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General Forestry => Forestry and Logging => Topic started by: Brewin1808 on February 11, 2020, 04:00:22 PM

Title: John deere 648h fuel issue
Post by: Brewin1808 on February 11, 2020, 04:00:22 PM
So our 648h will start fine idle as long as you want putts around fine and then as soon as you start putting a load on it will start cutting out like its running out of fuel crazy part is if you shut it off for just a couple  seconds it will fire right back up.... And run fine until it has a load on the motor again
Title: Re: John deere 648h fuel issue
Post by: donbj on February 11, 2020, 04:27:25 PM
Fuel restriction? Plugged filters? Start with the simple things.
Title: Re: John deere 648h fuel issue
Post by: Firewoodjoe on February 11, 2020, 07:34:20 PM
I ran a 648h that had bacteria/elegy something in the tank. (So Deere said anyways) took the tank off steam cleaned and was fine. I'm not saying that's it but definitely sounds like fuel restriction.
Title: Re: John deere 648h fuel issue
Post by: moodnacreek on February 11, 2020, 07:58:17 PM
Some filters will only plug when fuel is being drawn. When stalled or shut down the stuff that is plugging the filter drops to the bottom of the can. When the engine is re-started the process starts over.
Title: Re: John deere 648h fuel issue
Post by: Brian_Rhoad on February 11, 2020, 08:27:43 PM
Check for rubber hoses. They get soft over time and can collapse when the fuel pump pulls more fuel under load. 
Title: Re: John deere 648h fuel issue
Post by: Corley5 on February 11, 2020, 09:01:00 PM
Filters first :)  Check fuel lines.  Could be the lift pump.
Title: Re: John deere 648h fuel issue
Post by: BargeMonkey on February 11, 2020, 09:25:47 PM
Blowing any smoke on start up ? 6068H EGR junk... I would go with filters but wouldn't rule out bigger issues. 
Title: Re: John deere 648h fuel issue
Post by: kiko on February 11, 2020, 09:44:35 PM
Any low fuel pressure warnings?  On the fuel filter with bowl, make sure the oring is in there between the bowl and bottom of filter.  On the filter that is located on the engine enclosure, there is a 90' fitting that will catch trash. I usually just remove the whole filter housing  assembly  to access the hose and that fitting because they are on the backside of that filter. Also take the fittings out and make sure there is not any trash in the filter head.  That is where you can also blow the supply hose back to tank esp if you find pine straw trying to make that 90'.
Title: Re: John deere 648h fuel issue
Post by: Brewin1808 on February 12, 2020, 12:51:06 AM
Thanks everyone for the replies I have tried almost all the suggestions I changed filters and have actually got stuff stuck in the 90 going into filterhead a few times before I replaced the fuel pump with the filterhead because of course John Deere sent whole assembly and the inlet line was stripped going into filterhead I blew through the line back to the tank and even pressurized the tank to check for small leaks that I could be sucking air from I guess there is  a relief  valve on the high pressure rail so I'm going to try that tomorrow because it makes sense to me that if it is opening under pressure it may not close until the pressure is back off has anyone ever heard of injectors coming right back like that or even an injection pump working like that 
Title: Re: John deere 648h fuel issue
Post by: Southside on February 12, 2020, 12:55:59 AM
My LBZ Duramax had a weak relief valve at the very end of the common rail, so yes I could see something like that being possible. 
Title: Re: John deere 648h fuel issue
Post by: Brewin1808 on February 12, 2020, 01:18:06 AM
And no I'm not getting any codes which is crazy but not unheard of I guess.... And it doesnt smoke really on startup and it has some kind of egr delete program 
Title: Re: John deere 648h fuel issue
Post by: kiko on February 12, 2020, 08:28:45 AM
Since I am not sure what you have already tried I am just going to go down the line. The orings in top of the filter heads that are in the engine need to be checked for leaks. All the metal lines on the supply side have rubber grommet and each must be checked.  The rail relief has a small line coming out of it, remove this line and start engine, there should be zero fuel comng out of the relief. Rail relief failure usually creates a no start condition. Also has anyone fooled with the high pressure pump as it must be timed. Make sure the return is clear to tank.
Title: Re: John deere 648h fuel issue
Post by: treemuncher on February 12, 2020, 02:53:43 PM
There was a post on Heavyequipmentforum.com regarding a JD 4045 engine with problems. One of the posters from Canada suggested the suction valve on the fuel injection pump would go and then cause the high pressure relief valve to fail. You will need to do a search to find it.

I found this recently because my 4045 was not attaining full rpm and was very low on power. I just purchased this piece so I had no history on it. Turns out my fuel injection timing was off and my camshaft was well past worn out limits. Still waiting on my parts to finish.