 Pump-injector 2
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Let's leave aside the diagnosis that leads to replacing the pump-injector elements for now. There are many reasons for this, but a misdiagnosis is also likely here. For example, it was already
mentioned that the wiring harness is in the oil. Since you're replacing it at the same time, you can also try to see if the problems that have occurred can be resolved by replacing it alone.
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Whether and how, for example, compression should be measured, which would involve relatively risky removal of the glow plugs, or whether, for example, the starter current should be
observed over the crucial strokes of the four cylinders, it would be good to know in any case whether the internal engine is still reasonably intact.
Modern diesel engines also have so many additional components that can impede their proper operation, such as the air mass meter, the particulate filter, and the exhaust gas recirculation
system. You shouldn't rely solely on the error message from the error log, especially since this is difficult for the control unit in the case of a defect in the pump elements.
So, assuming the elements on a PD-TDI need to be changed, similarities to working on common rail injectors are not excluded. However, before removing the valve cover gasket, the timing
belt gasket must also be removed. Don't worry, the entire camshaft drive remains untouched. Only the roller rocker arms, or rather both of their shafts, need to be removed.
The prerequisite is that these are not under tension, so first turn the crankshaft so that the two cams of the rocker arms on one shaft are essentially pointing downwards. Then loosen the
screws for the two PD elements and, if necessary, prepare them for removal possibly using a special tool. The older the engine, the more mass the hammer needs. But with patience . . .
kfz-tech.de/PDM47
Reconditioned and tested PD elements are available for about the same price as CR injectors. We've had good experiences with the latter, always from the same, reputable company. And the
price difference compared to new ones is a compelling argument. But please clean the shaft and especially the lower sealing surface meticulously before inserting the new one.
Installation is more complicated than with the CR. Not only does the vertical position to the cylinder head need to be checked and maintained while tightening the screws, but the adjusting
screw on the installed rocker arm must be fully screwed in with the rocker arm in its lowest position, unscrewed a certain amount, and then locked.
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Of course, you have to prevent the cam from pressing while the pump piston is already at its lowest point. Otherwise, the same rules apply as with CR: retighten all bolts with an unusually low
torque, and then add a certain amount of torque. The rest is easy: put the valve cover back on with a new gasket and timing belt cover.
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Here's the explanation for checking the perpendicularity again. When disassembling the elements, you'll notice that they're only pressed onto their seal at the very bottom on one side. If the
perpendicularity isn't checked after tightening with torque, the seals in the shaft could become partially ineffective. The video above explains this, and the company offers a solution for even
pressure.
kfz-tech.de/YDM38
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