Losing Power...

[Atlanta Panther]

Was just tooling along dragging my arena when all of a sudden I'm losing power on my L3200HST. It will not go over 1500rpm now...almost like I lost a cylinder. I limped back to the Pole Barn where its sitting awaiting a diagnosis and repair. Fuel Bowl is full so I don't think its that.

Any suggestions for this unskilled mechanic?

Thanks!

 

[D2Cat]

How many hours since the fuel filter has been changed, or the air filter? Pull your air filter to be sure it's clean, since it's easy and cost nothing.

 

[Jim L.]

Like D2Cat says, 1st check air filter and fuel filter.

Three things must be there: Fuel, air, and compression.

From the throttle along the rod to the engine on the right side, are the nuts on the threaded rod tight?

Try loosening the fuel cap to see if you have a blocked fuel vent preventing fuel flow.

Compression: Glow plugs and injectors tight?
Any over-temps that would cause the head gasket to develop leaks?

Any fuel spilling out around the injector lines terminations?

All the easy visual stuff that I can think of now... so good luck.

 

[North Idaho Wolfman]

Fuel filter bowl can be full and the filter can be completely blocked.
Pull it off and check it's condition.
Do the same for the air filter to.

 

[Atlanta Panther]

Air filter and fuel filter are clean and gas cap is free of debris. I don't see leaking anywhere so I'm working on the theory that there is a blockage somewhere. One thing I found that I had not done the last time I cleaned the fuel filter bowl was bleed the fuel line. The manual says to open this valve for not more than 30 seconds but does not say whether to do this whether the engine is running or not. I did this without the engine running but it made no difference. I then did it with the engine running and it seemed to help for about 10 minutes or so and then the problem returned. Other threads suggest there might be algae in the fuel so my next move is to drain the tank and blow out the fuel lines. I'll then strain the diesel and add a Biocide.

Any other thoughts?

 

[Atlanta Panther]

One more thing...I notice that sometimes, especially when the engine revs back up, some white smoke will come out of the exhaust. Might that be water contamination getting burned off?

 

[200mph]

I'd take the time to clean the fuel system and verify all connections are tight to ensure the fuel system to the pump is 100% operational. If it doesn't cure your problem it will help narrow the scope of where to look. The upside is that this work can be done at home for minimal cost, but it will consume your time.

There have been times I've taken the fuel tanks out (after draining all fuel) and cleaning the inside of the tanks to ensure they were 100% OK. Of course they need to be dry before refilling with clean fuel.

The scope of the fuel system I'm talking about is Tank to fuel filter outlet.

Good luck and report back what you find.

 

[North Idaho Wolfman]

One more thing...I notice that sometimes, especially when the engine revs back up, some white smoke will come out of the exhaust. Might that be water contamination getting burned off?

Have you checked the radiator?

 

[Atlanta Panther]

Re: Losing Power...UPDATE

So I drained the fuel tank and blew out the following lines with compressed air after disconnecting them at both ends:

- tank to fuel filter
- fuel filter air vent to tank
- fuel filter to fuel feed pump
- the injection pump air vent (I think) to tank (definitely a line that runs to the tank)

Note that I only see three lines to the fuel tank...not the 4 that they show on page 1-M2 of the workshop manual. I did not disconnect either of the lines that run to where the air bleed is located. They have screws as opposed to the normal clip clamps. I didn't want to mess with them unless absolutely necessary plus one leads to a location on the middle of the top of the engine that seems a little difficult to get to. By the way I think the shop diagram is not very clear.

I also changed out the fuel filter.

Just to make sure I don't have an issue with the radiator I filled the coolant level up to the max line since it was about 1/2 way down.

I put about a gallon of fuel from a different container in and now I can't get it started. The clear fuel filter bowl does fill up with diesel but I'm a little out of ideas right now. I noted that the little spring valve at the bottom of the fuel filter housing seems to work fine.

Couple of questions:

Since the fuel system was empty, how long does it take for the fuel to get to the injection nozzles so you can get an engine going. It seems to try to start but almost immediately doesn't continue firing.

Is the fuel bleed valve supposed to be opened for 30 sec with or without the engine running?

Any other suggestions?

 

[200mph]

Here's what my Grand L40 WSM states:

Bleeding Fuel System

Air must removed :
1. When the fuel filter or lines are removed.
2. When tank is completely empty.
3. After the tractor has not been used for a long period of time.

Bleeding procedure is as follows.
1. Fill the fuel tank with fuel, and open the fuel shutoff-valve (1).
2. Open the air vent shutoff-valve (2) on the fuel injection pump.
3. Start the engine and run for about 30 seconds, and then stop
the engine.
4. Close the air vent shutoff-valve.

IMPORTANT
***8226; Always close the air vent shutoff-valve except for bleeding
fuel lines. Otherwise, engine runs irregularly or stalls
frequently.

 

[North Idaho Wolfman]

Re: Losing Power...UPDATE

Just to make sure I don't have an issue with the radiator I filled the coolant level up to the max line since it was about 1/2 way down.

This is the second time I've read someone say what you have said, his case the radiator was empty and head was cracked.

Do not check the coolant level at the overflow bottle, it being full doesn't mean squat, take the radiator cap off and check the actual radiator level.

I'm betting you find it low or empty, if you do you have issues!

As far as the fuel issue, you need to follow the bleeding procedure in the manual, air will ne bleed out and it won't bleed itself!

 

[Atlanta Panther]

Re: Losing Power...Another Update...

So, I just happened to see Vic's video on bleeding the fuel lines...wish I would have seen it earlier...maybe it would have saved some problems...or at least some time. The video is here:

http://www.orangetractortalks.com/2008/11/how-to-bleed-kubota-fuelinjector-lines/

The pertinent section is as follows:

"Loosen off the retainer ring holding the fuel filter bowl in place, so fuel washes over the sides of the plastic cup. Tighten it up, as the fuel is flowing to eliminate an air lock on “top” of the fuel filter. Next, disconnect the fuel line coming from the fuel filter bowl, into the fuel pump. Confirm that fuel flows there. Reattach, and then disconnect the fuel hose coming from the fuel pump to the banjo fitting at the bleed screw on the injector block.
Crank the engine and verify you have fuel coming from the fuel pump."

So as I was following is step by step that he illustrates 1/2 way down the comments section. I determined that:

- fuel was flowing by gravity to the filter bowl,
- fuel was coming out of the filter bowl and into the fuel pump

When I disconnected the line that runs from the fuel pump to where the bleed screw is, I cranked the engine several times to see if fuel was coming out of the fuel pump. What would happen is that I would get a fairly continual drip but it would not "shoot out" as I would expect Consequently, I could see where it would take a long time to get up to the injectors. Is this normal or should the fuel pump really shoot out the fuel assuming its getting a constant flow from the fuel bowl which it appears to do. I just want to make sure I don't have a fuel pump problem.

Thoughts?

BTW, in response to the suggestion above, I did check the radiator and it was full so (fingers crossed) I don't have a head gasket problem.

 

[Atlanta Panther]

Re: Losing Power...Another Update...

OK...so I got the tractor up and running again by getting all the fuel lines bled, mainly by cracking open the top of the injectors until fuel sprayed out. The only issue now is that the tractor's engine still surges occasionally which I'd like to get resolved. The dealer suggested using a high quality diesel injector cleaner in the tank. He said it should only take 15-20 min of running for the diesel injector cleaner to get through. I got both Seafoam and Lucas. Any suggestions on which to try first or other suggestions? I'll let y'all know how it goes.