[V8] Engine Still Not Running Smoothly ...

urq urq at pacbell.net
Sun Nov 8 12:09:51 PST 2009

Thanks for the quick response Jason and Ingo,

Sorry that I wasn't clear in my description, the "shhhhh" sound is clearly coming from the intake manifold.  It is a pronounced and sharp sound, sounding much like my recollections of an unfiltered multi-barrel carburetor idling back in the olden days.  I don't recall hearing this sort of a sound from a PT motor before ... 

I'm pretty sure the source of the sound is the ISV.

Steve Buchholz

-----Original Message-----

As have I -- crack in the line (black hard plastic) underneath the passenger strut to mount. Hissing sound and cause of elevated idle. 

Ingo Rautenberg

-----Original Message-----
From: Jason Wilkerson

When I first bought my v8 there is a frequency valve under the passenger front fender - it had a rip in the diaphram - made a hissing sound.  Also, I've seen the hose going to the FPR rip and do the same thing.  Worth a look.

--- On Sat, 11/7/09, urq <urq at pacbell.net> wrote:

> When I got the engine back together I
> left the big cover that holds the air
> filter in place off (the air filter was installed).�
> The engine does seem to
> run more smoothly � perhaps due to the fact I had to mess
> with � of the
> spark plug wires when I pulled the distributor.� I�m
> still thinking the
> engine is a bit down on power compared to the other car �
> but perhaps this
> is due to the cams from the automatic engine � 
> As those who have pulled this cover know, the engine intake
> sounds are much
> more audible with the cover removed.� One thing I
> noticed was that I could
> hear a variable hissing at idle.� I�m thinking it is
> the ISV, and perhaps a
> sticky ISV � but it did seem to cause a bit of rough
> running.� I
> disconnected the ISV and kept the engine running by
> cracking the throttle a
> bit, no hissing.� 
> I�m going to use the carb cleaner method to see if the
> ISV is sticky, but if
> any others out there have had to deal with similar issues
> and have something
> to share I�ll appreciate hearing from you!
> Steve Buchholz

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