1MW Diesel Engine


Thread Starter

sami ibrahim


i have a diesel engine 1MW. When we try to operate it, it fails to start many times before start successfully and no alarms found when start failure happened.

can you give me a recommendations to what i do?

best regards,
sami ibrahim,

We are very distressed to hear about the starting reliability problem with your 1 MW diesel engine.

What have you done to investigate the problem?

What have you done to try to resolve the problem--and, more importantly, what were the results of your efforts?

How old is this 1 MW diesel engine? When was the last time it had any significant maintenance performed on it? What was the most recent maintenance performed on the engine?

Are you certain of the fuel quality (specifically, is it free from water)?

What kind of starting mechanism does the 1 MW diesel engine use (a compressed air starter; an electric motor starter; a hydraulic starter)? Are you certain the starting mechanism is working properly--in other words, does the starting mechanism produce the normal speed (RPM) during starting?

Are the air filters clean? When was the last time they were replaced?

When the engine does start and reach rated speed what does the exhaust look like? Is it white smoke that clears up after a short time, or does the white smoke continue as long as the engine is running, even after being loaded?

Does the exhaust turn black as soon as the engine is loaded?

Most internal combustion engines require three things to start and run:

-Ignition Source

For most diesel engines, the ignition source is the heat of compression of the air by the piston(s). So, if the piston rings or valves are leaking then the air can't be compressed enough to produce enough heat to ignite the diesel fuel which is injected into the cylinders. An excellent indication of low compression and incomplete combustion in a multi-cylinder diesel engine is the presence of white smoke in the exhaust. (If you've every seen a diesel engine lorry driving down the road with white smoke coming out of the exhaust, that's usually the result of bad compression and/or incomplete combustion.) The unburnt diesel from a cylinder or cylinders with low compression and no combustion or incomplete combustion will make its way into the exhaust system and will eventually "burn"--but incompletely, resulting in white smoke. If you see a lot of white vapours exiting the exhaust while trying to start it could be that there is no sufficient compression on multiple cylinders, and if the white smoke continues and does not clear up when the engine does start and run that would also be an indication of low compression in one or more cylinders.

If the air filters are dirty, or there is some issue with the air intake system (some diesel engines have emergency shut-off dampers which can be used to starve the engine of air to shut it off in an emergency--and the dampers are usually latched open and have some kind of spring to close them when actuated) then insufficient air will be ingested by the engine for combustion.

If there is little or no fuel getting to the cylinders, that could be the result of plugged fuel filters, bad fuel (water--which will also damage mechanical fuel injectors and make them unserviceable over time), or a mis-adjusted "fuel rack" (the stroke of mechanical injectors is usually controlled by a mechanical rack mechanism, which can become loose and/or be misadjusted). If the unit has electronic fuel injection, or electric fuel pumps, it could be that one or more of the electronic/electric devices is not working properly. Hopefully, there are gauges or sensors to indicate proper pressures during starting operation, such as before the injectors, and possibly injector pressure.

When was the last time the fuel injectors were serviced or replaced?

Again--it's pretty simple: fuel, air, ignition. Without any one of those three, there won't be combustion, and the unit won't start. (I'm presuming the starting mechanism is working properly and getting the unit to normal starting speed during start attempts.) And, if the injectors don't properly atomize the fuel (which they won't if they are worn or damaged), then the fuel will be difficult to ignite and burn completely (which can also result in white smoke).

If you can tell us more about the engine and its manufacturer and the control system (governor) that would be very helpful. <b>BUT,</b> the most important things you can tell us are:

--What have you done to try to resolve the problems, and what were the results of your efforts?

--Have you checked the air filters? When was the last time they were replaced?

--Have you checked the fuel to be certain it doesn't contain any water?

--Have you changed the fuel filters recently--and if so, did you examine the ones removed to see if they are dirty or show any signs of water or rust?

--What does the exhaust look like during starting and after reaching rated speed? Is the exhaust slightly white, billowy white (large white clouds of smoke), normal brown haze, dark black smoke? Does the exhaust clear up (does the white smoke eventually disappear after reaching rated speed), or does some white smoke remain during operation?

--Do you have a method of measuring the compression of each cylinder, and if so, what are the pressures now, and what are they supposed to be?

Hope this helps! The above list is by no means complete (as we don't know a lot about the particulars of the 1 MW diesel engine at your site), but it should cover most of the basic troubleshooting issues. And, many times, troubleshooting is a process of elimination--you just have to say, "Is [this or that] working properly?" and if it is, then you on to the next possibility, until you arrive at the cause of the problem. (And, sometimes, there can be multiple problems--such as dirty air filters, low compression, and worn or bad injectors!)

Please write back with answers to as many of the questions as you can provide, and to let us know how you fare in resolving the problem!