fuel leak at high pressure pump

[Terry Forshier]

Now that I am getting a full flow of fuel to the engine(1988 XP25) I find that I have a fuel leak at the top or first cylindeer on the fuel pump. It is seeping fuel just like the injector did before I replaced it and put in the compression seat washer.
I looked up the diagram in the manual and could see there is an O ring at the top of this system. Losening the
fuel nut on the copper tube that is the fuel line that tightens down on to the part that screws into the pump housing I slid this nut up and did not find an O ring. Is this where it goes?
I did then take out the threaded elongated piece that screws into the housing and exposed the spring and the nozzel, (I think it is a nozzel). I cleaned this up and put on teflon tape as the automotove supply place told me they use that on Mercedes fuel lines. Well I did that on both threaded paerts, bled the line and started up. Still leaked. (I did not find an O ring)
I suppose that since the fuel shut off value had been only partly open this was not a problem but now that I have full fuel flow I am seeping here. Any ideas?
Terry

[Terry Forshier]

Found the problem and fixed it. Terry

[Mike and Joanne Stimmler]

What was it Terry?

[Ron Hill]

Terry : Glad you fixed it, as I don't believe there is (or should be) any "O" ring in either end of the 3 metal tubes that go from the injection pump to the injectors.  The ends of that tubing should be flared and the nut tightened down for a compression fit on to the pump or the injector. 
I've had them all off at one time or another.

[Terry Forshier]

I guess I was not clear on the description of the system. If anyone is really interested you can see the expanded view in the parts manual under high pressure fuel pump.The O ring as indicated above was not on the fuel tubing connection system. It is located on the larger diameter piece that threads into the fuel pump housing. It is shown on the expanded view in the parts manual. When I unscrewed this piece and lifted it out of the housing there was no O ring. However, after I replaced  the part back in and then removed it again there was an O ring about halfway up the threads. It seems that at the top of the nozzel where the spring seats ther is a space between the spring and the housing. It is hard to explain but  I removed that system there is a very small and micro thin washer about 3/16 in diameter that sits on top of the inner part.. It was not in place but had slid off and was lying on its side in the hole alongside in that space. It was so small I could barely see it. . When the parts were screwed together the O ring would smash or peel or in the latter case, ride up the threads on this washer and this is what was making the space where fuel would leak out. Anyhow, to shorten this, I took off the O ring that was sliced but not in half, purchased a new O ring, seated the washer, tightened up the system and "wonders" it worked fine.

[ozzie]

Terry,

I am glad that you have got it figured out. The part that you are describing is the delivery valve (nozzle) and the delivery valve holder
( large round piece with a hex for a wrench ) The delivery valve holder should be held with a wrench when you loosen the injector line (fuel tubing) or you will create a leak. There is a clamp between the delivery valve holders but they can loosen off over time. Be carefull not to over tighten the delivery valve holder as it can seize the fuel injection pump plunger and you don't want to go there. It can cause all different types of problems. There should be a torque spec for the delivery valve holder. Also if you can help it don't use teflon tape on any high pressure fittings eg. injector lines as you can get tape gumming up the injector. On the low pressure pipe fittings a Permatex thread sealant paste with tefon works well.

Good luck,

Dave.

[Ron Hill]

Guys : For those of you that are changing an/all injectors you do NOT have to remove the fuel tubes between the injection pump and the injectors. 
All you need to do is back off the nut that holds the tube on to the injector.  Then gently bend the tube back just far enough to get a socket on the injector. 
As Dave pointed out, don't even screw with the nut that holds the fuel tubes to the injection pump.