Fuel leak - Modulating Piston Displacement Sensor

TDI injection pump fuel leak-
My 2002 Jetta TDI has developed a small but annoying fuel leak where the Modulating Piston Displacement Sensor mounts the the injection pump. Can someone tell me how easy the fix is? Where do I find the special socket (3 point) required to remove the sensor? Where do I find the "O" rings or gasket, once I have it off (the local VW dealership pieces department does not even list a kit)? What do I need to be careful to watch out for?

www.metalnerd.com - triangle tool
www.dieselgeek.com - seal kit; I think the kit includes the modulating displacement seal.

Tony

Thanks TonyJetta, found the tool to remove the anti-tamper bolt. Now it is time to tamper. I have a message into dieselgeek asking them if the head seal kit covers the sensor on the side. Do you know of a schematic that will show me what I will see remove (tamper with) the sensor?

There's a thread at the top of TDI101...Injection Pump!

Tony

Thanks Tony, That was very good piece about the injection pump but did not cover information about this sensor. I still need to know what I will find when I remove this sensor. Still looking.

Also search for "QA" or Quantity Adjuster.

It's position is critical. You can scribe lines to locate it but you really need access to VCDS to verify/adjust the position of the QA and the attendant IQ when you install it.

Also read up on "hammer mod" which is the manual adjustment of the QA to get the IQ in range.

Kilo Lima Xray Delta.
I will study on that, thanks for the info.

Mike

Based on this info posted by SPINDR, this sensor simply mounts to the side of the injection pump and uses hall effect to to do its job.

But still does not answer the question of what kind of seal I will encounter when I remove it. Any help???

(SPINDR) "The Modulating Piston Displacement Sensor (G149) supplies information regarding the current position of the quantity adjuster in the injection pump to the control module. The control module calculates the quantity of fuel to be injected from this information. Function An alternating magnetic field is produced in a specially shaped iron core as a result of an alternating voltage. A metal positioner attached to the eccentric shaft moves along the iron core, influences this magnetic field. The change of the magnetic field is electronically analyzed in the control module and serves asa ameasure for the position of the quantity adjuster. Substitute Function If the control module does not receive a signal from the modulating piston displacement sensor, the engine is switched off for safety reasons. The new contactless sensor offers the following benefits: (a) freedom from wear (b) High reliability against interference (c) very low-influence of temperature fluctuations."

I haven't opened mine up yet but looking at pics I've seen it aint that simple.




In this pic the displacement sensor is the rotating arm to the right. The flat thingy on the side of the pump is simply a pass through for the wires. The wires bend up on the inside and are clamped to the board by that black cover to the left held with the two nuts. I have the seal kit from Dieselgeek but it has no rectangular seal that would obviously fit that. It might use one of the o-rings but I don't know.

That was also my thought about the seal kit, no perimeter gasket, could be an O ring. Still searching for that definitive graphic that shows that sensor application.

I discovered a few minutes ago that the special tool, the triangle tool for the anti-tamper bolt on the pump cover is to large to fit the bolt on the side. So I am back to the drawing board.

If you have a Dremel you could mod the right size six point socket. If not you could do what a lot of guys, myself included do for the larger bolt. Tap a cheap socket onto the bolt. It'll deform enough to work.

That is a good idea. I can just replace that bolt with a allen head or torx. Thanks