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View Full Version : how do you purge a diesel engine?



raaaid
09-10-2007, 07:01 AM
a posible exam question

Jediteo
09-10-2007, 07:14 AM
Call Stalin or the Spanish Inquisition, they know all about purging

K_Freddie
09-10-2007, 07:18 AM
It's usually called 'bleeding'. Purge is an older name for it AFAIK.

On top of the fuel injector or piston inlets there should be air-bleeding valves. You open these to get rid of any air in the fuel system.

http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

rhinomonkey
09-10-2007, 07:22 AM
diesel engines will have some kind of manual pump to pump fuel round the system to bleed out air from valves situated somewhere on the fuel system . Also IIRC you need to bleed off water (usually collects in a fuel line filter)

Monterey13
09-10-2007, 07:29 AM
You should open the system between the pump and the filter. Operate the hand priming pump until all air is removed and only clear fuel flows from the line. Then close the line. Repeat the same procedure at other points in the system, such as between strainers and the filters, between the filters and the high-pressure pumps, and at the overflow line connection (excess fuel return line) on the high-pressure pump housing. In small, high-speed diesel engines, you may need to prime only at the overflow connection. Since priming high-pressure lines is time-consuming, attempt to start the engine before purging these lines. However, do not crank the engine for more than the specified interval of time. If the engine still fails to start, you should prime the high-pressure lines.

T_O_A_D
09-10-2007, 08:18 AM
Monterey13 covered it pretty well.

Not all Deisels are the same, the ones with external Injectors, are the easiest to bleed out the air, Just cracking the Injector lines at the Injector's/Nossles and hand pumping if set up with one will get it going.

If no hand pump, then if you have acces to an aircompressor you can with a blow gun,and a rag pressurize the fule tank to force fuel up to the injectors.

If it is an Internal Injection Engine, same rules, short cracking lines at Injector itself.

On those its just easier to crack the return fuel line, and presurize the system till you get fule flowing.


At the last resort you can remove airfilter, or a plug to get acces to the intake of the engine.

If you have a friend who can crank the engine, once cranking you can spray WD40 or something equivelant with an oilbase directly into the intake, and get the engine to run long enough to draw its own fuel up, and run on its own. BY ALL MEANS DON"T SPRAY EITHER INTO IT!!!!!!!!!!!!!!!!!!!! Thats a very fine art, and if done incorrectly , it can cause damage to the engine.

HotelBushranger
09-10-2007, 08:23 AM
how do you purge a diesel engine?

Stick your fingers down its throat.

Daiichidoku
09-10-2007, 08:42 AM
hit it with a bigger hammer

ytareh
09-10-2007, 01:47 PM
This has to be done when changing a diesel fuel filter .In my limited experience and having made a mess of it a couple of times it pays to fill the diesel filter up with diesel as much as possible before reinstalling to avoid non starting cars !!!

Jasko76
09-10-2007, 04:39 PM
Please remove the diesel engine and replace it with a nice high-revving petrol engine. Diesel is ****!

mortoma
09-10-2007, 08:07 PM
There was a guy at a gas station I tried to help not long ago, who ran out of diesel fuel just before getting to the pump to refill. He could not get it started and I ( among others ) helped him push his large pickup off to the side until he got it going. Was a purge what he needed?? His truck was sitting there several days after that!!! Seems to me that running diesels out of fuel is a bad idea!!

RamsteinUSA
09-10-2007, 08:21 PM
his igniter probably went out.... so you could not do anything to help him..

Targ
09-10-2007, 08:45 PM
Originally posted by mortoma:
There was a guy at a gas station I tried to help not long ago, who ran out of diesel fuel just before getting to the pump to refill. He could not get it started and I ( among others ) helped him push his large pickup off to the side until he got it going. Was a purge what he needed?? His truck was sitting there several days after that!!! Seems to me that running diesels out of fuel is a bad idea!!

Running any vehicle out of fuel any more is a bad idea as the fuel pump will burn up, same with running the fuel tank low all the time as the fuel helps cool the pump.

JG14_Josf
09-10-2007, 09:00 PM
If no hand pump, then if you have acces to an aircompressor you can with a blow gun,and a rag pressurize the fule tank to force fuel up to the injectors.

We ended up making a fuel cap pressure regulator for Detroit engines on off-road trucks used by careless drivers (or drivers wanting a break) as they sat with an empty fuel tank and dead batteries.

As described by Toad the routine included a small amount of pressure applied to the fuel tank and bleeding the injectors to fuel line connections.

Catapillar engines were easy beause they had hand pumps on the fuel pump.

In a pinch you can try mouth to fuel line resesetation.

P.S. If it won't ignite on ether (http://www.quickstart-ether.com/aboutether.php) then the problem may not be fuel starvation.

Waldo.Pepper
09-10-2007, 10:19 PM
This thread wasn't stupid and full of nonsense.

I only went away for three days what happened? I'm confused.

Charos
09-11-2007, 05:44 AM
Originally posted by K_Freddie:
It's usually called 'bleeding'. Purge is an older name for it AFAIK.

On top of the fuel injector or piston inlets there should be air-bleeding valves. You open these to get rid of any air in the fuel system.

http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif


In a similar fashion if you bleed or "purge" a compressed air engine, you can remove diesel from the fuel system. http://forums.ubi.com/images/smilies/winky.gif

Ritafang
01-25-2018, 10:16 AM
Regular maintenance of a diesel engine can keep the machine run well and prolong the engine service's life. I don't which brand of the engine you use. Cummins diesel engine maintenance (http://www.dieselgeneratortech.com/diesel-engines/Cummins-NT-diesel-engines-maintenance-manual.html). Diesel engine maintenance tips (http://www.dieselgeneratortech.com/diesel-engines/maintenance-tips-for-diesel-engine.html).

Hope it can help you.