--Turbo Problems Again--

Hi lads, im beginning to think my engine is just cursed :doh: Td5 2002, decat, egr removal.

So the problem is the turbo is only kicking in about halfways through the revs,
its acting like as if the wastegate is a bit stiff and the actuator needs to build up pressure before it loosens and pushes forewards.

But ive checked that, and its loose, so im ruling that out, i do however want to know how to open the wastegate housing to lube it up if anyone knows??

anyway, ive attempted everything i can think of, replaced glow plugs (because they needed to be done anyway), replaced MAF, checked for split/delaminated hoses, checked actuator hoses and actuator.

any thoughts lads??

Just to recap, it pressurises to about 6 or 7 psi, stays there untill the latter half of the revs (in all gears) where is surges foreward to about 17psi, and then gradually reaches 20psi.

thanks

The actuator only opens the wastegate to dump excess pressure. Without the actuator connected the turbo would keep boosting until your ECU went into limp mode or you blew the intercooler pipes up like balloons.

It sounds to me like you may have a partially open wastegate (not fully closing at rest) which does not allow the turbo to build pressure above 7psi until you get to higher revs at which point the pressure builds until the actuator progressively opens the wastegate as it should at max boost. I'd try taking off the actuator and operating the wastegate by hand (it should be quite loose) making sure it moves freely in both directions. You should be able to feel it close against its seat inside the turbo wastegate housing. You then need to make sure the actuator is moving in and out smoothly (you will need pliers to move it against the strong internal spring) along its full travel. It should not catch at any point especially when it moves in towards the actuator body. Dont be shy, so long as you dont twist the actuator rod you will not damage the diaphragm. If you dont want to use pliers then you can use a bicycle pump connected to the small tube but its not so easy to "feel" any restrictions in its movement.

You can not get the wastegate housing apart to get at the wastegate butterfly bearings and in any case any lube would burn off once the turbo gets hot. You can grease the actuator rod linkages and squirt a few drops of engine oil into the actuator vacuum port to keep the internals lubed.

Possibly a blocked vacuum line to the wastegate actuator? Or just get an electronics boost controller