the isuzu C series of diesel engines is one of the most reliable classes of diesel engines
to date, even from the 1970's this 2 litre OHV diesel engine has proven itself
for eons of work here in the Philippines. now I have posted a process on how to
test an Isuzu C engine's pneumatic governor system for air leaks for our visitors who
have problems with this class of engine which includes the following:
1. engine is dying when the accelerator is relieved
2. Abnormal Idling
3. unsustainable idling
the C190, C221 and early variants of the C240 uses a Diesel kiki(Zexel) inline
injection pump and the pneumatic governor system is designated as "RBD" to regualte
the injection pump's fuel delivery. there are 2 hoses, "suction" which is connected
to the most end part of the governor, and the "discharge" which located just behind
the last connector of the injection pump.
what to do:
first disconnect the suction hose as illustrated above, and leave
the discharge hose.
next push the idling control lever (you will see a lever below)
then press your thumb into the suction opening, and let go
of the idling control lever and observe if the idling control
lever moves backward. if it moves instantly, you have a broken control
diaphragm, if it moves slowly or not rapidly, you may need to re-tighten
the 4 bolts that hold the diaphragm chamber or you may have to check
your diaphragm again for possible micro-punctures.
if there is a problem with your diaphragm its advisable to buy a new one
instead of installing the old one back or find a surplus replacement.
remember, pneumatic governor diaphragms
tend to lose elasticity when they age or experience rough usage,
better yet buy a new one!