Air in fuel supply line - first 10 gal in tank usable

I have a 2001 Jetta TDI with 290K miles on it.

I have been having this problem for the last 100K mi but learned to live with it.

Im now thinking about giving the car to my niece - and want to fix it before I give it to her.

Only the first 10 gal or so in the fuel tank are usable - the guage reads correctly. At between half and quarter tank mark the engine will die from fuel starvation - I've been burned by this every six months. Fix for me is a 5 gal can of diesel in the trunk and a 17 mm wrench to "crack" the injectors and bleed the system (I know it's self priming, but this is MUCH easier on the starter). I believe that the fuel guage is accurate as I am only putting ~10 gal in when this happens - and have gone ~400 mi - so things seem to be reading correctly.

Symptoms are air bubbles in the line from the fuel filter to the injector pump. I originally thought it was due to o-ring leakage at the fuel filter, but I replaced the filter with an older one (same as my 1988 Jetta diesel) that does not have the return line going into the filter - and put a tubing connector on the return line - bypassing the "fuel preheater"

The problem did not go away. Where are possible places to look for a cracked fuel line from the tank to the fuel filter?

I used to be able to go 600 mi on a tank and kinda want to fix this before my niece gets stuck by the side of the road!

Thanks in advance

Tim

OK - pulled the access plate under the rear seat. Undid the Mason Jar type retaining ring holding the "fuel delivery unit"

Is there any trick to removing the fuel lines from the unit? Afraid to break them!

Thanks in advance,

Tim

I would check the pick-up in the tank given the symptoms you are seeing. Sounds like a crack in the pick-up that sucks air as soon as it is exposed when the tank gets down below half a tank. Access is under the back seat and you would want to look at it with the tank as low as you feel comfortable to avoid possible splashing issues.

Dave

This is a fairly common problem with the pickup unit in the tank. There is a hole in the pickup tube partway down which allows it to suck air once the fuel level reaches the hole. It may be possible to do a patch on the tube, but most people who have this happen replace the pickup unit. It is not a difficult job, but it can be messy dealing with fuel at the access panel under the back seat. This is the part you need. http://www.metalmanparts.com/product.sc?productId=581&categoryId=-1

Paul

Thanks!

What's the secret to removing the fuel lines from the pickup unit?

Timbo1080 said:

Thanks!

What's the secret to removing the fuel lines from the pickup unit?

Click to expand...

Simply squeeze the line at the end and it pops right off, no trick (for a change), only tool you need - fingers