Problems starting my VW Quantum

I have a 1983 Volkswagon Quantum Turbo Diesel Stationwagon. I recently started having trouble getting it to start. When I turn the key, the engine sputters a couple of times, then just rolls over with no fire. After cranking for about 30-45 seconds it starts sputtering again and finally starts. Once the engine has started, there in no futher problem. If I shut it off for only a few minutes, it will start right back up. If I shut if off for 30 minutes or more, it doesn't want to start again as stated above. I talked to a mechanic about it, he seems to think it is a failed fuel line check valve allowing the fuel in the fuel line to loose pressure and bleed back into the fuel tank. When the key is first turned on, the fuel in the ignition chamber causes the engine to sputter until it is burned up. Then, the engine just cranks until the fuel line pressure is built back up allowing the engine to start. Does this sound correct? If so, where is this check valve, and how do I replace it? I welcome your comments. I also welcome any tips on fixing this problem.

Thank You
secretsquirrel55

Sounds like the pump shaft seal is worn and the pump is loosing it's prime after sitting a while. Severaal solutions here. (1) most expensive, replace the pump (2) replace the pump seal, under $10 and some work. (3) Put a small gasoline fuel pump up stream, going into, the fuel filter to help the pump get enough fuel. Wire it to the stop solenoid on the pump. Get one with the smallest volume and pressure possible. I've done options 2 and 3 several times. Two only works well when the bearing surface in the pump is good and yours is old. Option three is fool proof and gives you the preformance the car had when new by providing enough fuel to the pump. Extra fuel is simply returned to the tank.

Also make sure that the glow plugs are all working. If it cranks, blows whitish smoke, but won't start, it's getting fuel and it's not the pump seal. If there's no smoke, it's probably a fuel delivery problem.
To check the glow plugs, touch a test light to the bus bar that runs between the plugs, then turn the key on but don't try to start it. The test light should go on for a few seconds if the engine is warm, then go out. Don't trust the indicator in the instrument panel, as it runs off of the relay and not the plugs themselves.

My best guess is an air leak somewhere in the fuel system. Don't overlook the inter-injector return lines as a possible source of leakage. There is usually liquid fuel visible if they are weeping.

-Lee

Thanks, I'll try it out.

What's the compression pressure look like?