1999 DT140 EFI runs great then sputters and dies

[bingsbait]

I have a 1999 DT140 EFI that starts and runs great, but at 3K RPMs and above the engine runs great and then it will sputter and if I don't throttle back fast enough, it dies. If the motor shuts off, it starts right up or if I can throttle back fast enough after about 5 seconds I can throttle back up and run until it happens again. The faster the RPMs, the faster the motor will splutter and die. At 3K it takes about ten minutes and at 4K it takes >5 minutes.

I have replaced the plugs, fuel filter, fuel bulb and fuel lines to the fuel pump, and still have the same issue. When the motor shuts down the fuel filter is full and the fuel bulb is solid and the block is warm but not hot. I get no warning lights or alarms.

I read that a vacuum line may be kinked, but I'm not sure where they are located.

Any help would be appreciated.

[Solarman]

runs then sputters, dt140efi

Sounds like a problem in the vst float area. Some trash in the needle valve, or sticking half shut?

[bingsbait]

Thanks for the reply. That seems to be the direction to go, but the VST may be out of my league. I'm taking to a mechanic tomorrow.

I will post results for future members use.

[Solarman]

if trash is in the vst, our the next place to look...

Have the Mech check the low pressure fuel pump (located right near the fuel filter bowl), the little check valves (not available that I know of) have been causing problems for many of us.

[bingsbait]

Here are the results. The vst filters needed to be cleaned and the low pressure fuel pump was also bad.
Thanks for your help,
Bing

[Solarman]

runs then dies.

Let us know if it runs ok when done.

[Solarman]

dt140efi

There is also a small cone filter that goes to the high pressure pump, and another high pressure filter going to the pressure regulator. Check your manual and clean those as well. The cone filter is at the bottom of the vst.
Keep us posted on how it turns out for you.

[POCJETTY]

There is also a small cone filter that goes to the high pressure pump, and another high pressure filter going to the pressure regulator. Check your manual and clean those as well. The cone filter is at the bottom of the vst.
Keep us posted on how it turns out for you.

I don't see the filter you mention (to the pressure regulator) on any parts explosions. Do you have any reference, or a part number? I hope you're right, and there really is another filter before the injector.

I've got an engine doing the same thing. The filter before the vapor separator was torn (as well as full of trash), and let a lot of gunk through into the VST. If there is a filter farther down the line, maybe it's clogged. If not, I suspect the injector is going to be clogged, which is more of a problem.

I'm also trying to figure out where all the junk came from. The only place I can think of is that the fuel line coming out of the low pressure pump is breaking down.

[Solarman]

dt140EFI, 99, runs then dies

Sorry the high pressure filter is before the fuel rail.the regulator is after the rail on top.

The small cone filter is located at the bottom of the vst - inline, this supplies fuel to the high pressure fuel pump. From the high pressure pump it goes through the high pressure filter, before it goes to the bottom of the injector rail. The regulator is at the top of the rail. The high pressure pump feeds the bottom of the injector rail.

If you have trash getting into the vst, you should inspect the low pressure fuel pump, and should replace all the fuel lines after the filter bowl. You should also check your water separator and clean/ inspect the filter bowl assy.

When cleaning the vst, make sure you remove the needle valve seat to clean the back side. Any trash or pieces of debris found in the system try to identify. If small pieces of clear plastic are found, then your low pressure fuel pump check valves are probably breaking up and will block the needle valve in the vst. If black particals, probably insides of fuel lines deteriorating, usually from user of ethanol fuel. Should replace all remaining old fuel lines all the way to the tank(s).
Good luck, let us hear how it's going.

[Solarman]

I don't see the filter you mention (to the pressure regulator) on any parts explosions. Do you have any reference, or a part number? I hope you're right, and there really is another filter before the injector.

I've got an engine doing the same thing. The filter before the vapor separator was torn (as well as full of trash), and let a lot of gunk through into the VST. If there is a filter farther down the line, maybe it's clogged. If not, I suspect the injector is going to be clogged, which is more of a problem.

I'm also trying to figure out where all the junk came from. The only place I can think of is that the fuel line coming out of the low pressure pump is breaking down.

POCJETTY, I understand you're looking at the same thread, but it would be better for you to start a new thread showing your motor and your problems. You may have a different need/ problem from what you're saying.

[POCJETTY]

Thanks - exactly what I needed

Sorry the high pressure filter is before the fuel rail.the regulator is after the rail on top.

The small cone filter is located at the bottom of the vst - inline, this supplies fuel to the high pressure fuel pump. From the high pressure pump it goes through the high pressure filter, before it goes to the bottom of the injector rail. The regulator is at the top of the rail. The high pressure pump feeds the bottom of the injector rail.

If you have trash getting into the vst, you should inspect the low pressure fuel pump, and should replace all the fuel lines after the filter bowl. You should also check your water separator and clean/ inspect the filter bowl assy.

When cleaning the vst, make sure you remove the needle valve seat to clean the back side. Any trash or pieces of debris found in the system try to identify. If small pieces of clear plastic are found, then your low pressure fuel pump check valves are probably breaking up and will block the needle valve in the vst. If black particals, probably insides of fuel lines deteriorating, usually from user of ethanol fuel. Should replace all remaining old fuel lines all the way to the tank(s).
Good luck, let us hear how it's going.

POCJETTY, I understand you're looking at the same thread, but it would be better for you to start a new thread showing your motor and your problems. You may have a different need/ problem from what you're saying.

Thank you for both replies. Sorry for not knowing the site etiquette. Some places get upset for starting new threads when a similar one already exists. I will know in the future.

For the record, my engine is a 2000 DT140 EFI. It starts easily, idles well, and runs like a madman - for about a minute. Then it bogs and goes down to basically an idle, even with the throttle wide open. Usually it dies, then it can be immediately re-started, and will immediately run wide open again - for about a minute. I felt like it was fuel related, but it helps to know all the things to look for, so I only have to tear it down once.

As it happens, the first response was precisely what I needed. So far all the debris has been dark, but I will know more when I break it all down. Your advice for replacing the internal lines, and checking the needle valve seat were helpful. I was debating replacing all the fuel lines, but your comment convinced me. If the internal lines are breaking down, the ones to the tank probably are as well.

I am feeling pretty confident that this is the problem, based on what I've seen. But I will make a point of following up and leaving a record of whether this actually fixes the problem. Since I've gone this far in this thread, I will put the response here to try to give it some closure.