All diesel engines will start as long as it is turned over quick enough and the right amount of fuel is added at the right time, even if the compression is a problem, you can use a fuel starter additive to give the engine an extra boost, though it is not recommended other than in an emergency, as engines can become ‘addicted’ to this type of substance and any damage caused will be irreversible.)
SYMPTOMS OF AIR TRAPPED IN THE FUEL SYSTEM
If any air is present in this system, it will not pressurize like fuel; instead, air
squeezes and compacts, which results in the engine cutting out and shut-
ting down. Symptoms such as knocking, racing and surging are common
faults associated with the high-pressure system losing fuel pressure, al-
though the faults can originate from either of the other systems.
BUBBLING AT THE INJECTORS
Fuel bubbling where the injector enters the cylinder head can indicate that the copper washers on which the injectors are seated are leaking. This is usually due to age and indicates that they need replacing, although they may simply need to be tightened, so this is worth a try first.
HOW TO REMOVE INJECTOR PIPES
When removing the injector pipes, it is important to loosen the high-
pressure pipes at the pump end first; this provides sufficient movement for the pipe to be moved clear at the injector end. This avoids bending, which would lead to premature failure and trouble when trying to reconnect the pipework. Some engines have rubber bushes fitted to the injector pipes, which are used to dampen vibration, so they must always be refitted, otherwise, the pipe is likely to fail through vibration.
Diesel Bug and Water Contamination
All diesel contain some element of water. Water content in diesel makes the diesel murky or cloudy and can be the first indication of an issue developing. However, when diesel is left to stand this water separates naturally and as it is heavier than diesel it eventually drops to the bottom of the tank, and hence why the drain tap on the tank offers real maintenance help. Leaving water in your fuel tank will create the ideal conditions for
diesel bug contamination to develop and over time will cause internal rusting of
the tank.
BLEEDING SEQUENCE TRADITIONAL METHOD
The fuel system will require bleeding whenever filters or other components are replaced, or when the fuel tank has been run low. Most modern engines will self bleed: for engines with electric lift pumps simply turn the ignition key to the run position for 20 seconds (first key position); for engines with manual priming lever/plunger operates until consistent firm pressure is felt.
Engines with mechanical lift pumps without manual means of priming will need to be cranked over (turn the key and attempt to start); do not crank for longer than it would normally take to start. Otherwise, follow the manufacturer’s recommendations. This should be undertaken with caution, as it can quickly drain the batteries. To prevent unwanted starting during bleeding (ideally you do not want to start the engine until all the air is bled from the system), either disconnect the electrical connector on the fuel/shutdown solenoid or leave the manual stop control pulled out. Reconnect the solenoid or push the stop control back in when bleeding is complete.
Read more on this barge and narrow boat engine troubleshoot guide in the next article on Barges and Narrow boats….
