[V8] Vacuum hose

[Ed Kellock]

There is a hose that is merely a vent for the transmission.  The open
end of it is usually stuck to the firewall behind the engine on the
passenger side.

There are some other vacuum hoses to check.  If you remove the airbox,
there is a smaller one (smaller than the two large breather hoses that
you have just replaced).  This smaller hose attaches to a fitting just
below and toward the passenger side of the intake opening.  It
connects to the climate control system so it goes back and to the
firewall.  There is another in that general area that goes up and over
the intake opening connecting the left and right banks.

Also in the front of the engine on the drivers side, there is another
breather hose that is tucked just under the intake plenum, connecting
that to the engine block.  I believe those rarely require attention,
but it's a hose so it's worth checking.

Your gray smoke on acceleration could be an overly rich condition
caused by the temperature sensor on the rear of the passenger side
head.  This might also cause difficult starting though too.

The high idle could be caused by the Idle Stabilization Valve which is
the black cylinder on the front of the engine, right up top in the
middle.  This can be removed fairly easily and cleaned with fuel
injection system spray cleaner.  Ordinary carburetor cleaner is
typically considerd to be too strong for the ISV.  It is possible to
activate the function of the ISV with a 9 volt battery so you can get
the cleaner in there better, but you may see improvement without that
if your's is pretty dirty.

Check the knowledge base at audifans.com for more ideas and for
write-ups of some of the information I have written above.

Ed


On 5/3/07, Bernard Larriu <bernard at larriu.com> wrote:
> Hello from France
>
> i did change the two big vacuum hoses since then i have a real bad
> MPG (grey smoke on acceleration and 1200- 1600 rpm on neutral).
> i found a small hose that come from under the gearbox (passenger
> side), burned on the exhaust pipe, but i don't find where to plug the
> upper( U form) part.
>
> Any idea?
>
> 92 V8
>
>
> Bernard Larriu
> bernard at larriu.com
>
>
>
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