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Please help me diagnose! Weird power drop, possible boost leak!

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Old May 12, 2012, 10:23 AM
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Question Please help me diagnose! Weird power drop, possible boost leak!

Car facts: 2008 EDM MR
Mods: Air filter, Downpipe, Exhaust, Tune, roughly 380hp

I experience a very severe loss in power at about 1bar
pressure. The weird thing is that the boost drop doesn't
really show up on my boost gauge. Is it possible to have
a boost leak in a location where it wouldn't show on the gauge?
(gauge is connected to the low diameter regulating hoses)

Also the idle (for example ideling at a light) is sometimes weird and
drops to below 500rpm. Motor never completely died yet, though.

So say I'm accellerating in 4th gear, car get's into boost, suddenly
it just bogs down, a glance at boost gauge doesn't show a instant drop.

Alteratively, could it be the SST being messed up/broken?

I checked all the turbo hose clamps I could see without disassembly/lift,
about 70% of all clamps total.

What I deducted from this:
If the SST is COMPLETELY disengaged while standing on the brakes at a light,
it can't really be the SST since the idle is so strange. That would only
happen if the SST is somewhat engaged while standing on the break.

If it's a boost leak, it must be big enough by now to also pull outside air
at idle, not just at a certain boost level.

I just don't understand why the car behaves normal in other conditions where
the idle is sometimes very rough and at a certain boost level it just
bogs down HARD without my boost gauge showing boost dropping off.



ANY help is much appreciated!

PS: I didn't read the error codes since there is no light showing on the dash.
Is it possible for a error code to be logged without a light showing on the dash?
Old May 12, 2012, 10:34 AM
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Bad spark plugs? It's an '08 so it's about time to change them if you hadn't done so already. And plugs usually don't set off any CELs..

My 8 started doing that REALLY bad and it just needed new plugs. Although the stupid guys at a "performance" shop couldn't figure it out.
Old May 12, 2012, 10:36 AM
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If you take your foot off the gas and then floor it again does the car pull like normal?
Old May 12, 2012, 11:06 AM
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Originally Posted by ugakirk
Bad spark plugs? It's an '08 so it's about time to change them if you hadn't done so already. And plugs usually don't set off any CELs..

My 8 started doing that REALLY bad and it just needed new plugs. Although the stupid guys at a "performance" shop couldn't figure it out.
By heart I'm not sure if we changed them yet but I'm inclined to say I did about a year ago... Also: Would that cause that severe bogging down?

Originally Posted by ugakirk
If you take your foot off the gas and then floor it again does the car pull like normal?
Just bogs down again... Why? What was your thinking?



Added detail: I experienced the weird idle only once the car is warmed up... If it's cold the idle seems pretty normal. Maybe coincidence, maybe useful?

Last edited by germanracing; May 12, 2012 at 11:11 AM.
Old May 12, 2012, 03:19 PM
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Check your blinker fluid...
Old May 12, 2012, 09:40 PM
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How is your A/F ratios under WOT? I had a similar issue where I would go lean at WOT and the issue turned out to be my fuel pump relay.
Old May 12, 2012, 09:46 PM
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do a search for the fuel pump relay problem... that is your culprit my friend... swap the daytime running lamp one for the fuel pump relay... it's not kicking into high voltage.. do the swap and the boom.. fixed.. but reset your battery cuz you've been pulling timing trying to boost at 8volts of fuel pump
Old May 13, 2012, 01:21 AM
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Originally Posted by ravenjam
How is your A/F ratios under WOT? I had a similar issue where I would go lean at WOT and the issue turned out to be my fuel pump relay.
Originally Posted by feautoevo
do a search for the fuel pump relay problem... that is your culprit my friend... swap the daytime running lamp one for the fuel pump relay... it's not kicking into high voltage.. do the swap and the boom.. fixed.. but reset your battery cuz you've been pulling timing trying to boost at 8volts of fuel pump
Swapped it, no difference...

Had the window open when I tried a pull, heard a softened "clang" noise as it was loosing power... Not like metal on metal, more "rubbery" if that makes any sense...
Old May 13, 2012, 07:10 PM
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http://www.youtube.com/watch?v=Qr57M...e_gdata_player

Maybe this will help???

Hope you figure it out!
Old May 14, 2012, 10:17 AM
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Originally Posted by fastyouth1313
http://www.youtube.com/watch?v=Qr57M...e_gdata_player

Maybe this will help???

Hope you figure it out!
FYI: this FPR hose can pop of on either end (so check under your cover too). it's not a bad idea to zip tie each end down anyway.
Old May 14, 2012, 10:17 AM
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also, have you tried cleaning your MAF sensor?
Old May 14, 2012, 12:27 PM
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Thumbs up

Originally Posted by fastyouth1313
[url]
Maybe this will help???

Hope you figure it out!
You, good Sir, are both a gentleman and a scholar! Thanks so much!

I thought I checked all the vacuum hoses and turbo hoses, turns out I just didn't know about that one under the cover!

Put a brand new hose WITH zip tie on...

Cheers again, very much appreciated!
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