4d56 mitsusibishi engine knocking. - Cars & Trucks

Could be injector timing issues. Too far retarded will give poor response and a knocking sound, a bit like the old Commer Knocker engines.

Not sure what you mean by opening the engine.

The combustion process of a diesel is not the smooth burn and increase in pressure of a petrol engine but is virtually an explosion causing a sudden rise in cylinder pressure. This is the source of the typical diesel knock and is more pronounced in some engines and some injection systems, especially when accelerating. It can be scary for those unfamiliar.
Electronic control tends to soften the noise.

Knocking might be the result of a mechanical problem (piston, connecting rod bearings, etc.) but if these things have been eliminated other causes of excess knocking can be excessive injection timing advance, dribbling injectors, bad spray patterns...

the switch should be in the radiator, but not sure

Hi, sounds like the cold start system has problems, like a choke on a petrol engine that hasn't shut off when the engine is hot. When you can see black smok coming out of a diesel exhaust it is unburnt fuel that you are seeing, there is a wire on the injector pump that controls the cold start on diesels, make sure it is connected to the solenoid on the pump.

I see that the engine is a Mitsibushi and suppose to be quite common. There are rebuilds and used engines on EbayUK.com.

Do a Browser search and you will find Repair manuals and possibly a Blog about this series.

Most of the knocks in an engine fall into several catagories. Lean fuel ratios and the failing of a knock sensor and poor fuel. The other catagory is excessive clearance in bearings in the crankshaft, camshaft, or rods.

You can buy an octane booster to add to the gas fuel, be careful if it is a Diesel. There are additives to raise the Cetane rating of Diesels too. If the noise leaves with the additives, you may have a bad "Knock" sensor or bad fuel.

Check your fuel pressure. If the pressure is weak, then the fuel charge is thin and then a "Knock" sensor can not adjust the problem away.

Over advanced timing. If the timing is too far advanced the engine can "Knock". You have to look at all mechanical components that affect timing.

There are varying intensities of a noise which leds to a diagnosis. It is something that has to be experienced and talking about it can not adequately express it. Try the few solutions I mentioned.

There is a website, Aboutautomobiles.com,which has a history of consumer complaints and resolutions by year, make, and model. You might find a clue there.

I hope my solution helps.

I suggest download this specific Factory Service Manual: Mitsubishi FSM Engine 4D56-25-diesel

Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

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It may be because one of the engine mount is broken

i think that is the engine code

4d56 is a diesel engine, fuel, oil, air filter change definitely, regular oil change, check tyre pressure, etc all basic things u can do yourself, after all its no 40+ MPG modern diesel engine its been around for years and years and being used in courier van, pajero and delica, i have a Delica with 4D56 turbo and its loves drinking diesel like no tomorrow, run it on veggie oil like i do you wont worry too much about your fuel consumption.

does the engine knock when you start to pull hard ?