WTF! my pump return line is pressurised

[SMOKEYDUB]

OK i tried 2 different known good pumps and bothe are doing the same thing. The return line to the tank is getting pressurized from in side the pump. I have run the car with all of the injector return lines of and pretty well nothing comes out. But the on line that links the injectors to the pump is leaking out because the pump is pressurizing the small line. any ideas ? i changed the pump changed the injectors. I just dont know anymore. grrrr pls help.

[Maarten]

Plugged filter or line from pump to filter/tank?

[chrissev]

OK i tried 2 different known good pumps and bothe are doing the same thing. The return line to the tank is getting pressurized from in side the pump. I have run the car with all of the injector return lines of and pretty well nothing comes out. But the on line that links the injectors to the pump is leaking out because the pump is pressurizing the small line. any ideas ? i changed the pump changed the injectors. I just dont know anymore. grrrr pls help.

You might not get that much diesel out of the injector return ports depending on how you rev the engine.  If it is idling you won't get much usually.  Rev it up and some more should come out.  I had the same problem with my jetta before I replaced the cylinder head.  After head replacement, there were no leaks.  Near as I could figure it out, there was either a problem with the seal on the surface of the head that allowed high pressure compression from the engine to somehow get into the injector body and pressurize the return line, or the valve timing was somehow off and unusual pressure or negative pressure situations were taking place.  I never did understand exactly what happened, but the rebuilt cylinder head solved the leaky injector return line problem.  Before you go to that length however, you might want to do what I did originally to try to solve the problem, and that was to run a fish line through the return line to the tank to get any gunk out of it, and if that doesn't work run a second return line back to the tank to try to relieve the pressure.  You might just have a clogged return line.

[SMOKEYDUB]

its a rebuilt engine head to toe. so im going to replace the fuel filter tomorrow. and some new injector sheilds. it bothers me cause i ve been working so hard getting this engine together and its not going well in the fuel management area.

[QuickTD]

Make sure you are using a proper injection pump outlet bolt with the restriction in it. The bolt head should be marked "OUT". Some diesels (mk3's for sure) have check valves both the return and the feed line at the fuel tank, blow air down the return line to make sure its clear.