Vehicle & Technical > Defender

waste gate

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rollazuki:
the only way to make it open is to increase boost levels on the intake side of the turbo to the point where boost is excessive and the 'gate' opens. This is unlikely to happen when stationary with no load on the motor.. Just check the pipes are all in good order, and  if need be, cycle the wastegate lever by hand with something like a vicegrip/molewrench to check its not siezed. Be carefull, its fairly robust, but damned expensive. If you have a boost gauge fitted, get the car in mebbe 3rd gear and nail the throttle. The boost should rise to perhaps 0.7 bar, then get no higher, as the wastegate should have opened and be dumping exhaust gas. If it keeps rising and gets over 1 bar Id say its siezed closed. If it never gets much more than 0.1-0.2 bar its siezed open.

Porny:
As stated, you only get boost under load.


--- Quote from: "rollazuki" ---increase boost levels on the intake side of the turbo to the point where boost is excessive and the 'gate' opens
--- End quote ---


Sort of....

Boost pressure is the pressure that is in the intake side of the engine.

In simple terms, the air comes through the air intake, into the turbo where is gets compressed and thus pressurises the the intercooler (and pipework) and the inlet manifold.

The actuator simply controls this pressure and when it becomes too high opens the poppet valve on the turbo to allow excess 'boost' pressure to escape.

But this will only happen under load, and not just revved.
This is because the turbo will not be spinning fast enough... if just revved, and not under load it will only have low cylinder pressures, thus the pressure coming out the exhaust ports into the turbo will be low - enough to spin the turbo, but not enough to produce 'boost' pressure.


To test the actuator, as rolazuki stated, with the engine off you should be able to use a set of mole grips to move the actuator arm to check it's not seized.
Other than that you need to connect a boost gauge, and check 'boost' pressure under load.  The best condtion for this is attack a steepish hill in third gear - getting the engine to work. Under full load, the boost will get to the highest level it can - which it won't always quite do under normal driving.

I've attached some pictures of my boost gauge on my old 90.... it is connected as per Land Rover instructions (although there are other ways).


For a 200Tdi (which I think yours is) you should get 0.8 bar (11.6 PSI) although, if you after a bit more power this can 'safely' (i.e. you 'shouldn't have any problems) increase this to 1 bar (or 14.6 PSI) - mine was set to a peak (under the condtions mentioned early) at just over 1 bar.



Ian

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