How do I replacing the front injector pump seal on a 2004 kia pregio van?

You need an auto electrician with a pro grade scan tool computer. He will check for DTCs and Communication errors between sensors and modules..

https://www.google.com/search?q=2003+Kia+Pregio+Van.+speedometer+and+temperature+gauge+do+not+work

..

I don't know - sorry.

Just wanted to advise you; If it is an injector pump you should before removing it, learn how to replace it. An injection pump has to be precisely timed to the engine and sometimes special tools are needed and reference to a good repair manual.
If this applies to your vehicle set up, you will probably need the services of a diesel specialist or dealer.

If your vehicle is a common rail diesel type it doesn't have an injection pump but does have a high pressure diesel pump that will not need timing to the engine.
If the pump of either type is failing, once removed they should be carefully flushed so any swarf or debris they contain is visible to careful inspection. If swarf is present the injectors should be serviced and the pipework and fuel rail thoroughly flushed.

Before working on a diesel fuel system it is very important the area of repair is clean and free of water and as the work progresses each pipe end and fuel orifice is covered or plugged to prevent the ingress of even the tiniest particle of dirt. Using a compressed air blowgun during reassembly makes doubly certain there is no dirt inclusions...

At the end of the large air inlet hose to the engine inside a plastic air filter box.

is the engine 27diesel J2 ? If so just unbolt all the injectors pipes from top and loose the bolts on the feeding pump side so to enable you to move the pipes.then with a socket of 17mm remove all the bolts (4 pcs) from the injectors holding the return pipe.With a 22mm socket start loosing one by one the injectors and remove them from the cylinder head be careful not anything or any dirt dropped int he injectors holes.

To replace headlight bulb of kia pregio van: You only need Phillips screw driver and 10mm socket or open wrench. Open the hood, remove front grill with 4 phillips screw. This will give you room for your hand to pull out the headlight housing later on. Next is remove the signal light housing by unscrewing the phillips screw on top of the headlight housing then pull out the signal light housing and remove the bulb. You will see 2 pcs 10mm bolts on the side which hold the headlight. Loosened and remove the bolts on headlight holder then pull the headlight sideward. Remove power supply socket before removing it completely from the van. Remove bulb socket, spring clip, and busted bulb and replace with new one. Reassemble the disassembled parts in reverse order. That's it, will take you only 10 minutes.

how can i change spark plugs in kia pregio

is this a common rail diesel engine ??

this has to done at the dealership

it is most likely the pump because with a clogged injector it would still get gas in the other 5 injectors