Air Leak??

[Sonofaskipper]

Engine running. Oddly zero smoke when the video was taken. With the engine stopped the hose is completely charged. Do I have a massive leak downstream? Or could it be a bad fuel cap creating a huge vacuum?

 

[Eurasiaoverland]

Your explanation is not very clear - the engine runs, the hose is full when it stops. So under what condition are the pictures with the half full hose taken?

If you had a massive leak downstream, surely you would notice diesel dripping out?

If that was the before the engine ran after a filter change or other work involving opening the fuel system, and it remains full now, no issue.

If after some time the hose became half full, the fuel is running back to the tank, meaning you have an air leak somewhere between there and a higher point in the system, quite likely the primer/filter bracket assembly.

 

[Sonofaskipper]

Your explanation is not very clear - the engine runs, the hose is full when it stops. So under what condition are the pictures with the half full hose taken?

If you had a massive leak downstream, surely you would notice diesel dripping out?

If that was the before the engine ran after a filter change or other work involving opening the fuel system, and it remains full now, no issue.

If after some time the hose became half full, the fuel is running back to the tank, meaning you have an air leak somewhere between there and a higher point in the system, quite likely the primer/filter bracket assembly.

No noticeable leaks anywhere. Still taken with the engine running at idle. Filter housing is new. Been chasing this for a while. Doesn’t run rough. Starts right up. Have had issues with white smoke on start up and at idle in traffic.

 

[Sonofaskipper]

No noticeable leaks anywhere. Still taken with the engine running at idle. Filter housing is new. Been chasing this for a while. Doesn’t run rough. Starts right up. Have had issues with white smoke on start up and at idle in traffic.

Hose is completely full after shut down.

 

[Squash]

I would try putting the hose into a jerrycan of fuel and see if there is a difference. Tie a weight to the hose end to ensure that the end stays covered in fuel.
Start at the pump and work towards the tank item by item. Lastly with and without fuel cap, you would need to have the engine running long enough with the cap on tight to be noticeable. At this point maybe the return line can be examined.

 

[Sonofaskipper]

I would try putting the hose into a jerrycan of fuel and see if there is a difference. Tie a weight to the hose end to ensure that the end stays covered in fuel.
Start at the pump and work towards the tank item by item. Lastly with and without fuel cap, you would need to have the engine running long enough with the cap on tight to be noticeable. At this point maybe the return line can be examined.

This is solid advice, thank you!

 

[Eurasiaoverland]

As I see it, if it sucks air in only when running, and does not leak fuel when stopped, it must be upstream of the pump.

Is that clear hose the stiff polyurethane type? If so, it may be the culprit. Also, those screw clamps are particularly bad on small diameter hoses (Toyota does not use them) as they do not provide even clamping force around the hose and tend to deform the hose, particularly when they are overtightened to stop leaks.


How are the metal lines in the tank pipe stack?

 

[Sonofaskipper]

As I see it, if it sucks air in only when running, and does not leak fuel when stopped, it must be upstream of the pump.

Is that clear hose the stiff polyurethane type? If so, it may be the culprit. Also, those screw clamps are particularly bad on small diameter hoses (Toyota does not use them) as they do not provide even clamping force around the hose and tend to deform the hose, particularly when they are overtightened to stop leaks.


How are the metal lines in the tank pipe stack?

I’m out at work now, but the clear hose is temporary to identify the air leak. I ordered proper fuel hose clamps. Will be inspecting everything upstream of the filter housing/pump when I get off the boat next week. Will report any findings