820484A 1 Force RING SET-2 RINGS (9.9) (85A/87A)

Pull-Down RPM Check
The engine must give rated horsepower for this test to have accuracy.1. Actuate the brakes, put the transmission in NEUTRAL and operate the engine at high idle rpm (accelerator pedal all the way down).2. Make a record of the engine rpm.3. Put the BrakeSaver control to the full ON position.4. Make a record of the engine rpm with the BrakeSaver full on.5. The engine rpm with the BrakeSaver full on must be 175 25 rpm less than the engine rpm with the BrakeSaver off. If the difference in rpm is less than 150 rpm, the BrakeSaver is not giving full braking force. If the difference in rpm is more than 200 rpm, check the air pressure to the BrakeSaver control valve. The air pressure must not be more than 42 psi (290 kPa).
Do not run the engine at high idle rpm with the BrakeSaver ON for more than 15 seconds at a time. Let the engine run at low idle with the BrakeSaver off for five minutes to keep from getting the engine cooling system too hot.
Klunk Check (check for free movement of the valve spool)
1. Run the engine until the truck air system is at its maximum pressure and then stop the engine.2. Put the BrakeSaver in the full ON position before the air pressure in the truck air system gets below 70 psi (480 kPa).3. Put the BrakeSaver in the OFF position. A noise ("klunk") must be heard at the BrakeSaver control valve as the valve spool hits the cover at the air inlet end of the control valve.4. If the noise is not heard at the BrakeSaver control valve, remove and disassemble the control valve. Inspect the valve for: a. A damaged valve body.b. Damaged or worn springs in the valve spool.c. Damaged or worn valve spool.d. Damaged or worn O-ring seals or diaphragm in the control valve.e. Closed holes (small holes to feel pressure) in the side of the valve spool.For specific problems, make reference to the PROBLEM INDEX below.
1. Air pressure to control valve. 2. Oil pressure to engine. 3. Oil pressure from oil cooler. 4. Oil pressure to BrakeSaver. 5. Oil pressure from BrakeSaver. 6. Oil pressure from engine. 7. Oil pressure to oil cooler. Fuel System
Difficulty within the fuel system can be classed in one of two groups: lack of fuel or too much fuel for proper combustion.Many times, the fuel system is blamed when the fault lies elsewhere, especially when smoky exhaust is the problem. Smoky exhaust can be the result of a faulty fuel injection valve, but it can also be caused by lack of air for complete combustion, overloading at high altitude, excessive oil burning or lack of compression.Visual Inspection
1. Observe the fuel pressure gauge reading. Lack of pressure indicates difficulty in the supply side of the system.2. Check the fuel level in the supply tank and the fuel tank cap vent for being plugged.3. See that the vent valve is closed.4. Check for leakage in the fuel supply lines and components or for a kinked or restricted supply line.5. Replace the fuel filter element and clean the primary fuel filter.6. Inspect the fuel bypass valve to see that it moves freely and that dirt is not holding the plunger off its seat. Be certain the spring has proper tension.7. Bleed the fuel system to remove trapped air.Testing Fuel Injection Equipment
A simple check can be made to determine which cylinder is misfiring or causes puffing black smoke. With the engine running at a speed which makes the defect most pronounced, momentarily loosen the fuel line nut on an injection pump sufficiently to "cut out" the cylinder. Check each cylinder in the same manner. If one is found where loosening makes no difference in the irregular operation or causes puffing black smoke to cease, the pump and valve for only that cylinder need be tested. Incomplete combustion in this particular cylinder can also be caused by low or no compression (worn or broken rings, leaking or incorrectly adjusted valves) so further testing may be necessary.Checking Fuel Injection Valve
Examine fuel injection valves for:1. Excessive carbon on tip of nozzle or in orifice.2. Erosion of the orifice.3. Screen plugged with dirt.The condition of a capsule-type nozzle assembly can be tested on the Caterpillar Diesel Fuel Injection Test Apparatus, and the rate of leakage of the nozzle assembly can be determined.Checking Fuel Injection Pump Lifter Washer and Pump Plunger
The timing dimension should be checked and adjusted, if necessary, by setting the fuel injection pump timing dimension with the fuel injection pump off the engine. This will assure that the point of the fuel injection is correct. If the timing dimension is too small, injection will begin early, and if too great, injection will be late.When pump plunger wear becomes excessive, the lifter washer may also be worn so it will not make full contact with the end of a new plunger. To avoid rapid wear on the end of the new plunger, replace the lifters having washers showing visible wear.
WEAR BETWEEN LIFTER WASHER AND PLUNGER
Fig. A illustrates the contact surfaces of a new pump plunger and a new lifter washer. In Fig. B the pump plunger and lifter washer have worn considerably. Fig. C shows how the flat end of a new plunger makes poor contact with a worn lifter washer, resulting in rapid wear to both parts.A pump can maintain a satisfactory discharge rate and yet be unserviceable because of delayed timing resulting from wear on the lower end of the plunger. When testing a pump which has been in use for a long time, check the plunger length with a micrometer. Discard the pump if the plunger measures less than the minimum length (worn) dimension. Inspect the upper diameter of the plunger for wear. Performance of pumps worn in this manner can be checked as described in the Instructions for Fuel Injection Test Apparatus.Glow Plug And Precombustion Chamber Removal And Installation
Glow Plugs
Use 6H3425 Glow Plug Tool