air in fuel system second try

morgan in ar · Sep 10, 2014

Working on a JD 302-A diesel industrial tractor. Tractor will run fine, then just die suddenly. The tractor will not restart unless I bleed it at the filter. I have drained the tank by pulling the shut off valve, replaced the copper fuel line to the lift pump with a rubber fuel line, and changed the fuel filter (round element type like napa 3166) and O rings. Could it be the lift pump? or could it suck in air past the lift pump? possibly in lines from lift pump to filter? Thanks for the help- Morgan

RayP(MI) · Sep 10, 2014

Had a problem with a diesel PU. developed a pinhole in the fuel line IN the fuel tank between the sock filter and the disk cover in the top of the tank. Would draw air in, filling the fuel filter, prior to the mechanical fuel pump on side of engine. 'Bout drove me crazy running that one down.

Frankmn · Sep 10, 2014

I had one that had a crack in the lift pump where the fitting for the fuel line screwed in. Sometimes it helps to pressurize the fuel tank and look for leaks.

VicS · Sep 10, 2014

Has it set for a while? Started one a while back. The diesel had turned to something that wouldn't run down the fuel lines. Blew the lines with air. The fuel came out like a string. We put some 911 in the tank and stirred it with stick! Needed to drive it home about 6 miles died twice on the way. Blew the line from the tank to the fuel pump out each time. Did it one more time and is alright now. I think it had set for a year.

Bob · Sep 10, 2014

While is certainly may be possible that something is wrong in the fuel supply system, how long has it been since the IP has been rebuilt?

Starting and running and then dying suddenly is how engines with the Standyne rotary IP act when the governor damper ring disintegrates into coffee grounds-like particles and then clogs the IP's output fitting/housing pressure regulating valve.

This is a COMMON occurrence unless the pump has been rebuilt within a reasonable length of time or was previously updated.

If you can do this safely, remove one of the timing access covers held to the IP with 2 flathead screws, and look for coffee grounds-like debris in the fuel.

Start it with the cover loose, and return fuel dribbling out and see if it keeps running.

The loose cover/dribbling fuel keeps housing pressure down, which (if the fitting/valve is clogged) will build up 'til the pumping plungers can't move outward to take on a new charge of fuel to inject, and the engine then dies.

mite-help · Sep 10, 2014

I bet this is a roosa master/standyne pump. these are bad about return line stopping up, usually due to internal failure. will act same way. bleeding anywhere will restart til pressure builds & stalls again.

ih_bug · Sep 10, 2014

do the fuel lines go in the top of the fuel tank or the bottom?
if they go in the top and you changed the line to the lift pump you still havnt looked at the line in the tank. is it cracked? fairly common problem.

Brendon Warren · Sep 10, 2014

I have a 302 as well. Sounds like your lift pump to me. Screen in the bottom of tank used the bother but you said you've been through it.

rpllr · Sep 10, 2014

if its a roosamaster rotary pump check the return fitting in the top cover of the pump, there is a check ball and spring in the fitting that will get rusted or stuck. file off the bottom of the fitting and take the small plate and ball and spring out. our 5020 would run a few minutes and die this fixed it.

Bob · Sep 10, 2014

rpllr, The crud in the fitting/valve is a sign that a plastic ring that separates metal parts/drives the governor has deteriorated from exposure to heat and diesel fuel and is breaking up.

You say you "fixed" it by "file off the bottom of the fitting and take the small plate and ball and spring out".

Well, if it is run long enough with your "fix" and the metal studs that drive the governor get worn off, guess what... there"s NO governor, and soon NO ENGINE!

Doesn"t sound like a very good
"fix" to me!

While no one likes the expense of having the IP rebuilt, it really needs to be done before the problem "accelerates"!

(Many board members here have successfully done the repairs themselves for about $30, but that"s not for everyone, and doesn"t repair any other issues that may be developing in the pump.)

morgan in ar · Sep 10, 2014

no, the fuel line comes out of the bottom. Thanks anyway.

morgan in ar · Sep 10, 2014

I'm not sure the type of pump, but it doesn't look like the roosa on my 3010, I'll have to check later. This is starting to sound like the problem, because after it dies, when I loosen the bleed off on top of the filter, fuel sprays out while it is not running. After this pressure is bled off, It will start. You may have me on the right track.
So, if I loosen the inspection cover it will relieve the pressure and it should stay running, pointing to needing the injector pump rebuilt?

mite-help · Sep 10, 2014

Had a mechanic buddy that used to carry a 'gutted' fitting with him to limp turbo diesel's off side of road-

Bob · Sep 10, 2014

"So, if I loosen the inspection cover it will relieve the pressure and it should stay running, pointing to needing the injector pump rebuilt?"

Yes, if it the common "JDB" pump, NOT sure if they used anything else during production, but that's all I saw in a QUICK look at the parts manual.

If it DOES run with the cover a little loose, pointing to a restricted fuel return system, BEFORE condemning the pump, make SURE the fuel return system is "open" all the way from the IP to the fuel tanks, as a restriction ANYWHERE in that line will cause the engine to shut down... could be as simple as a line that has gotten damaged/squashed.

JDemaris · Sep 11, 2014

You say itt doesn't look like a Roosamaster/Stanadyne?? It's all Deere used on USA market 302As. Fractured pellathane weight dampener in the governor, and a plugged housing-pressure-reguator-valve at the fuel exit is a VERY common issue. 3-4 hour fix and $50 in parts with the right person. My 300B loader-hoe Deere did the same last summer while a mile from home. I first took the ball and spring out of the fitting just to get home. Did NOT make it. Return boots on the injectors were also plugged shut. So I finally took the fitting out and let the fuel spill on the ground. Drove a mile home to my shop with a fire extinguisher in my hand. Got it into my shop and fixed in half-a-day.

morgan in ar · Sep 11, 2014

AWESOME. Great information thanks. That's the pump.

air in fuel system second try

morgan in ar

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RayP(MI)

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Frankmn

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mite-help

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ih_bug

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rpllr

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morgan in ar

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