trouble starting in '86 5kcstq (HELP! More problems!!!)

[Pat Dooley]

Many turbo cars come with a full range(boost/vacuum) gauge.
The gauge usually taps into the intake manifold, which is after the turbo,
and it will read vacuum at idle.
A free-wheeling compressor wheel will have no effect on the air-flow plate
compared to the motor's natural vacuum.

You would only be rich under boost.  Metered air would blow out of the leak
source instead of burning in the combustion chambers.
~90 percent of the time the entire intake tract will be in vacuum, meaning a
lean condition, upstream or downstream from the compressor wheel.

If you don't believe me, rip a hole in the Michelin man hose(after turbo)
and hook up an air/fuel meter.
Guarantee it will read lean if it idles at all.


> -----Original Message-----
> From: quattro-admin at audifans.com [mailto:quattro-admin at audifans.com]On
> Behalf Of Ken Keith
> Sent: Wednesday, November 07, 2001 11:41 AM
> To: pdooley at gte.net; quattro at audifans.com
> Subject: re: trouble starting in '86 5kcstq (HELP! More problems!!!)
>
>
> Is this true when the leak is after the turbo?  Seems like the exhaust
> would be spinning the turbo, causing air to be sucked through the
> airflow meter, increasing fuel delivery, meanwhile the air leak would be
> venting the metered air out of the system.  So, it would be excessively
> rich.  This is just like using a blowoff valve in a CIS car.
>
> In an air leak that was before the turbo, between it and the
> airflow meter,
> I agree it would be lean, since air is getting sucked into the system
> without the CIS knowing about it.
>
> Isn't that correct?
>
> Ken
>
> Pat Dooley wrote:
> >
> > On the contrary, a massive air leak would lead to a lean condition.
> > Un-metered air would reach the motor without lifting the airflow plate.
> >
> > > Sounds like a massive leak in the air induction system, and the
> > > resulting rich mixture flooding the engine.  Check your hoses between
> > > the turbo and the intercooler, and the intercooler and the throttle-b>
>
>