good bad boost fault

mrt72

mrt72

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evening folks,
been have a few problems as lately with the evo hitting the limiter when its booted and noticed yesterday that its started boosting to 1.4-1.5 bar instead of its usual standard 0.9.
any ideas guys? last car i had this trouble with was a golf gti and it blew the turbo shortly after.
i've not changed anything on the car to make it do this, its good cos of the extra boost but we all know its not good on a 4 engine.
 
RsvRob

RsvRob

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Evo 4 as in the pic?

That will be your actuator f*cked if its still the std one fitted without the hat :)

Don't drive on boost while its knackered as you'll over boost and blow the engine. Chase up a new or used evo 8, 9 actuator with a hat on it
 
mrt72

mrt72

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nice one rob cheers.
that was my diagnosis too, but my lad said no you'd get no boost.
and he's the mechanic lol, daddy always knows best lol
 
fq-craigus

fq-craigus

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just in case too check the pipework just to make sure a hose hasnt come off the actuator or off the turbo that would cause it to over boost too, just a tought
 
sponners

sponners

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as Rob said, prolly the actuator seized and not opening wastegate
 
RsvRob

RsvRob

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nice one rob cheers.
that was my diagnosis too, but my lad said no you'd get no boost.
and he's the mechanic lol, daddy always knows best lol

:D Yoda knows best

just in case too check the pipework just to make sure a hose hasnt come off the actuator or off the turbo that would cause it to over boost too, just a tought

Keep your nose out young padawin Yoda is working here :awesome:
 
mrt72

mrt72

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just had a quick look and all pipework is fine and the actuator is really easy to work.
so i take it the diaphram will have gone in it preventing from working.
 
RsvRob

RsvRob

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Disconnect the pipe to turbo. Leave connected to the actuator and blow into it. You will not be able to blow through if the actuator diphram is working. If its easy to blow through then its f*cked
 
B6lee

B6lee

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nice one rob cheers.
that was my diagnosis too, but my lad said no you'd get no boost.
and he's the mechanic lol, daddy always knows best lol

just had a quick look and all pipework is fine and the actuator is really easy to work.
so i take it the diaphram will have gone in it preventing from working.


if the diaphragm has split then youll get no boost but if the actuator has seized then it will no open the wastegate which as a result the car will over boost. this is a common fault on early evos so as rob said get one for a later evo as they have the hat fitted which stops the shaft getting wet and rusting
 
sponners

sponners

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does as Rob said and see if you can blow into the actuator, if you can then the diaphragm is split (common fault) and will cause overboost.
 
M

Motointrest

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you want a evo8 one not a 9 one. the 9 one is a slightly different shape due to the slightly changed turbo design. I've not tried fitting one though so can't actually say it wont go on.
 
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