In-Chassis Part/Component Procedures; Electronic Unit Pump (Eup) Replacement - Mack E-TECH SB-210-034 Service Manual

5_106_00.bk Page 286 Friday, August 4, 2000 11:17 AM
IN-CHASSIS PART/
COMPONENT PROCEDURES
This section presents four standalone
replacement operations which can be done in-
chassis and not involve a full engine overhaul.
These operations include Electronic Unit Pump
Replacement, Camshaft Replacement, Engine
Brake Control Valve Replacement and Valve
Lifter H-Ring Installation Check.
Electronic Unit Pump (EUP)
Replacement
[221 GP]
To properly service the electronic unit pumps
(EUPs), it is essential to understand unit pump
removal, pin and tappet installation, and unit
pump installation. Each of these procedures is
covered individually.
UNIT PUMP REMOVAL
When it is necessary to remove more than one
EUP, the removed EUPs must be paint-marked
with the cylinder number, and reinstalled at their
original locations. This will eliminate any need to
reprogram EUP information. If a new or
remanufactured EUP is installed, reprogramming
must be performed as described at the
conclusion of the EUP installation section.
1. Remove the heat shields.
2. Clean the EUP and cylinder block around
the EUP to ensure that no debris enters the
engine during EUP removal.
To avoid engine damage due to debris entering
EUP bores of the cylinder block, step 2 MUST be
followed.
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REPAIR INSTRUCTIONS
3. On chassis with inlet manifold-mounted fuel
4. Place a drain pan beneath the right side of
To ensure that minimal fuel enters crankcase oil
during EUP removal, steps 3 and 4 MUST be
followed. To avoid fuel spillage, do not crank the
engine with the starter at any time during EUP
removal or replacement.
5. Remove the injection tube.
6. Remove wire terminals from the EUP.
7. Remove the inboard EUP screw completely.
8. Loosen outboard EUP screw and back it out
9. Insert screwdrivers under the bolt bosses
The EUP spring may be preloaded with
significant spring tension, depending upon
cam lobe position. To avoid injury from the
EUP springing outward, steps 7–9 must be
followed.
10. Remove outboard EUP screw completely
filters, remove both the inlet and outlet fuel
hoses from the secondary fuel filter. This
allows additional fuel to drain from the hose,
through the cylinder block, and out of the
internal passages.
On chassis with remote-mounted fuel filters,
remove the fuel hose from the cylinder block
fuel-inlet fitting, which is behind the EECU at
the top. This allows additional fuel to drain
through the cylinder block and out of the
internal passages.
the engine. Remove the fuel-outlet fitting
from the cylinder block fuel return gallery
above the air compressor. This allows fuel to
drain from the internal passages.
1/2 inch.
(front and rear) and pry until the EUP comes
out against the screw head. (The EUP may
spring out against the screw head.)
and remove EUP from the cylinder block.
Place the EUP in a clean area and cover it to
prevent entry of dirt and other contaminants.