Bleeding fuel system?

[Carebear]

I changed the fuel injectors on my B7200 tractor, due to it would loose power after running for around 15 minutes. After I changed the injectors, tractor wouldn't start. Found information that the fuel system would need to be bled. Loosened nuts on fuel injectors, turned the engine over until air bubbles quit. Tightened the nut back, tractor started fine, but only ran for 2 minutes and quit. Did the steps again, still would only run for about 2 minutes and quit. Is there a step I'm missing?
Thanks for your help..

 

[85Hokie]

It sounds as if you have a restriction in the fuel supply line TO the filter OR the filter is not allowing fuel to pass.

Have you changed the fuel filter while doing any of this?

 

[Carebear]

It sounds as if you have a restriction in the fuel supply line TO the filter OR the filter is not allowing fuel to pass.

Have you changed the fuel filter while doing any of this?

Yes, I did change the fuel filter. There is a small thumb screw knob that I'm not sure if it should be open or closed? could that be the problem? I've tried both ways, doesn't seem to make a difference.

 

[GreensvilleJay]

not all diesels have the same fuel system or 'bleeding' proceedures but...
as a general 'rule', to bleed a system ,
you start at the first filter from the tank, bleed it( let air out),
then next filter.bleed it,
then finally bleed the injector pump.

if filters are clear plastic, you can see when they get full of fuel.

 

[Carebear]

Thanks, I'll try that sequence.

 

[85Hokie]

Thanks, I'll try that sequence.

Make SURE that the filter is completely full of fuel - WHEN you changed the filter- did you replace or place the new O ring in the housing?

 

[Carebear]

Make SURE that the filter is completely full of fuel - WHEN you changed the filter- did you replace or place the new O ring in the housing?

No, I did not replace the O ring, I'll check that too, thank you.

 

[85Hokie]

That O ring (lack of) will allow air to seep in and cause the problems you are describing

 

[North Idaho Wolfman]

There is a valve on the side of the injection pump, it's called a jet start valve.
you open it (left turn) to bleed the air out of the lines to the injection pump, then close the valve (right turn) .
Then you bleed the air at the injectors.

You can pull the small fuel line off the side of the jet start valve and see when it's got clean bubble free fuel coming out.
I put a piece of clear hose on it that I run back to the tank to purge it and make sure no air is in the system.
One other trick is get it running and crack each injector fuel line nut and you should hear it drop off then closing it will bring the cylinder back on line.

Where did you get the injectors?
There has know to be quite a few junk aftermarket injectors out there.

 

[Carebear]

There is a valve on the side of the injection pump, it's called a jet start valve.
you open it (left turn) to bleed the air out of the lines to the injection pump, then close the valve (right turn) .
Then you bleed the air at the injectors.

You can pull the small fuel line off the side of the jet start valve and see when it's got clean bubble free fuel coming out.
I put a piece of clear hose on it that I run back to the tank to purge it and make sure no air is in the system.
One other trick is get it running and crack each injector fuel line nut and you should hear it drop off then closing it will bring the cylinder back on line.

Where did you get the injectors?
There has know to be quite a few junk aftermarket injectors out there.

I bought the injectors on line from Amazon, I'm tempted to put the old injectors back on at least they ran good for about 1/2 hour before loosing some power, but the tractor kept running, just didn't have full power. I've tried every suggestion on bleeding the system, but nothing seems to work. I don't seem to have a bleeding valve on the side of the fuel pump, I do have a thumb screw knob from a fuel line exiting the fuel pump that shuts the fuel flow to the injectors.

 

[Carebear]

I checked the fuel filter to make sure it had the o-ring in it, and its there, so that doesn't seem to be my problem there.

 

[Carebear]

I've retightened all 3 injectors, bled each injector nut location, but still would not even fire.

 

[loggin]

I've retightened all 3 injectors, bled each injector nut location, but still would not even fire.

Unless I have missed something in the previous replies I don't think you mentioned if you have checked fuel flow to see if there is a restriction somewhere?

Also not sure if your tractor has a fuel lift pump but would be good to check as well.

Hope this helps!!

 

[MapleLeafFarmer]

Where did you get the injectors?
There has know to be quite a few junk aftermarket injectors out there.

I hear those stories around the coffee shop around here as well.
Guys getting ready for spring work so preventative changing out injectors and keeping old ones for emergency backup. Downtime is wickedly expensive versus cost of preventative maintenance.
Specifically guys have said the ordered what were marked as JD spec'd and bosch oem only to find out they were not only falsely labelled but didn't work as well.
bloody scammers / cheats.
Seems mail order has alot of poor quality scammy stuff these days.

 

[North Idaho Wolfman]

I bought the injectors on line from Amazon, I'm tempted to put the old injectors back on at least they ran good for about 1/2 hour before loosing some power, but the tractor kept running, just didn't have full power. I've tried every suggestion on bleeding the system, but nothing seems to work. I don't seem to have a bleeding valve on the side of the fuel pump, I do have a thumb screw knob from a fuel line exiting the fuel pump that shuts the fuel flow to the injectors.

#1 Amazon / eBay Injectors are almost allway junk out of ther box.
They either leak or they don't pop at the right pressure/ time.
Send them back and get a set from Oregon Fuel injection.

NEW INJECTOR, KUBOTA 15271-53020

IXC093500-1570

oregonfuelinjection.com

The thumb screw know is the Jet Start Valve (in Yellow)
It does not shut off fuel its a air bleeder valve.


The Red circle line is a return to the tank that bleeds fuel and air out of the lines and pump.
The Blue circle fitting and line are the suppy line to the injection pump.

 

[Carebear]

I hear those stories around the coffee shop around here as well.
Guys getting ready for spring work so preventative changing out injectors and keeping old ones for emergency backup. Downtime is wickedly expensive versus cost of preventative maintenance.
Specifically guys have said the ordered what were marked as JD spec'd and bosch oem only to find out they were not only falsely labelled but didn't work as well.
bloody scammers / cheats.
Seems mail order has alot of poor quality scammy stuff these days.

#1 Amazon / eBay Injectors are almost allway junk out of ther box.
They either leak or they don't pop at the right pressure/ time.
Send them back and get a set from Oregon Fuel injection.

NEW INJECTOR, KUBOTA 15271-53020

IXC093500-1570

oregonfuelinjection.com

The thumb screw know is the Jet Start Valve (in Yellow)
It does not shut off fuel its a air bleeder valve.


The Red circle line is a return to the tank that bleeds fuel and air out of the lines and pump.
The Blue circle fitting and line are the suppy line to the injection pump.

View attachment 120285

I ended up taking one new injector out and I compared it with an old one, the thread area was longer on the new injector! I put all 3 old injectors back in, the tractor started right away. So the new injectors had to be the wrong ones.

But now a new problem, tractor starts good, but it does not have the power to run in the fast speed gearing. If I put it on the low (tortiuse) speed it runs good but so slow, but as soon as I put it back on the fast (rabbit) it looses power and dies. Is there something I'm missing to do after putting in the old injectors? I did bleed the lines, no air bubbles. Just won't run well on high speed. In the low speed I get 2000 rpm, but not anything more than that. Any idea what this problem could be?

 

[North Idaho Wolfman]

It's really sounding like you have a fuel deliver issue to the injection pump.
or just really bad injectors.
Take the fuel line off the side of the injection pump and feed fuel to the injection pump from above via a bottle.
And see how it runs.
Crack the fuel delivery lines on each injector while its running and see if the RPM's drop the same on each injector.

 

[Carebear]

Finally found my fuel problem! After putting in the old fuel injectors, finding out the new ones I purchased were not correct, the tractor started right up. However, still no power in high speed, 2nd and 3rd gear. I then replaced the last 2 fuel lines, one to the injector pump and the other from the injector pump, and I had high RPMs, and no problem running in 2nd and 3rd gear with good power. Thank you so much for all the help in trouble shooting my fuel problem.