not seeing boost....help

1_Stealth_Z

So heres the story...Sunday I left for a trip (4 days) and the car was driving fine boost and all. I get back Wednesday night and the car wont go into boost...I can hear the wastegate let off some pressure for a brief moment under acceleration but then I get no boost....then when I let out of the throttle I can hear the wastegate sputter again. Im not the most technically inclined person when it comes to workin on my car....I know I know before I get blasted about how I should know more about it could you please offer some sound advice or opinions before I take it in to shop and have to pay a few hundred bucks for something simple. Thanks for the help in advance.

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1_Stealth_Z

oh and my boost gauge is only reading about 9 lbs of vacuum when I usually reads 20 when I let off the throttle and then while at WOT it literally doesn't make it past the 0 mark

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elperuano

Hopefully just blew off a coupler. Check those first.

1_Stealth_Z

I found a lift so im about to head over and take a look at the underside....

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SouthArk370Z

Sounds like you have a loose hose.

I've never seen manifold vacuum measured in pounds (a perfect vacuum is -14.7 psig, so your 20 doesn't seem right). Most common units I've seen are inches of Mercury ("Hg). Probably shifted to metric nowadays.

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1_Stealth_Z

my bad yea its in Hg....im slightly hung over

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phunk

I agree with the post above about probably a blown off hose coupler. Check all the couplers and clamps from the turbo to the intercooler to the throttle bodies. This would prevent building boost and prevent the wastegate from opening, since it only opens when it sees boost.

This however would not explain your low vacuum readings. Maybe you developed a tear/split in the vacuum line for the wastegate and boost gauge... but this would be a whole different thing. The wastegate wouldn't open and you would be overboosting like crazy and probably already be stuck on the side of the road with a puddle of oil and a bucket of strange metal parts on the street.

I'm going to stick with a blown off coupler for now until there is new information

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1_Stealth_Z

I don't get the lift until one so I will post new info as I find it

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SouthArk370Z

Since the car seems to be otherwise running more-or-less normally, I suspect the the piping to the manifold pressure sensor, or the sensor itself, is bad. Check for tubing and hoses going to the sensor that are loose, broken, cut, plugged, &c. While you're in there, do a visual check for any other parts that may have failed.

This may not be the problem or it may not be the only problem. Just something that should be easy to check.

Edit: And it will give you something to do while waiting for someone that knows more about FI than I do.

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1_Stealth_Z

Thanks for the input!

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