My GL1100A sounds like a thrashing machine when it starts. The oil light goes out when the engine is running. Is it likley that the oil pump has failed

Oil pressure must be checked with an external gauge that you connect to the same point as the oil pressure sending unit. With the engine at normal operating temperature (hot after 30 min spin), at 2500 rpm or above, oil pressure should be above 20 PSI up to around 30 PSI. It may go as low as 5 PSI on idle with a hot engine but should increase as soon as motor comes off idle. Oil viscosity and ambient temperature will affect oil pressure. If your experiencing this problem only with a hot engine, you may have a big problem in the timing chest. Inner cam bearings are known to collapse (these are smaller than 2007 MY) and the rollers enter the oil pump, thrashing it and causing low oil pressure. If the external gauge (use one that goes to 60 PSI or there abouts) shows correct pressures, then your sender unit, wiring or gauge is faulty. Check this as soon as possible as I have seen engines completely thrashed over this. Ruined engine cases (cam bearing completely disintegrates and cam shaft starts running on parent metal), big ends gone, pistons and barrels, oil pump and cam plate, tappet followers, the list goes on and on. On one engine I have done, I was only able to use the cylinder heads, push rods and covers. Everything else I had to replace. If you find this bearing damaged, make sure that the oil pan is removed and washed out as rollers are picked up by the scavenge side of oil pump and 'pumped' to oil pan, ruining oil pump in the process, sucked back to oil pump and screwing the pressure side, damaging the cam plate, and on and on.

My truck Hino dutro year 2005 is on check engine light, coputer say this fault, p2002 particulate trap efficiency below threshold (bank 1) now i dont know what is this fault Plz send me detail for this fault and solution.

A gearbox will not "knock" in the usual sense, that is said of an engine running on petrol which is a lower octane than it needs. The sound is more of a light rattle or pinging.

If your manual gearbox has had the wrong oil in it for only a week or 2 and has not been thrashed, it is unlikely it has been damaged at all. Just drain and refill with the right grade.

If an auto gearbox, using the wrong oil can cause damage, as it may be far too thick. Drain and refill 2-3 times with the correct grade, running the engine until warm, but not driving around, in between. Then go for a drive without thrashing the car, and see if you can notice anything abnormal.

If you can, take it to an auto trans shop for advice.
Then

LOW OIL PRESSURE WILL CAUSE OIL PRESSURE SWITCH OR SENDING UNIT TO DISABLE FUEL PUMP.CHECK FOR OIL PRESSURE.REMOVE OIL PRESSURE SENDING UNIT SCREW IN OIL PRESSURE GAUGE TESTER INTO BLOCK WHERE OIL PRESSURE SENDING UNIT GOES TURN ENGINE OVER CHECK FOR OIL PRESSURE SHOULD BE 18 PSI @ 2000 RPM. BESURE TO WRAP TEFLON PLUMBERS TAPE AROUND THREADS TO THE OIL GAUGE PRESSURE TESTER OIL WILL SPRAY EVERY WHERE.IF YOU ARE GETTING NO OIL PRESSURE.YOUR OIL PUMP FAULTY.YOUR ENGINE CRANKSHAFT BEARINGS WORN OUT.WORN DAMAGED CAMSHAFT OIL PUMP DRIVE GEAR OR OIL PUMP DRIVE ROD DAMAGED OR BROKEN. IF OIL PRESSURE OKAY OIL PRESSURE SENDING UNIT IS BAD.

sounds like a problem with your oil pump

It is normal for the light to be lit if the key is on and the engine is off, it comes on when there is no oil pressure and since the engine is not running there is no oil pressure. When you say "wont start" do you mean cranks over but wont run or when you turn the key nothing happens, or you turn the key and ther is a click but that's it These conditions are very diffeant and the diagnosis will take an entirely differant path depending on which it is. Give a few more details and try your post again. If it cranks but won't start the most likley cause is the fuel pump.

check your fuel regalater sounds like you are getting to much pressure ot the injectors

first check the oil level if its good then change the oil if you hav'nt done so all ready and add some LUCAS oil stablizer this may help alot if not then the oil pump is most likley going bad and needs to be replced before the engine lacks oil and cause the engine to seize.

Here goes:
Please do not drive the car.
Have the car towed to a well-recommended garage
Have someone unscrew the oil pressure light or gauge sending unit in the engine block and screw is a oil pressure guage ( hand held, used in garages).
Test that pressure carefully at all speeds.
Either you have: a bad oil pump, a plugged oil filter, a clogged oil passageway, or a bad engine.
The ticking sound might be valve lifters that are not receiving oil.
God bless your efforts.

This is most likely a sending unit problem or a poor ground to the guage, try the sender first.