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R.I.P.
Join Date: Aug 2009
Location: Nicholson, Ga
Posts: 2,160
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"Fluttering" mechanical boost gauge
my factory boost gauge doesn't work so i installed a mechanical gauge. Under WOT it flutters pretty wildly between 11-13psi. If I accelerate slowly and gradually build some boost it is nice and steady till i foor it. So at part throttle making 6-7psi it's steady, but at full boost it's fluttering like a scared cat. Does this sound like a bad wastegate or maybe a boost leak (aka: o-ring problem)? I have had the intercooler off several times and the o-rings appear ok. I don't hear any hissing sounds under boost indicating a vacuum/boost leak either.
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09-05-2009, 12:50 PM
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Registered
Join Date: Jul 2006
Location: S. Florida
Posts: 7,249
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Sounds like a manual or electronic boost valve thats not working right or is chattering could do that.. if there's one installed.
might be a leaking injector block? The origonal bakelite ones eventually crack and leak. |
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09-05-2009, 01:25 PM
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R.I.P.
Join Date: Aug 2009
Location: Nicholson, Ga
Posts: 2,160
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no boost controller on the car. It's supposed to have a 1 bar spring in the gate but it nevers makes over 13psi, in fact i think it only hits 13psi on the gauge do to the flutter
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09-05-2009, 01:38 PM
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Registered
Join Date: Jul 2008
Location: Central Washington State
Posts: 4,396
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Outside of the gauge fluctuation, does she run nice and smooth...no misfiring/hessitation etc.? No other symptoms other than the gauge doing the funky chicken?
__________________
Mark H. 1987 930, GP White, Wevo shifter, Borla exhaust, B&B intercooler, stock 3LDZ. |
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09-05-2009, 04:48 PM
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Registered
Join Date: Oct 2003
Location: Mount Pleasant, South Carolina
Posts: 14,166
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What's it tied into?
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09-05-2009, 05:16 PM
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R.I.P.
Join Date: Aug 2009
Location: Nicholson, Ga
Posts: 2,160
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the car runs pretty smooth at WOT, although it seems to feel alittle soft till it hits 5000rpm at which time it feels like it makes another 30-40hp. The one brief time i had my wide band on it the car would go full rich (10.1) when i floored it but i didn't watch it all the way to redline. So maybe it's running to rich causing the boost to flutter. I didn't see if the boost gauge calmed down once the engine was over 5000rpm as i was then concentrating on the tach and road. i need another set of eyes, or maybe a dyno appointment. There's only 2 of them on my street
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09-05-2009, 07:45 PM
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R.I.P.
Join Date: Aug 2009
Location: Nicholson, Ga
Posts: 2,160
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oh, the boost gauge is sourced right at the intake manifold.
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09-05-2009, 07:46 PM
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Registered
Join Date: Jun 2001
Location: Sweden
Posts: 5,911
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Quote:
__________________
Thank you for your time, |
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09-06-2009, 01:48 AM
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