question on sticking plunger in a d4 7u pump.

I had two plungers stuck on my 7u pump. Have been using pb blaster and atf acetone mix for several weeks and was able to get one to start moving. still have one stuck. I have tried slight pressure with a screw driver and tapping with a small 2oz hammer so as not to mess up adjustments. nothing working so far. If I pull the injector line and use air pressure to push the plunger down what can I mess up?? Will it even work. have been trying 3-5 times a day with no success. Any help would be greatly appreciated. Thanks in advance.

best way to loosen these pesky plungers is to very gently tap down on the lifter face--DO NOT try and tap the rack back and forth or you risk turning the plunger quadrant gear on the plunger and so losing the factory delivery volume setting.

After you get some plunger movement, turn the engine and allow the fuel pump lifter to raise the plunger--tap down gently again until the plunger rises and falls by itself then you can risk moving the rack gently.

There is a check valve between the fuel line connection and the top of the plunger so blowing air in there will get you nowhere.

Hope this helps.

Eddie B.

I have been spraying from the bottom side up to the plunger. It does look like it wants to move sometimes but it may be wishful thinking. Just wish I knew when to quit and tear down. really don't want to do that. maybe another month will help. Thanks again for the help.

If I pull the bleed screw can I get the atf/acetone down to the plunger??

I would suggest so, as air/fuel is released when bleeding, as per Edb picture you can see the journal to the plunger chamber, hopefully your super lube will reach the plunger

I was not able to get anything in the bleeder screw orifice so I just tapped on the lifter with my 1.5-2 oz hammer very gently and used snake oil # 3 rust bomb and after setting several hours I got it to move slightly and kept after it. The plunger started moving and the rack moved , I bleed the injector line and she LIVES again.

Just wanted to say THANKS to everyone that gave me a piece of their mine in a nice way LOL. Thanks again.

Good to hear you have it running again, now time to add a couple of pictures of it

Fantastic news Bobby! And I second Busso's "requirement" : ) plus a video would be fantastic (youtube ideally because everyone has access to that)