SERVICE BULLETIN - McKenzie Tank Lines

1 SB-222-011 Page 1 of 2 SERVICE PUBLICATIONS, ALLENTOWN, PA 18105 MACK TRUCKS, INC. 2005 SERVICEBULLETINNUMBER: SB-222-011 DATE:2/23/05 MODEL: E-Tech , ASET (Also applies to Mack Trucks Australia) fuel System Priming Procedures E-Tech and ASET EnginesPriming the engine fuel system may be required for various reasons, most commonly, whenair is introduced into the system during fuel filter changes or when components such as thehigh-pressure injection Lines are removed and replaced. Depending upon the amount of fuelthat may have drained from the system, the engine may be very difficult to start and will runvery rough for a short period of time, or in more extreme cases, will not start at of fuel leakage from the high-pressure fuel line connections at the cylinder headhave been noticed, usually after the fuel Lines have been reinstalled or replaced.

2 Typically,after fuel line replacement, the method used for bleeding the fuel system has been to loosenthe high-pressure fuel line connections at the cylinder head (one at a time), and then usingthe hand primer pump to bleed air from the system. This practice, however, can cause fuelto flood the fuel line and injector sleeve cavity in the cylinder head. After the primingprocedure has been completed and the line nuts tightened, fuel inside the cavity will weepfrom the line connection for some time, giving the appearance of an ongoing fuel leak. Thisindication of a fuel leak has resulted in many fuel Lines being replaced unnecessarily.

3 Toavoid this, DO NOT loosen the high-pressure fuel line connection at the cylinder head whenpriming the fuel system. Instead, use the procedures outlined System PrimingThe only acceptable method for priming the fuel system is to usethe hand primer pump located on the right-hand side of theengine. DO NOT attempt to prime the fuel system by applying airpressure to the fuel tank or by using an auxiliary pump, as thesemethods may result in severe engine damage caused by fuelthat has leaked past the supply pump seal and into thecrankcase.

4 If the fuel filter is being replaced, prime the filter by pouring cleanfiltered fuel through the series of small holes at the top of thefilter. DO NOT prime the filter through the center hole. Use careto prevent dirt from entering the center hole of the filter. SB-222-011 Page 2 of 2 For fuel supply pumps having the pump-mounted secondary fuelfilter and the pre-pump filter screen, remove, clean and reinstallthe filter bowl and screen prior to bleeding the fuel If the unit pump outer heat shields have not been removed for a repair procedure suchas high-pressure fuel line replacement, unit pump replacement, etc.

5 , remove them atthis Loosen the high-pressure fuel line nut (only slightly) at unit pump No. Operate the hand primer pump and observe that air and a small amount of fuel ispurged from the fuel line-to-unit pump When the air has been bled, tighten the fuel line nut to 30 lb-ft (41 N m).5. Repeat steps 2, 3 and 4 for the remaining fuel Lines , one line nut at a time, until all sixlines have been Clean any spilled fuel from the unit pump and the Start the engine. The engine should start easily, but may run rough for a short period oftime until any remaining air is completely bled from the the engine does not start after a reasonable period of time (1or 2 thirty-second cranking periods)

6 , or it starts but immediatelystalls, repeat steps 2 through not crank the engine continuously for more than 30 secondswithout allowing the starter motor to cool for approximately twominutes between cranking Run the engine until reaching normal operating temperature, and then check the fuelsystem for Perform a short road test, and again, check for Shut the engine off and reinstall the unit pump outer heat shields.