Air bubbles in fuel line and cutting out

[Paul773car]

Hi all I need some help.

84 1.6d runs fine then all of a sudden loses power, when I open up the engine cover I see air in the lines. If I blow down the fuel pipe and reconnect it she works fine again for a few miles then the same thing happens again. So I have already replaced the fuel lines from the pump to the filter and the filter to the tank with clear lines. When it starts to stumble I can clearly see bubbles coming out of the tank outlet so I'm confused as to where the air is coming from as it's definitely not the fuel line leaking. Its like it's a leak within the tank but I don't get how air would get to the fuel outlet as it's on the bottom of the tank?

Any help appreciated. I'm at my wits end with it and the whole family now refuses to go anywhere in it.

Thanks

Paul

[colinthefox]

What hose clips re you using? Jubilee clips can distort the hose causing leaks. Fuel hose clips are the ones to use.

Is it possible that there's rust debris in the tank partially blocking the outlet? If this happens the pump will be sucking harder, so the hose joint at the tank might then be letting in air, and it would look like it was coming out of the tank. Blowing down the pipe would temporarily clear it.

As the air can't be coming out of the tank it must be coming from that joint.

Another possibilty would be that tank breathers are blocked, so after driving for a while suction builds up in the tank. I have had this before on another vehicle. A blob of s**t on the breather blocked when it got wet!

 

[Paul773car]

Hi I'm using small jubilee clips but I don't think it's that as the pipe is a really tight fit on the outlet even without the clips. I did think it might be debris blocking the line in the tank but with the bubbles i don't see how it could suck so hard that I'd get air in the line at that joint when it takes me a good 5 mins of twisting and pushing to get the line on the outlet. It's really tight.

Might just buy a new tank and see if that cures it or drain and clean this one. I take it there's no internal pickup pipework in the tank that leads to the outlet?
For now I'll remove the jubilee clips and see if it helps. The line is a right pig to get on so it's not gonna come loose without it.

Thanks

Paul

[muttleypup]

You could try running it off a separate fuel supply (jerrican) instead of the tank, if it runs fine this would at least give you a better idea on where the problem lies

[Paul773car]

Never thought of that. I have a tank for the heater so will try tomorrow.

I suppose it's gotta be the tank is full of crap though so when I get the chance will get it out and have a look

[Paul773car]

Update. I cut the end off that fitted to the tank. Added a joint and went with a slightly larger bore pipe onto the tank. Took the van out this morning and did 40 miles with no issues. Can only assume given how tight the pipe was that I must of damaged the end or something.

That said it's done this before then returned a few days later. Let's see.

[colinthefox]

Thanks for the feedback. It helps us all. Hope it's sorted for good now.

[Paul773car]

Quick update on this. Seemed to go away for a while then started happening again. I swapped the return and feed lines on the tank and replaced the return line with new fuel line. Issue seems to be solved. I think the tank will need replaced but for now as long as I don't let it get down to lower than 1/4 tanks she runs perfect