DIY 4d56t engine repair

In detail: do-it-yourself 4d56t engine repair from a real master for the site my.housecope.com.

The high pressure fuel pump, in short - high pressure fuel pump is an integral part of modern diesel engines. The high-pressure fuel pump is designed to supply fuel to the cylinders in strictly defined quantities in certain cycles of the diesel engine.

Fuel pumps differ in the type of fuel injection:

  • direct injection of a diesel engine (the supply of a diesel engine and its injection into the cylinders take place simultaneously);
  • battery injection (pressurized fuel is accumulated in a special "accumulator" and then supplied to the injectors).

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Image - DIY 4d56t engine repair

Also, high pressure fuel pumps may differ among themselves in types, pumps can be of the following designs:
  • in-line;
  • multi-section;
  • distribution.

If you do not go into the "jungle" of design differences between pumps of different types, then you can simply identify certain differences between them. In in-line and multi-section pumps, each section supplies diesel to its "own" cylinder. In distribution pumps, one "block" is capable of supplying several cylinders with diesel.

Also, another difference between the injection pump is their "power" - how many cylinders the pump is designed for and its pressure. In general, these are all obvious differences between the pumps. In general, these are the main differences between the pumps.Now we will no longer torment our readers with theories about the operation of injection pumps and their primitive characteristics, which have long been described on the Internet in large quantities. Let's move on to the immediate specifics.

The engine manufacturer Mitsubishi is deliberately omitted here. This is due to the fact that at the moment there are several derivatives of this engine. Accordingly, they have a minimum of design differences, and the injection pump is suitable for both motors.

Video (click to play).

To be more specific, this is the same engine as the Hyundai D4BH, the pump for it has full compatibility with the 4D56T internal combustion engine (the differences between the 4D56 and 4D56T internal combustion engines are insignificant, the "T" index indicates a turbocharged engine).

The pump itself for the above engines, there is only one, produced by Zexel (aka Diezel Kiki), and now BOSCH. Yes, final suppliers and packaging may vary, but in the end, injection pumps for these motors can only be obtained from Zexel or BOSCH.

Basically, the accelerated output of the injection pump on these engines is caused by low quality fuel, as well as by the ingress of foreign elements into the system, which often occurs when loose connections and driving over rough terrain, fords, etc.

The main problems with the injection pump on these engines are as follows:

  1. Damage (due to accelerated wear) of the internal parts of the pump - the plunger pair, bearings and other parts.
  2. Contamination of the filter (protective mesh and element) due to the ingress of foreign elements into the system.
  3. Increased or floating revolutions due to the so-called. "Airing" of the system - the ingress of air into the system due to loose connections and worn out gaskets and seals.
  4. Poor engine start in cold weather, caused by a jammed or broken thermostat (located on the left side of the pump, injection advance mechanism).
  5. Other breakdowns associated with the rest of the elements - spark plugs, automatic heating, fuel supply, diesel injection advance angle settings.

Until now, the debate about which injection pump for 4D56 / 4M40 / D4BH engines is better, electronic or mechanical, does not subside. How big are the differences in the injection pump themselves and the attachment electronics for the pumps. Is it relevant to replace an electronic injection pump with a mechanical one?Let's take a closer look.

So, the main difference in this moment is not the pump itself, but the equipment (electronics or mechanics) that activates the fuel supply system, depending on one or another mode of engine operation. In a mechanical injection pump, activation occurs due to the direct mechanical control of the injection pump. A cable runs from the gas pedal to the pump, which controls the system. In an electronic injection pump (EFI), the gas pedal is already electronic and the system is activated through the accompanying electronic units and sensors.

There is also a version about the existence of a cable drive for controlling an electronic injection pump (there is a control rheostat on the pump itself), but our editorial staff could not verify the reliability of this particular information.

Structural diagram of a mechanical pump:Image - DIY 4d56t engine repair

The advantages of a mechanical injection pump:

  • ease of maintenance;
  • reliability (due to fewer electronic components and sensors, which often "love" fail);
  • cost, as a rule, mechanical pumps are cheaper than their electronic "counterparts".

Disadvantages of a mechanical injection pump:

  • the absence of any indication systems and the quality of the units;
  • the need to fine-tune the parameters and monitor the state of all related elements of the system (spark plugs, fuel pump, diesel injection timing device);
  • increased consumption compared to an electronic pump.
  • slightly worse traction performance at high rpm compared to an electronic pump.

Structural diagram of an electronic pump:Image - DIY 4d56t engine repair

The advantages of an electronic injection pump:

  • more stable operation of the engine, the absence of "floating" revolutions with serviceable accompanying elements (candles, injection advance mechanism, etc.), including electronic components and sensors;
  • reduced fuel consumption compared to a mechanical pump;
  • traction performance at high rpm is slightly better than that of vehicles equipped with mechanical pumps;
  • the ability to read errors through electronic control units.

Disadvantages of electronic injection pump:

  • a large number of sensors and other electronics, and this somewhat complicates car repair and increases the cost of maintenance;
  • difficulties in finding some electronic components;
  • difficulties in the selection of the pump itself and its components, since there are a large number of different variations with hinged electronics and they are different depending on the make and model of the car;
  • the reliability of electronic pump units is lower than that of mechanical ones, since electronic components and sensors can often fail.

Before proceeding with the description of the process of removing the pump from the car, it should be mentioned that this article is not a guide to work on a specific car!

Zexel injection pump (aka Diezel Kiki or BOSCH) is equipped with a large number of cars with 4D56, 4M40, D4BH engines. Moreover, this family of engines is installed on completely different cars in terms of their characteristics and arrangement of units, such as Pajero Sport and Hyundai Oldax, so the attachments will be different in most cases. We will just talk about the pump removal process in general terms, without delving into the design differences between cars of different brands equipped with these engines and pumps.

To remove the pump, you will need to do the following:

  • remove all electrical wiring from the pump itself;
  • remove the cooling pipes from the intercooler;
  • unscrew the high-pressure lines, for this use the key for "14";
  • after which it is necessary to remove the nozzles, this is done with a long head on "22";
  • then remove the washers (2 pcs.) from the wells for the nozzles;
  • after which it is necessary to clean the wells of dirt, etc. and close the nozzle seats with a clean rag or glue it tightly;
  • after the above actions, it is necessary to remove the timing mechanism (for more information about removing the timing mechanism, see the book on repairing a specific car);
  • as soon as the timing is removed, it is necessary to remove the fuel injection pump sprocket and be sure to set marks on the injection pump and the engine block, this is done so that later it would be easier to install the pump and perform its adjustment;
  • as soon as all the above steps are completed, you can unscrew the fastening bolts of the injection pump.

The pump is removed, now, depending on the problems, it can be sent to the service to the master. Well, or do it yourself if the breakdown is not very serious.

The installation of the injection pump is carried out in the reverse order: installation of bolts, connection of vacuum hoses and electricity, etc. However, it should be noted that when installing the pump, be sure to set the marks in the correct position! In addition, it should be remembered that the elements of the high pressure system must be installed using a torque wrench. We attach the tightening forces of each element during installation:

  • nozzles - 55-60Nm;
  • high pressure pipes - 30Nm;
  • return pipes - 25-30 Nm.