Isuzu Trooper - Isuzu Trooper
1. Maintenance instruction
2. Maintenance
3. Engines
   3.1. Specifications of the engine and adjusting works
   3.2. Electric equipment and capital repairs of engines
   3.3. Diesel engine 2,8 liters
      3.3.1. Introduction
      3.3.2. Technical characteristics
      3.3.3. Check of a compression
      3.3.4. Top dead point of the piston No. 1 (BMT)
      3.3.5. Gaps of valves
      3.3.6. Cover of a head of cylinders
      3.3.7. Pulley of a bent shaft
      3.3.8. Casings of a gear belt of the drive of the camshaft
      3.3.9. Gear belt of the drive of the camshaft
      3.3.10. Asterisks of a gear belt, natyazhitel and intermediate pulleys
      3.3.11. Yokes and pushers
      3.3.12. Head of the block of cylinders
      3.3.13. Oil case
      3.3.14. Oil pump
      3.3.15. Oil heater
      3.3.16. Epiploons of the camshaft and bent shaft
      3.3.17. Flywheel
      3.3.18. Fastenings of the engine / transmission
4. System of decrease in toxicity
5. Fuel system
6. Transmission and running gear
7. Suspension bracket and steering
8. Brake system
9. Body
10. Body electric equipment
11. Diagnostics of malfunctions
12. Electrical circuitries





Isuzu Trooper>> Engines>> Diesel engine 2,8 liters>> Check of a compression

3.3.3. Check of a compression

GENERAL INFORMATION

Check of a compression


Prevention

For conducting this check it is necessary to use the special tester of a compression intended for diesel engines.


If the engine does not work or there is an admission of ignition (the fuel system is serviceable), check of a compression can establish the reasons which resulted in malfunction of the engine. If you carry out this inspection regularly, then will be able to prevent in advance any malfunction before more serious signs appear.

For conducting check of a compression it is necessary to use the tester intended for diesel engines as pressure in the diesel engine much more exceeds pressure in the ordinary engine. The tester is connected to the adapter which is twisted in an opening of a candle of prestarting heating or in an injector opening.

Besides instructions which are attached to a tester take the following into account:

  – the accumulator has to be charged, the air filter has to be pure and the engine has to be warmed up to the normal working temperature;
  – all candles of prestarting heating have to be unscrewed before carrying out an inspection;
  – unscrew a fixing nut and disconnect a socket fork from the locking valve of the injecting pump to prevent fuel injection.

PERFORMANCE ORDER
1. Owing to special properties of system of bystry warming up of the engine it is necessary to disconnect the throttle valve of system from a collector to carry out an exact inspection of a compression.
2. For this purpose weaken fixing clips and pick up the phone connecting the throttle valve to an intermediate metal cooler.
3. Disconnect vacuum hoses from the throttle valve, having taken the correct arrangement of hoses into account.
4. Weaken the clip fixing a tube of the throttle valve to a collector.
5. Unscrew fixing bolts and disconnect the throttle valve from an inlet collector.
6. Twist an adapter in the first cylinder and connect pressure sensor to an adapter.
7. Turn a bent shaft of the engine by means of a starter; after one or two turns pressure of a compression has to increase to a maximum, and then be stabilized.
8. Write down the highest value which was reached by pressure.
9. Repeat check on the remained three cylinders, writing down value of the highest pressure for everyone.
10. In all cylinders pressure has to be approximately identical;
the difference more than in 2 bars between any two cylinders means malfunction.
11. Consider that in the serviceable engine the compression has to accrue quickly; the weak compression at the first step of the piston after which slow gradual increase of pressure follows during the subsequent steps, means that piston rings are worn-out.
12. The weak compression at the first step which does not accrue during the subsequent steps, means that there is a leak via valves, or laying of a head of cylinders is broken through (also the crack in the head can be the cause).
13. The deposit on the lower parts of heads of valves can become the reason of a low compression too.

Prevention

It is more difficult to define the reason of a low compression in diesel engines, than in petrol. The method of damp check when in cylinders a small amount of oil is filled in, in this case is unacceptable as there is a risk that oil will settle in a vikhrekamer or in deepenings of a head of the piston instead of proceeding to piston rings.


14. Though in exact sizes of pressure of a compression are not specified, you can take for the management that fact that if pressure in any of cylinders is less than 20 bars, then it is the sufficient reason to consider the cylinder faulty.
15. Upon termination of check connect a fork of a plait of wires in a nest of the locking valve of the injecting pump and screw in candles of prestarting heating.
16. Install the throttle valve of system of bystry heating of the engine into place, having checked that all hoses and tubes are connected correctly.

Check on existence of leaks

Check on existence of leaks is necessary to measure pressure with which there is a leak of compressed air from the cylinder.

This check is an alternative to check of a compression and is much more effective than it as the air which is coming out under pressure allows to define easily the place of leak (piston rings, the valve or laying of a head of cylinders).

The equipment for conducting check on existence of leaks is usually inaccessible to the simple motorist therefore, if necessary, you carry out this inspection in specially equipped workshops.