Figure 2-288. Wrong gear

TM 9-2320-211-20

and transmission components results. The rpm

chart also reveals constant alternation between high

and low rpm. The engine can easily be run at ex-

cessively high rpm (fig. 2-288).

Figure 2-290. Engine idling.

(9) C o l d s t a r t i n g a n d w a r m i n g u p t h e

engine. In figure 2-291, the chart shows that the

engine was accelerated to maximum rpm when

cold; this can dause damage to the pistons and

other parts of the engine. Recording of idling for

(7) Engine run at excessively high rpms. T h e

several minutes during duty hours points to the fact

that the engine has been warmed up (fig. 2-292).

speed chart does not reveal this fault in driving. On

the other hand it can be seen clearly from the rpm

Speed recording does not begin until after this.

chart that the permissible maximum rpm is con-

stantly being exceeded (fig. 2-289).

Figure 2-291. Cold starting.

(8) E n g i n e i d l i n g . In the case of older

vehicles engine idling can be recognized only as a

narrow, jagged band on the time stylus recording

(fig. 2-290). On the other hand, the rpm chart

clearly reveals unnecessary running of the engine

for a period of several hours.