John Deere 755c Running issues No Power

[dieselman24]

We have an 02 755c (Liebherr made for John Deere) and it has never given a problem it now has 6000 hours on it and it has just been losing power for the last few weeks and it has now really got bad we were pushing up black dirt in a field friday and it just would power out. We changed the fuel filters 2 weeks ago and there was never any difference in the machine. All of the Hydro fluids and filters have been changed as well due to a blown line same time as fuel filters so it is all new as well.. I am a member on all ofhte Diesel Truck Sites and they are very helpfull so I can only expect this this site to be of the same family of folks.. We are in the st.louis area 573 202 9999 call or text if you need too.. Thanks Dieselman..

 

[willie59]

Have you checked for blockage of the fuel supply lines from tank? Blow back through fuel line to tank with compressed air? Have you checked that lift pump is moving fuel? Also, is the shutoff solenoid pulling fuel shut off lever to full run position?

 

[dieselman24]

Willie I did all of that today it had 40 pounds of fuel pressure and lots of volume I took the filters off and dumped them into a paint filter and there was nothing but red fuel, I guess we will take the pump off in the morning and run it up too Diesel Injection Service in St.Louis he said he can bench test it it for me while I wait and see what it is doing I do have a question though there is 2 sensors one on the side of the injection pump with one wire going to it and that wire was broke off last week but never affected the way it was running unless we never noticed it, and there is also another one that is on what looks like a return fuel line just above the inj pump. Also if I take the pump will it have to be retimed? the pump is slotted for the bolts but the shaft has a key way in it. I took the fuel shut off all the way off and zip tied it open ad run it for a few mins and it still would not hit the 6.8 mph that it is suppose to track its only going like just maybe 4 and it goes slower in Low range.. I sam just stumped on this one. We have a big job comming up maybe in the next few days loading 40k yards of fill for a new Kohls store that is going in town and gotta get the machine fixed or we will have to rent one until it gets fixed and thats cash out of pocket this one just got paid for like 15 months ago it always goes that way lots of work and now equipment broke down. . Thanks for any help..

 

[dieselman24]

Erb is Going to come down mid afternoon to chech ole sue for me, I called them this morning before I was getting started to pull pump off..

 

[Dickjr.]

I wonder if the turbo is making full boost. Had the same problem rigged up a boost guage and only had 7 lbs of boost . This is easy to rig. Drill or find a port on the intake and get some hose and a 30lb guage . You should have 20 lbs or more boost. Good luck.

 

[dieselman24]

Ok guys heres the deal Mike from Erb come down to the shop with his handy little Liebherr Scan Tool and found the problem in 10 mins it was fuel related but it could never have been found without the scan or I guess it could but it would be many hours of looking he hooked it up and found not enough power going to the Throttle Postion Sensor so it was shutting the fuel off to the injection pump so upon further inspection we found the wires going to it that were in the rubber gromett and in the Johndeere sheeth had wore through 4 of the 5 wires and the were all bare and shorting out so it had no idea what to do.. He spliced the wires all back together and vavoom it runs like a brand new 755c all kinds of power no power out issues at all and we had him turn up the RPM to 1995 so now it really runs good before it was only at 1775 tracks like a dream nice and fast now, we even got the a/c blowing ice cold today thats really good this was the best of the year so far it didnt cost an arm and a leg just about $400 for a service call.. Man it feels good to be able to sleep good tonight now I need to find a place to buy under carriage for it complete it will need it in the next 250 hours or so so if any knows where to get a good deal on it I would like to get rails and pads complete all painted everything also need it for our 750 dozer really bad, Thanks for all of the help and advice.. TJ (Dieselman24)

 

[Jeremy827]

Hey guys quick question, i have like a 04 jd 755c and it only will run in reverse (sometimes). If i get it to full speed then switch it forward it will sometimes work tho. if i just try to go forward it will turn the parking brake on, the low speed light, and the electrical problem light on. i dont know what to do first, i need the machine running asap. also if im pushing a big pile instead of slowing down it just stops and turns all the safety stuff on. Thanks! Jeremy

 

[Actioninc]

How do these 755c measure up to a 963c cat? I sold my 963B which was a great machine looking for something a little newer to keep operators happy....

Thanks

 

[paver626]

Hey did you ever figure out what was wrong with the John deere 755c I'm having a very similar problem