[urq] stumbling under boost

[Gary Brown]

I found a possible culprit-
the small PCV hose that is situated below the vacuum
"T" was loose. Removed it and plugged it with my thumb
while I pumped in about 30lbs of air. (I disconnected
the ECU hose and plugged that fitting).
When I let my thumb off the PCV hose fitting, there
was a large "whoosh" of air escaping. No leaks in that
part of the intake system. 
Hooked everything back up, and it's still doing it.

Other ideas? Could it be ignition or pre-turbo vacuum
leak related?

Gary



--- DGraber460 at aol.com wrote:

>  
> In a message dated 6/6/2008 8:03:35 P.M. Mountain
> Daylight Time,  
> a.sigal at bluewin.ch writes:
> 
> My 85  urq runs great, except it has developed a
> nasty
> >stumble at full  throttle and full boost.
> >
> >Can't find a vacuum leak and duty  cycle readings
> seem
> >to be correct.
> 
> 
> 
> Sounds like classic boost leak. Turbo over-boosts
> due to lack of  resistance, 
> and ECU shuts off the fuel pump.
> If you don't have one make a pressure tester out of
> ABS pipe and a cap  glued 
> together and clamped into the turbo intake. Drill,
> tap, and install an air  
> fitting into this "plug". With this you can
> pressurize the system and with a  
> stethescope check for pressure leaks. Careful not to
> pressurize more than ~  
> 10-12 psi or you risk blowing your pressure
> transducer in the ICU. To be ultra  
> safe, isolate the ICU "just in case".
> Bet you a beer you find a leak (or 2). Even small
> leaks that vacuum  will not 
> betray will be quite obvious.
> Come out in August and I'll either collect or pay
> up!
>  
> Dennis
> Denver
> 
> 
> 
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>