Not making any boost - what to check

Hi everyone

 

I did a quick search and found quite a few threads on turbo failures and the like, but nothing that sounds like the issue I am experiencing exactly.

 

so I have a bone stock standard like it came from the factory AUDM GT-B (I'm from South Africa BTW) with just under 90k KM on (55k miles). It has a vf46 on it for reference.

 

So it's been losing power over the last month, with no noises or codes or cel or anything. after a bit of scratching around, I noticed that it is not boosting as it should, only making 0.1bar in intelligent, and peaking to 0.4-0.5 on S#. Whereas it should be 0.3 & 0.9 respectively.

 

now I have checked for obvious boost leaks on the intake side, and checked that the wastegate actuator has free movement. Also checked that the vacuum pipe between the turbo and actuator is still fine, which it is.

 

I had it past the dealer, but they booked another day to check it out properly, and I would like to do my homework before hand, as I don't want them to replace stuff randomly "until it works" as parts prices here is eye wateringly expensive.

 

Any other items that I can check? I also have a cheap elm cable which I can do romraider pulls with if that helps. With that in mind though, checked Iam as well, it's on 1 so it's happy not so ?

 

Thanks all

 

Tapatalk: HTC OneX

How's the vacuum?

How's the vacuum?

 

With the throttle closed and decelerating, -0.6 to -0.75 ish.

 

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Your sure you don't have a big boost leak ?

 

Is the tmic tight and not blown out under it where you can't see ?

 

Did you do a boost leak test ?

Hey there, nope did not do a boost leak test.

 

I did read something about that somewhere here, that's when you seal off the entire intake and pressurise it with air and listen for leaks?

 

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With the throttle closed and decelerating, -0.6 to -0.75 ish.

 

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Is that normal? Don't know your engine specifically.

When I had normal vacuum and about .5 bar boost (this is on an EJ257 though), engine was in safe mode because the knock sensor had failed. This did not set off any CELs.

See if it is detecting too much knock.

Thanks for the replies guys, appreciate the input.

 

I have given the dealer as much info as I could based on some checks with torque app on my phone and the like, as I could not check all the items mentioned here due to work constraints.

 

Will let you guys know what they find.

 

cheers

 

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Check the blue vacuum t behind the intake manifold. I've blown mine off a couple times and the car makes no boost and runs rather poorly. Its not a barbed fitting which makes it easy for the line to pop off.

sounds like TB hose.

Hey guys.

 

So it would seem I inadvertently may have caused the issue. With the known ring-land issues with the EJ255&257's I have been using NF octane booster in every tank, and this has fouled the plugs, lambda & o2 sensors and partially blocked the cat. We only get 95RON fuel in SA, which I think is about 91MON as per the standard you guys use in the 'States.

 

so we going to replace the sensors and decat the dp, and shove a mini cat infront of the o2 sensor.

 

will update once done.

 

cheers!

 

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