Fuel Return loom fails

[woodlandfarms]

Just was driving the PT around and smelling diesel. Thinking to myself what the heck is going on? Why do I smell like diesel? didn't fill the tractor.

Come to a stop, get off to look at something and notice a bit of smoke coming out of the engine. Lift the hood and there is a pool of diesel in the pan. Take the side cover off and there is a pinhole spray coming from the fuel line. WTF.

Thankfully Ken S suggested i buy a fuel return hose when he did. it is some crazy german size that only VW guys seem to have access to. It had been sitting on my shelf.

As usual, was intimidated but it was VERY easy. Less than 10 minutes to pull, cut new hose and replace. Old was was quite crapped out.

Here is a picture of the old loom. I guess this should be on the replace list for Diesel PT owners like once every 10 years or so.

 

[BobRip]

Thank God. A post on a PT!

 

[J_J]

Well, I guess nothing is broken or everyone's project is going or went well.

I been hanging out in the hydraulics forum lately.

Hope everyone is OK and having a good time.

 

[ponytug]

Dear Carl,

Is this a pressure distribution line, or a return to tank line, or used for both on your engine?

And the size is????
And you got it where?

Thanks for the pointers!

All the best,

Peter

Just was driving the PT around and smelling diesel. Thinking to myself what the heck is going on? Why do I smell like diesel? didn't fill the tractor.

Come to a stop, get off to look at something and notice a bit of smoke coming out of the engine. Lift the hood and there is a pool of diesel in the pan. Take the side cover off and there is a pinhole spray coming from the fuel line. WTF.

Thankfully Ken S suggested i buy a fuel return hose when he did. it is some crazy german size that only VW guys seem to have access to. It had been sitting on my shelf.

As usual, was intimidated but it was VERY easy. Less than 10 minutes to pull, cut new hose and replace. Old was was quite crapped out.

Here is a picture of the old loom. I guess this should be on the replace list for Diesel PT owners like once every 10 years or so.

 

[woodlandfarms]

It is a low pressure return line back to the fuel tank. There is a part of the loom that confuses me. It is the one that goes back to the engine. There is a T at the last injector toward the fuel tank that drops a line back into what I suspect, and probably wrongly so, is the fuel pump. I assume it is part of keeping the fuel in the high pressure line.

My notes from Ken S is that we bought 2.5mm ID line, but stock might be 3mm line. He found it on Ebay and turned me onto the provider. Neither Ken nor I have had any issue. I think it was a 2 foot roll

It should be noted that Ken replaced his due to a mouse moving in. Mine died out of old age.

Carl

 

[SpringHollow]

On the plus side, the diesel killed the mouse.

 

[ponytug]

Dear Carl,
I don't know how common it is, but I have seen a number of diesels recycle the fuel. I think that all of them used the diesel as the energy to drive the diesel injector and then the engine recycled the bypass fuel to the pressure pump. Since it was just used to drive the injection, the fuel is at low pressure. My logic was that the bypass diesel is the cleanest fuel that you have, so you would prefer to run it back through the system if you have a chance.

All the best,

Peter

 

[scrappy isb67]

Dear Carl,
I don't know how common it is, but I have seen a number of diesels recycle the fuel. I think that all of them used the diesel as the energy to drive the diesel injector and then the engine recycled the bypass fuel to the pressure pump. Since it was just used to drive the injection, the fuel is at low pressure. My logic was that the bypass diesel is the cleanest fuel that you have, so you would prefer to run it back through the system if you have a chance.

All the best,

Peter

all mechanical injectors use fuel pressure to operate( unless you are talking about HEUI or common rail) They open once fuel pressure reaches a certain pressure(commonly called "pop off" pressure)essentially they are a relief valve with a spray nozzle attached to them. There is no "control circuit" per se, if there was there would be more than 2 lines hooked to each injector and there would be no need for the injection pump with individual lines to each injector. That is how a Common rail system works but instead of using pressure, they are typically opened electronically.
The return fuel is just a return from the injector for excessive fuel that was not injected and/or leakage within the injector. the return fuel can be recycled back into the tank or prior to the fuel pump. returning it to the pump inlet can help with cold engine operation, I. E. using the already warmed fuel to warm the fuel from the tank to help prevent fuel gelling.