So I recently purchased a 08 Midi. Overall nice machine. I have discovered when using it as soon as I start to put some decent load on it , it will bog down and stall out unless I let off. Runs normal at idle and goes right up to full throttle when not on load no problem. I drained fuel tank and flushed it, changed both filters. Blew the line back into the tank. Still same issue. Ran with Fuel tank cap off to see if vent was clogged same issue. I can hear lift pump pulsating when I key on. I have not tested fuel pressure yet. Any ideas?
-
Thank you for visiting HeavyEquipmentForums.com! Our objective is to provide industry professionals a place to gather to exchange questions, answers and ideas. We welcome you to register using the "Register" icon at the top of the page. We'd appreciate any help you can offer in spreading the word of our new site. The more members that join, the bigger resource for all to enjoy. Thank you!
2008 JCB Midi CX Stalling under load
- Thread starter JJM
- Start date
Tags
Senior Member
Are you talking about when using the loader or the hoe.
I believe that has a hydrostatic transmission. If it’s acting that way when using the loader it may be because it’s not in a low enough gear range or it can’t handle the load you are putting on it and you are overwhelming the hp available and it’s stalling because of it. If it’s doing it when really working the Joe then it may be a fuel problem.
I think those are only around a 40hp machine(?) very capable but it does have some limitations.
I believe that has a hydrostatic transmission. If it’s acting that way when using the loader it may be because it’s not in a low enough gear range or it can’t handle the load you are putting on it and you are overwhelming the hp available and it’s stalling because of it. If it’s doing it when really working the Joe then it may be a fuel problem.
I think those are only around a 40hp machine(?) very capable but it does have some limitations.
Actually no. It can occur when I use anything. The repetitive motion or heavy load will cause it to start bogging down and if I continue then it will stall out. Starts right back up. Idles perfect. It’s 50 hp Perkins. Very powerful when it’s got full power. You could do one motion with heavy load and for that moment it’s ok then soon as the load continues like halfway through the lift the rpm’s will start to fall.
it acts like a old school carb if the bowl was running empty. Not getting replenished fast enough.
HarleyHappy
Senior Member
Still may be hydraulic related.
What would cause that that’s hydraulic related ? Everything operates normally
HarleyHappy
Senior Member
While I don’t know anything about your machine, if it is hydrostatic on my Kubota when it is down on oil it will stall out doing normal things.
Going up a hill, using 3 point hitch too high.
Has great power but when trying to do certain things just stalls out randomly.
Starts right back up.
Finally figured it out when I raised loader up too high with a rake on the back while up it just stalled out.
Found out later my brother had blown a line and fixed it without adding hydraulic oil. Lol
Sight glass is a pain to see.
Going up a hill, using 3 point hitch too high.
Has great power but when trying to do certain things just stalls out randomly.
Starts right back up.
Finally figured it out when I raised loader up too high with a rake on the back while up it just stalled out.
Found out later my brother had blown a line and fixed it without adding hydraulic oil. Lol
Sight glass is a pain to see.
Tinkerer
Senior Member
When the rpm's start and continue to drop is the motor laboring hard when it happens ?
Or is it as if you were slowly closing the throttle ?
Or is it as if you were slowly closing the throttle ?
Yes it does seem likes it’s laboring or just running out of fuel. I do see some black smoke.
If I back off Rpm’s will rebound pretty closely to the original set point fast then slowly climb back to actual set point. Then act like nothing is wrong
it usually takes a few repetitive cycles or heavy loading to get it to bog down. Won’t happen on an initial run unless under very heavy load.
If I back off Rpm’s will rebound pretty closely to the original set point fast then slowly climb back to actual set point. Then act like nothing is wrong
it usually takes a few repetitive cycles or heavy loading to get it to bog down. Won’t happen on an initial run unless under very heavy load.
thanks I’ll double check fluid.
Tinkerer
Senior Member
Does it continue to do it if you stop using the hydraulics and put the transmission in neutral ?
If I stop doing anything with load it will come back up. I tried using loader , backhoe , stabilizer arms. Doesn’t matter what it is. If I put it under heavy load it will bog down and stall if I don’t let off.
That’s why I’m thinking it’s fuel related.
Tinkerer
Senior Member
My best guess is that the injector pump may have a problem.
I don't know about fuel injection pumps, but it kinda sounds like a governor not working like it should.
Or a simple thing like the throttle linkage is not holding the throttle open.
thepumpguysc will eventually read this thread and figure it out for you.
I don't know about fuel injection pumps, but it kinda sounds like a governor not working like it should.
Or a simple thing like the throttle linkage is not holding the throttle open.
thepumpguysc will eventually read this thread and figure it out for you.
So I did some more testing today and believe I have come to a conclusion. I removed the output fuel line coming from the the filter that goes to the injection pump. I installed my test port into the existing fuel port and hooked up to my fuel gauge to test the pressure of the lift pump. Key on get basically nothing 0-1 psi. I know lift pumps generally are 8-15 psi from my diesel experience. I started the the tractor and also ran it inline , same result 0 psi. I capped one port of the fuel filter and ran the other to my gauge so it had no where to return....same result 0 psi. So my conclusion is the lift pump is shot. I can hear it pulsating but maybe the diaphragm is shot and cant build pressure. There are no visible leaks from the fuel lines or anything so its not going anywhere. I opened the Schrader valve while running expecting to see a pretty steady stream of pressure and barely dribbling out . So I am going to order a new lift pump and see where we go from there. Will start right up and idle all day no problem. Under continuous load it dies out. I'm suspect its emptying the filter.
So here are some more updates. Installed new Lift pump, now it had some pressure. Previously read 0 psi. Now seeing 3-4 psi . Started to inspect all the lines. Discovered a pin hole leak right at the entrance to the lift pump outlet. Cut the hose back and reinstalled with new clamps. Leak fixed. Now pressure is around 6-7 psi. Started machine and ran. Seemed noticeable stronger and better. Let it warm up a bit then started to cycle the loader and stabilizer arms to get it loaded up. After cycling a bunch of times rapidly I can get it to bog down again though not as bad and not dying out. Definitely much improved but I feel not 100% unless this is just hydraulic loading ?
So here is my theory. One of 2 things is still not right. First when the previous owner had it, developed small leak on fuel line by lift pump. He didnt know or check and caused the lift pump to run dry and caused it to fail eventually. As a result this may have caused some premature wear on the injection pump and damaged it as well because it was running dry over and over again with lack of pressure. So as a result when machine is colder runs great even under load with very little change in rpm under load. As it warms up its not holding pressure and again is running out of fuel but not as much because lift pump is now keeping up. Next steps I am thinking to block the return line off while monitoring the fuel pressure and see if it builds. If it bleeds off then I know problem is in the injection pump not holding pressure. Thoughts?
Second theory is the hydraulic fluid was recently all changed and filter by previous owner. Possibly they used wrong fluid and viscosity is too thick not allowing fluid to return quick enough or pump fast enough and bogging down the pump?? Just a thought.
So here is my theory. One of 2 things is still not right. First when the previous owner had it, developed small leak on fuel line by lift pump. He didnt know or check and caused the lift pump to run dry and caused it to fail eventually. As a result this may have caused some premature wear on the injection pump and damaged it as well because it was running dry over and over again with lack of pressure. So as a result when machine is colder runs great even under load with very little change in rpm under load. As it warms up its not holding pressure and again is running out of fuel but not as much because lift pump is now keeping up. Next steps I am thinking to block the return line off while monitoring the fuel pressure and see if it builds. If it bleeds off then I know problem is in the injection pump not holding pressure. Thoughts?
Second theory is the hydraulic fluid was recently all changed and filter by previous owner. Possibly they used wrong fluid and viscosity is too thick not allowing fluid to return quick enough or pump fast enough and bogging down the pump?? Just a thought.