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D311 Genset fuel problem
D311 Genset fuel problem
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Posts: 208
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17 years 2 months ago #9428
by tomseabee
I got the pony working well on the genset with a little carb work and spun the main engine over. No joy on fuel pressure. I checked the obvious things like fuel in the tank and then drained the filter body and changed the filters (hadn't done that and didn't know their condition). Pressured up the fuel tank with the bleeders open on the filter body and injectors. Could hear a slight bit of air coming through the bleeder ports but after a long while never got any fuel. I then pulled the cover (filter body empty), filled the body with diesel and spun everything again with the pony, still no pressure.
The transfer pump on this engine is a bit different in not having a bypass valve and spring so that's not the problem. I pulled the transfer cover off and it looks good with little or no wear on the gears or end plate.
I ran out of light before being able to check for blockage. I get fuel to the transfer pump through the fuel line but with the fuel line connected and the pump cover off, I don't get good fuel flow. I'm guessing there is some trash in the inlet side of the transfer pump plugging flow. I can't imagine what would be picked up in the tank and perfectly sized to nearly fully restrict that inlet port, but it's the next step. I'm going to pull the transfer pump this afternoon and have a look in better light (also in a shop with compressed air).
Any suggestions??
Thanks,
tom
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17 years 2 months ago #9429
by ccjersey
Whatever it is, it's very good you caught it before it went through the pump. Probably a blob of diesel sludge and rust.
Our 212 grader went from great fuel pressure to zip over time. Most likely from eating debris out of the tank and recirculating it back through the bypass. I had drained the tank, flushed out the line etc, but there must have been enough left in there to do it. When I opened the relief valve/inlet fitting, there was a lot of rust in the bottom of the spring recess.
Your engine (with a bypass up top on the housing??) will at least not recirculate dirty fuel through the transfer pump.
D2-5J's, D6-9U's, D318 and D333 power units, 12E-99E grader, 922B & 944A wheel loaders, D330C generator set, DW20 water tanker and a bunch of Jersey cows to take care of in my spare time:D
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17 years 2 months ago #9430
by SJ
Yes normally if the fuel tank is lower than the pump that they have a return line from the side of the filter housing & that little block that it screws into will have the relief valve inside it instead of in the transfer pump. Check it & maybe it,s stuck open with junk or some other reason. Also you could try sticking the suction line in a container of fuel & not draw from the tank & see if it makes a difference, just a couple things to check. I,ll never forget one time they brought an OTR truck in that would cut out soon after it was started & what I found was the glass lens off a flash light in the left fuel tank & when it was started & run a little bit would suck that glass over the pickup line & cut the supply off & the truck would stall out.I fished it out of the tank & got him on his way.I guess someone was looking in the tank for sme reason sometime & the lens dropped off & I guess they thought it wouldn,t hurt anything but they were wrong.
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17 years 2 months ago #9432
by tomseabee
CCJ, it remains to be seen if it's blockage. I just can't think of anything else and until that is elliminated, it's the next step. Man, I thought when I got the pony purring along, this was gonna be a cake walk. Murphy is still alive and well.
The bypass comes off the top of the filter body and dumps back in the tank right next to the supply line.
Yeah, I caught it all right. I tried my damnest to get that slug into into the pump gears. It's just dumb luck that I only had a bicycle pump to pressure up the fuel tank and could only get a pound or two in the tank. If I had my compressor handy, I could have put 80-90 pounds on it
and really screwed it up. I never cease to be amazed at how lucky (ah - what I meant to say how smart I find myself sometimes).
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17 years 2 months ago #9433
by SJ
Normally the transfer pump works in the range of from 15 psi to max of in the lower to middle 20 psi.on the engine you have. I dyno tested 100s of engines & always used a fuel gauge with the lbs. on it & that,s where they ran.I used the same type gauge with the numbers on it for oil pressure & also if turbo charged to check manifold boost pressure. The only thing with boost pressure it,s given in inches of mercury (HG) so that,s twice PSI so you,d take half the HG specs.
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17 years 2 months ago #9443
by tomseabee
I pulled the pump and was greatly underwhelmed by the amount of debris in the inlet port. It was not a glob of anything but more a loose assortment of what looked like rust flakes. I guess if they all stood sholder to sholder in the narrow part, they could block some. It's hard to imagine how that happens without something larger starting the process. My guess on the source of rust is the fuel level guage which was kinda pitted on the lower end.
Some Rust Blaster was sprayed in the inlet port and purged with compressed air. Several iterations of that has apparently cleaned the pump out. Of course the starting cap on the compressor took that opportunity to short out but I had enough air reserve to complete the job. It's been my experience that happen in 3s. First the stopped up transfer pump, second the compressor starting cap, third
???
I did the normal things like drain the fuel tank after transportation stirred things up but suppose the debris was already in place. I will pressure up the tank and flow a few gallons of fuel through the supply line to be on the safe side. I may also install a in line fine mesh screen between the tank and the pump.
Thanks,
tom
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17 years 2 months ago #9525
by Jack
Tom, I'm real glad to see you've found a D311 set. Hope you get through huricane season without needing it too much!
I've found nothing cleans out a fuel tank quite as well as removing it, turning it upside down and steam cleaning it inside. Pressure wash doesn't seem to do the job quite as well as the hot, wet steam, upside down so it can drain through the biggest hole in the tank--the filler. If you got crud, this is well worth the extra work.
I got the impression that reliability is everything here.
Jack
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17 years 2 months ago #9532
by tomseabee
Hi Jack,
Great to hear from you again. The little D311 has been a education for me. It weighs a bunch more than I anticipated, is nearly 9' long, slobbers like nothing I've ever seen
but it does put out power. I didn't leave it running for long when I saw how much oil it was dumping out the exhaust.
We dodged a bullet with the little "pop up" cat 1 hurricane a week ago and nothing on the radar screen for the short term.
I may have time to get a miss and the slobber issue corrected before I need it. The miss might be that I haven't fully bled the air out.
Are you planning to attend the Richmond show this week?
tom
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17 years 2 months ago #9533
by SJ
99% of the time the slobber is caused by too much idle or no load on an engine so if you can but I know it,s hard with a gen. set like that but put it to hard work if you can find a way to use the power to do it & keep it on for a good couple hours or half a day if possible & see what happens.Also another thing make sure the engine is running up to operating temperature which is very important all the way around esp. with this slobbering problem.
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17 years 2 months ago #9536
by tomseabee
SJ,
Thanks for the advise! I know a good long term load is the trick on the tractors, but you are right on the money with the difficulty loading a genset. I don't have a 3 phase load available and haven't made the conversion to single phase but do plan to put some load on it and run it awhile at operating temp. Before I do that, I'll have to move it out of the building its in or make a exhaust oil collector or hire someone to standby with a hazmat suit and a shovel to take care of the oil residue.
All kidding aside, I plan to build a baffled box with a drain to reduce the mess.
tom
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D311 Genset fuel problem
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