Air In Fuel Line

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Eloco

Well-known member
Joined
Jan 31, 2015
Messages
73
Last week I started getting a loud diesel knock from engine and when you press the throttle at a junction nothing until it has thought about it for a few seconds. Which is not good when there are people behind you at roundabouts! Did a bit of investigating yesterday and put a clear hose before the filter and can see air bubbles. I have looked the full length off the fuel line and cannot find a damp patch anywhere, even had the sender unit out all seemed fine. Has anyone had similar problem or any thoughts would be much appreciated.
 
A poor fitting seal on the fuel filter or the primer unit on top of the filter could be possible causes.
 
A poor fitting seal on the fuel filter or the primer unit on top of the filter could be possible causes.

I fitted new filter yesterday as my first thoughts. I have fitted the clear hose before the filter so the bubbles look like they are coming from before housing. Thanks anyway.
 
pin hole big enough to let air in under suction but not big enough to leak fuel is not uncommon, just replace the whole length in plastic, half hours work, Rick
 
pin hole big enough to let air in under suction but not big enough to leak fuel is not uncommon, just replace the whole length in plastic, half hours work, Rick

When you say plastic what sort of tubing do you mean :nenau
 
When you say plastic what sort of tubing do you mean :nenau

I have loads of used plastic pipe that they use in drinks Python (carries the syrup up to the dispenser at the bar) but your product is better, Rick
 
Think theres a download on this job too. Bet the old metal pipe is corroded above rear axle.
Front to back best idea though rather than just part. Also I've not done it but I do know that it's a messy job.
 
All depends on who's driveway you do it on.:augie:sly
 
Think theres a download on this job too. Bet the old metal pipe is corroded above rear axle.
Front to back best idea though rather than just part. Also I've not done it but I do know that it's a messy job.

Cheers for heads up on the link. :thumbs
 
Cheers for heads up on the link. :thumbs

I recently did my fuel lines, front to back, feed and return. If you are doing one, you may as well do both, as the rot will be in both.

It wasn't too bad on the mess front, I put down a load of corrugated cardboard and rags, and whilst I got rather diesel soaked, I didn't get any on the wife's stable yard.

I did a little thread on it, with a link to my supplier. Quick, cheap and good quality.

I think my thread was titled "mahoosive diesel leak". Took an afternoon to do it all.

Very rewarding and a good investment.!

:)
 
if you disconnect the pipes engine end and blow down them (mouth/bike pump etc) then you will push 99% of the fuel back into the tank and very little will remain in the pipes, Rick
 
if you disconnect the pipes engine end and blow down them (mouth/bike pump etc) then you will push 99% of the fuel back into the tank and very little will remain in the pipes, Rick

Good call Rick, the project car has the fuel lines as an advisory so it'll be on the to do list.
 
I would just replace them once and for all, I had a similar problem on my last Terrano and just left it get worse. Then suddenly out of the blue I had fuel dribbling from the metal pipes at the back. :eek:

Then I had to do the job straight away and realised I had been loosing a load of diesel whilst going along. :eek::eek:

Not only that but it was on the drive as well!!! :eek::eek::eek::doh
 
Just ordered feed and return pipes 10 and 6mm 10mtrs of each. Thought the same while I'm getting down and dirty may as well do them both. Hopefully sorts out the bad running give everyone an update when fitted.
 
A poor fitting seal on the fuel filter or the primer unit on top of the filter could be possible causes.

Good shout on the primer unit. After finding air in the feed pipe to filter I replaced that with rubber straight through, bubbles in feed gone sorted so I thought. I then transferred my clear pipe to after of the filter to find it looking like a fish tank feed. Fiddled with pump top and bubbles increased so I did a straight connection bypassing filter ran as it should no knocking or blue smoke. Now just have to source replacement primer pump.:thumb2 Thanks for your time and input last night Banshee.
 
Hang on to the replacement fuel lines. If they're not leaking now, it probably won't be too long!

Both my T2's went at the same age.

:D
 

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