After pump overhaul ,engine sounds differently.ie severe Knocking which reduces slightly on acceleration.Scanning done with Bosch KTS 570 and the results were (1) Error code P1121 .which could not be errased .What is the solution ?

SOUNDS LIKE YOU HAVE BEEN VERY BUSY,THE ONLY THING I CAN THINK OF TO CHECK WOULD BE THE EXHAUST FOR RESTRICTION (COLLASPED PIPE,MUFFLER ,CAT CONVERTER) HOPE THIS HELPS .LET ME KNOW.

Hello,
There is a possibility that the old motor was not burning properly and you have carbon build up on the O2 sensers. A poorly functioning O2 senser will not allow the Fuel/Air mixture to work as you give it gas under load. You could have multiple O2 sensers too.

SOUND'S LIKE YOU COULD HAVE A BAD ROD OR CRANK OR LIFTER.TRY THIS CHECK YOUR WATER AND OIL NOW START THE ENGINE IF IT IS A FAST KNOCKING HOLD YOUR FOOT ON THE BRAKE AND PUT THE CARE IN GEAR IF IT QUEITS YOU HAVE BAD ROD SERIOUS MOTOR REPAIR INTERNAL.DO THE SAME THING AGAIN AND IF IT IS MORE A THUMPING NOISE AND A SLOW DEEP KNOCK THEN WITH THE ENGINE IDLEING PUT IT IN GEAR HOLD THE BRAKE GIVE IT A LITTLE GAS AND IF THE MOTOR KNOCK'S GET'S QUEIT IT'S POSSIBLY THE CRANKSHAFT ANOTHER INTERNAL PROBLEM MOTOR OVERHAUL IF IT'S A FAST RATTLING IT'S PROBABLY A LIFTER STUCK OR BLEED DOWN DIRTY OIL OR A WEAK OIL PUMP ALL ARE BAD NEWS SORRY.GOOD LUCK

When you say the engine is hot are you talking about the normal operating temperature? Has the Check Engine or Service Engine light come? If so, was the On Board Diagnostics system checked for a codes? Usually a knocking sound during acceleration indicates a improper fuel mixture or low octane.

Oooops..sounds like you need an overhaul. Firstly, do not use this vehicle whatsoever. You will simply damage moving parts of the engine if you carry on using it. Get a mechanic to remove the Cylinder Head from the engine and inspect it for damaged Cylinder head gasket as the first step. Depending on the condition of the gasket, you will be able to tell whether its just a gasket replacement you need or ultimately, a Cylinder head reconditioning. I hope thats all you need. If not then you will probably need to remove the engine block from the chassis and inspect the crankshaft. For this, you will need to deliver the Engine block and cylinder head to a reputable Engineering machine shop near you. Good luck..!

Yes, I agree. Overhaul, or new engine time. Loud knocking indicates your crankshaft bearings are toast-it won't be long before a piston rod goes through the block, or the engine siezes up. Overhauling an engine with a bad knocking means a complete teardown and rebuild-very time-consuming, labor intensive, and very, very expensive. You might want to consider a used replacement engine with low miles as a cheaper alternative. Good luck.

when u put the fan on different speeds, does the noise change w the speed? maybe the fan itself?

That doesnt sound good. Check the engine oil level and top up as necessary. If the noise is still there, then you should take it to a mechanic to check. It could mean that you need to either replace the engine or overhaul it. Hope that helps

i would say your problem is in the timing

This sounds like severe engine damage, do to loss of internal lubrication (no oil). That's the bad thing about 'idiot' warning lights, they come on when u have a severe problem, and the damage is done. You are going to probably have to purchase a used engine from an auto salvage yard, or purchase a re -manufactured engine. Sorry for the bad news, this is about as bad as it gets.