No fuel from return line to tank 3000 diesel

[Hardwood62]

Anybody have any idea of why there is no fuel coming from the return line to the tank? I remember it used to be a pretty good flow. The engine appears to be running rich but evens out when under load ... my son said it make his eyes burn. I have the CAV manual but can find nothing about the return circuit. When I loosen the banjo bolts on top of the injectors there is a good amount of fuel coming out, checked all the lines and there are no obstructions, removed the line from the pump and checked the banjo fitting with the metering hole and it was open ... what else do should I do? I am thinking that the excess fuel is being injested into the engine via the Thermostart connection in the intake manifold ... but have no idea of what to do next. I have replaced all the injectors, checked engine compression, pump appears to be putting out a good fuel flow to the injectors, replaced fuel filters in tank, remote and inlet and still is not running right. Any help would be greatly appreciated!

 

[sotxbill]

obvious question, have you made sure the line back to the tank is not clogged somewhere,, next there is a junction/tee, where is feeds the thermostart or manifold heater. Do you have a defective heater that is allowing the fluid to leak back into the intake manifold??? thus burning eyes and stinking? Note, This heater, cold start aid, thermostart...... is an option and not on all tractors. Have you checked and or changed the oil in the cav pump? (Caution, dont over tighten the three oil caps as they strip out very easily on the injector pump.)

 

[Destroked 450]

Take the fuel fill cap off and look in the neck, the fuel return tube stocked thru the side of the neck
Make sure the end of the tube isn’t mashed flat from fuel nozzle impact over the years
The thermostarts fuel valve is a spring wire the opens the valve when heated, if the return is pressurized it can force the valve open

 

[Destroked 450]

obvious question, have you made sure the line back to the tank is not clogged somewhere,, next there is a junction/tee, where is feeds the thermostart or manifold heater. Do you have a defective heater that is allowing the fluid to leak back into the intake manifold??? thus burning eyes and stinking? Note, This heater, cold start aid, thermostart...... is an option and not on all tractors. Have you checked and or changed the oil in the cav pump? (Caution, dont over tighten the three oil caps as they strip out very easily on the injector pump.)

There is not oil in a CAV pump, your thinking about the inline Simms pump

 

[Hardwood62]

Took out the thermostart - started tractor activated thermo.... coil turn red - fuel started to come out and ignited, thermo... was deactivated fuel flow stopped ... conclusion, fuel was not being injected into intake manifold while running causing a over rich condition. ??

 

[a49deere]

Took out the thermostart - started tractor activated thermo.... coil turn red - fuel started to come out and ignited, thermo... was deactivated fuel flow stopped ... conclusion, fuel was not being injected into intake manifold while running causing a over rich condition. ??

Was fuel being pushed before the point of thermostart with line unhooked?

 

[Hardwood62]

Kinda dribbling out.

 

[a49deere]

Kinda dribbling out.

So does it "Kinda dribble out" of the filler neck on tank?

 

[Hardwood62]

Yes

 

[Sean in PA]

The fuel lines that go to the banjo bolts at each injector are for the main fuel delivery to each injector. The excess fuel lines are separate. Check all of the lines involved in the excess fuel return, the line from the pump to injector #1 that is not the main fuel delivery line for that injector (it comes out of the side of the pump body rather than from the round housing at the rear of the pump), then the individual lines between the injectors, then the line from the third injector back to the tee for the thermostart, and then the line from the tee to the tank. Disconnect each line at both ends and blow through them to make sure that none are clogged.

 

[Hardwood62]

All lines disconnected at top of injectors and piece of trimmer line pushed through. Disconnected line at pump and was a continous small flow of fuel coming out when running - seemed to be much less flowing into tank but hard to determine exactly - would probably be best to insert small piece of hose in tank inlet to see if similar flow is present but sure doesn't look like it.

 

[Sean in PA]

Did you check the fittings under the banjo bolts at each injector that the excess fuel lines connect to for clogs?

 

[Hardwood62]

New injectors - fittings?? All return lines are open - banjo connections are good.

 

[a49deere]

I

New injectors - fittings?? All return lines are open - banjo connections are good.

I'm no injector specialist, but isn't there a pop off pressure? Is that correct on all your new injectors?

 

[sotxbill]

There is not oil in a CAV pump, your thinking about the inline Simms pump

Dang,, could have sworn it says CAV on the side (CAV-ENGLAND) JUST like the picture above. I keep getting confused.

 

[Destroked 450]

I’ve seen them say both ways CAV or Simms
However generally when CAV is mentioned it’s in reference to the common CAV rotary inj pump, and the inline pump is referred to was a Simms inline

 

[Sean in PA]

Yeah, the in-line pumps are generally called Simms or Minimec.

 

[Hardwood62]

I

I'm no injector specialist, but isn't there a pop off pressure? Is that correct on all your new injectors?

All injectors are new and tested at 2700psi +/15lbs prior to installing.

 

[Hardwood62]

My overall problem is excess fuel being injected into the engine - under load it appears to run near normal but otherwise it puffs blue-gray smoke and run erratically. Maybe not the return line but the fuel lines to the injectors seem to have sufficient flow and pressure when disconnected from the injector. Are the injectors to have 4 spray ports or something else? I have adjusted the timing approx one notch away from engine and it runs better at open throttle.

 

[Hardwood62]

The old injectors have England stamped on them ... does that make a difference. The one I purchased say not for tractors made in England but I have not been able to find any specifications on the differences and the OEM numbers match the ones I bought. One other thing - when I reduce the fuel control it doesn't seem to make any improvements, does slow engine - thought maybe reducing flow to pump would cut down flow to engine and give a leaner feed. Not sure what to do next, had pump overhauled about 5 years ago and tractor is only used for about 2 acres of food plots once a year - should not be bad already??