I'm having a problem in an area where I do not have much experience. Let me first give some background. We are trying to bring a GM1 back to working condition after a 2 year hiatus. A month ago we found that a copious amount of water had gotten into the fuel tank. We tried extracting most of it and put some fresh fuel in the tank, cleaned the primary filter and replaced the secondary one, bled the air out of the lines and the engine started and ran good. We ran it for around 15 minutes and shut it down as we knew we really had to empty the fuel tank and get it cleaned. Well we finally got around to cleaning the tank and putting in some fresh fuel, once again drained the water separator and replaced the secondary filter, bled the air out of the lines and it wont start and wont even fire at all. Tried to see if we were getting fuel to the injector and nothing. Removed the fuel line from the injection pump to the injector and made sure it was free of any obstruction yet no fuel is coming out the fuel injection pump. My question will the fault be due to the fuel injection pump or could a fault in the governor system cause the fuel injection pump to malfunction. Getting ready to remove the pump but would like to hear any fixes or recommendations. Thanks.
Engine wont start.
- Thread starter Benny17441
- Start date
you could have air still in the lines or even a blockage in the fuel pick up tube in the tank check all lines coming from the tank for flow all the way to the injector pump...if no one has messed with the timing since you last run it there should not be a timing problem oh and make sure you fuel shut of is in the run position
Cannot ascertain if the injector is spraying as cannot get fuel up to it. Fuel is flowing fine from the tank to the injector pump and the lines were properly bled (a few times). When I removed the fuel line that goes from the injector pump to the injector I can see fuel seeping out of it but even if I crank the engine with the line off it will not shoot fuel out. The pump definitely not pumping. If anyone has had a similar problem in the past I would appreciate some comments and recommendations that might be of help.
Make sure your fuel pump is working and that your filters are tight and not sucking air. It does not make sense that your injection pump would just go bad after it had been successfuly working. Typically when something stops working, recheck the stuff you messed with after it was working and before it stopped working. Fuels pumps do typically go bad before and injection pump. I believe what you are refering to as an injection pump is really the fuel injection timing ditributer. It still needs the fuel pump to be working to supply fuel to it. If you are just getting a dribble out of the line to the injector I would bet your not getting fuel to it, hence something to do with the fuel pump. Got the T-shirt you are earning right now. Hope this helps.
Scott
Scott
you must make certain the fuel is getting TO the injection pump....
you mentioned you replaced the secondary filter a second time... how about the primary?
primary filters usually need changing more often than secondary does...that is if you are using good primary filters.
the secondary is only an insurance filter to save the pump in the event of a primary filter failure. the primary should do almost all of the work.
if you had any water in the lines or maybe a bit of residual in the tank, it could have clogged the primary....
almost always there is a balance point in the life of a fuel filter where the engine will continue to run with a dirty filter because the lift pump is pumping faster with a bit more pressure than it would be when its cranking.
so, when the engine gets shut down and then sets for awhile it will not be able to create the pressure or the volume to supply the injection pump for start up....
on the inlet sideand the injection pump will NOT help suck the fuel. an injection pump in good condition needs at the very least 8psi to allow it to create the pressure the nozzles need to pop and spray the fuel...a worn pump may need a few more psi to operate well enough to get it going.
a good lift pump will deliver between 18 and 22lbs of pressure, and if it doesnt deliver this pressure its because it has some wear in it, although it may continue to deliver satifactory service for a few more years, but if the output pressure is down below 15psi, its time to replace it.
as for the injection pump going bad, it would be a rare thing for it to go bad all at once....especially where you had it running fine just a bit earlier..
usually injection pumps fail as they set, over time, with contaminated fuel in them.... internal rust/corrosion.... then the internal parts cant move, or they do move and then stick....
UNLESS there was a bad filter that let some contaminants thru, but as unlikely as this is i think you will find the problem elsewhere.
make sure the fuel didnt all run back to the tank in the supply line.... ive seen where this has happened and air had gotton into the line... then when the filters were being primed, everything seemed to prime perfectly.
but the engine wouldnt run.... because there was still air in the supply line which caused the injector pump to push air in to the lines going to the nozzles... when this happens the air acts like a spring in there and wont let fuel get to the nozzles. the only way to remedy this is to loosen the lines on the nozzles/injectors and turn the engine over a few times until the air is pushed out and clear fuel is spraying.... then the engine will run.
AND... make sure the fuel shutoff/stop lever isnt sticking in the "kill" position....
Just to add my 2 pennies, I kind of went through what you are now. Engine started and ran ok. I then drained the tank and replaced filters, bleed the lines etc. and the darn thing wouldn't start. I bleed the lines a few more times and it finally started and died. I checked everything I messed with and found I didn't tighten the fuel filter bowl ring tight enough and was sucking air. After a few more line bleedings it started and runs great. A can of Sea Foam in the tank really smoothed things out too.
It is the fuel injector (high pressure) pump. I just took it out and the roller plunger offers very little resistance and there is no pumping action. I agree that it does not make sense that in a month time it goes from a working pump to trash when the engine was not even in use. Contacted our Yanmar dealer and they will have one for pickup on Tuesday for us, the service manager indicated it is hardly ever worth it to put any money into them once they fail and recommended replacement. Part #728170-51101 $325.93 (ouch) I'm thinking along the lines that when we shut off the engine a month ago the cam stopped at a position where the plunger was compressed and it just got gunked in place by questionable fuel. I'm going to attempt to disassemble it and I will dunk it in penetrating oil to see if it loosens up. I saved the shims to be able to adjust the timing.
As a final posting for those interested I was able to free the pump's plunger which seemed to have gummed up by dipping it overnight in a carburetor cleaner solution and a little prying with a small screwdriver. Now that it was free the plunger was to hard to depress with just my thumbs so set it down on a carpet and pushed down on the body and was able to depress it with and it was returning by itself as it should have. Long story short, put it back in the engine lining it up with the governor fork lever, put the fuel lines back and bled the system once more and the darn thing started right away and ran for an hour without skipping a beat. It was turned off and left to rest for 30 minutes and it started right back up again. I called Our yanmar dealer and cancelled the order for a new pump which was done with no problems. I just hope the cylinder was not scored giving it a chance in the short run to get stuck again. I also hope we get no air leaks as a result of messing with the fuel lines. Hopefully with new fuel it will not get fouled again and continues to operate properly. Someone is $325 happy and I see a nice dinner coming. This has given me some experience in an area that I had none and it was quite easy to re-install the pump. For those that asked why I did not replace the primary filter this is an old setup where the primary mostly acts as a water separator and has a hard element that can be cleaned. The secondary was replaced a 2nd time to eliminate the possibility it had been permeated with water. Thanks to all.
Seafoam works wonders on diesel engines also as a gum and varnish remover... im thinking its time for your system to see some of it....
Seafoam, saw it at WM the other day, I'm definitely going to try to help prevent gumming. Centerline, thanks for the heads up.