Mystery Solved

[paradiceau]

Hi all,

I thought I would add this and hopefully somebody will benefit from it.....

I have a Samurai with a 1.9 TD in it, I am somewhat new to the diesel community and don't know all of the VW variants and details....

The pump was resealed several months ago and shows no signs of leakage....

My problem was, when driving the engine would suddenly hesitate, stumble and sometimes, (not always quit running)....

I had also replaced the fuel tank not long ago and fuel filter and felt my fuel system was pretty clean.  I thought maybe there was something floating in the fuel tank like a random sticker or piece of paper and occasionally blocking the fuel line inlet....  The tank is a bummer to pull and I did not want to do that if not necessary.   I also considered the electrical power to the fuel solonoid is somehow intermittent, and that is not too difficult to see...   

We ended up putting a vac. pump on the line just at the inlet to the filter and sucking fuel to it, when we did that there was a lot of air visible in the clear tubing and the clear vessel on the pump.  We replaced two sections of rubber fuel line, a six inch long section near the rear and a longer vertical section from down on the frame below the filter up to the filter...  After replacing those sections of hose and retesting with vacuum no air bubbles were visible in the clear lines and the engine sounds good and runs well....

I found it interesting that there was no evidence of a fuel leak anywhere in the fuel supply system even though there was a small crack in the hose or hoses allowing air to enter the system....  I reckon it is easier for air to be drawn into the line rather than pull fuel from the tank.... 

I was puzzled by this problem and am very happy it was so simple to diagnose and correct.....  I am sure some of you already knew this but hopefully some will benefit....

Great forum with lots of knowledge here, thanks all,

Jeff

[vanbcguy]

Glad you got it sorted! Yep, since the supply line is under vacuum it tends to pull air in when it leaks rather than letting fuel out.

You'll probably want to get yourself some clear supply and return lines to the pump when you can. They will make your life MUCH simpler down the road. Most VW diesels had them new from the factory. Really helps diagnosing issues like this.

[paradiceau]

Vanguy,

Thanks for the response, I have not visited this thread since I posted...  I think you have a good idea there and hope some other hapless individual has also benefited from this info!!!!

Best,

Jeff