.

A failed start can happen for a number of reasons. If this happened just once, it should not be reason for concern.

If the problem happens again, the first test you can do to locate the problem is an OBDII code scanning.

The scan can be done at any local garage. If you purchase a scanner like the ones linked below you can read the codes by yourself.

OBD-II-Scan/dp/B001LHVOVK

OBD2-Trouble-Code-Reader-Scanner

The connector is located under the dash.

Once you have the codes you can get back to us for an explanation. Here you can also find basic info on OBD codes.

If the problem happens regularly, then other test that must be done is checking fuel and vacuum pressure using a Vacuum and Fuel Pump Tester. This is a gauge that must be placed in between the lines to read pressure.
By reading fuel pressure it is possible to spot problems caused by blockage, fuel pump malfunction and problems with fuel pump aeration.
By reading pressure on vacuum lines whilst heating the lines with an hand torch (this must be done by a mechanic), you can find vacuum leaks.

Engine shut down can be caused by a number of reasons. Among possible causes misfire, rich or lean mixture, air intake blockage, MAF or AIT sensor problem, fuel circulation problem, vacuum problem, fuel tank cap not allowing air in, electronic injection problems.

If you get the problem again, read codes and replace spark plugs, air filter and fuel filter.

Regards.

I will fist need to know if engine just died,this happened over night it ran out of fuel? it it ran out of fuel you will need to prime the fuel system of air witch may include loosening the fuel injector lines and cranking engine over then when engine starts to fire tighten lines and continue to try until it starts it will run rough and smoke white and then it will clear and be back to normal. it can also be a bad lift/fuel pump or a cracked or broken line,bad injection pump many things just need more info message me if any more questions thanks and good luck

Check the fuel lines, fuel filter, what is the mileage? If it is high than it might a sign of injector pump or injectors.

Ok, so you drive along & without any warning your engine cuts and you coast to the roadside. After a short time, you are able to fire it up and continue until next time. From the decription you supply I have to decide whether the problem is caused by lack of fuel, or no spark. Can you expand on what exactly happens here. Is there any sign of a miss, or loss of power prior to this happening. Anything you can think of will help

You may have a fuel pump issue, or as you mentioned a fuel problem due to water or old gas, check the pressure at the fuel rail that goes to the injectors, there is a service port there, also take a sample of the gas and let it stand to see if any water is present, smell the gas, bad gas smells like paint thinner.