PIN AS 1444095 - Caterpillar

Worn Injectors:
Symptom: Machine is hard to re-start after it reaches normal "hot" engine operating temperature and is shut-down. Usually, the machine will start easily when the engine is cool, such as the first start of the day. Difficulty re-starting when "hot" (if due to worn injectors) may be due to the loss of injector plunger/barrel pumping efficiency because hot fuel is thinner than cold fuel and plunger/barrel leakage is too high at cranking Rpm (200 to 250 Rpm).
TEST
a) Run the engine until it reaches normal operating temperature and shut it down.b) Remove the engine valve cover and install the Indicator Fixture Gp. and Indicator as if you were going to check the engine fuel setting (rack setting). See topic "Fuel Setting" in the Systems Operation Test and Adjusting Section of the Engine Service Manual for details on tooling. When installing the fixture group and indicator it will not be necessary to remove the fuel shut-off solenoid.
c) Zero the Indicator with the fuel shut-off in the Fuel Shut-off Position. The CH35,45, and 55 utilize an energize to run (ETR) Fuel shut-off solenoid which energizes when the key switch is turned to the on position.
d) After zeroing the indicator turn the key switch to the on position and observe movement of the indicator. The indicator should move from the 0.0mm position to a positive position (.5 to 2.0mm). If no movement is observed, see topic "Control Shaft Sticking".e) Continue to observe the indicator and turn the key to the "start" (crank) position. As the engine turns over the rack should start moving to a higher positive position. As the rack increases observe the point at which the engine fires (starts). It should start when the rack reaches 2.0 to 4.0mm. If the rack increases to more than 4.0mm and the engine fails to start, the injectors are worn and require replacement (See Topic "Injector Replacement" for additional instructions). If the rack fails to move or hesitates to increase as the engine is cranked, see the topic "Control Shaft Sticking". Control Shaft Sticking:
If "hard starting" can be corrected by exercising the throttle (governor control), move the throttle to the full fuel on position, back to idle and then to or throttle position, then the cause is not worn injectors. If exercising the throttle allows an engine to start, it means that at the "low idle" position, the governor does not have enough force to open the rack control shaft. Usually, the cause is an improperly adjusted Fuel Control Shaft Assembly. Exercising the throttle as noted, prior to or during cranking, changes the control linkage position and causes the governor to exert more force on the control shaft mechanism thus forcing the injector racks to move and allows the engine to start. This is usually traced to improper control rack as. installation and adjustment. Specifically, adjustment of the two center-supports for the control shaft must be done properly or the shaft may not rotate freely, and may "stick" in the