[s-cars] pressure tester?

David Kase dbkase at gmail.com
Wed Oct 28 13:32:22 PDT 2009

Thanks Bob 'cause she is going under the knife again tonight.  Do you know
where I can find Forgie's library?  I lost it and will want to do some
checks on the MAF and other bits tonight.


On Wed, Oct 28, 2009 at 4:24 PM, Robert Myers <bob at chips-ur-s.com> wrote:

> Big leak sounds under boost is what you might well expect if your split
> hose is staying closed until some boost hits.
> I'm kinda bumfozzled over your problem.  It's probably something very
> simple but at the moment DAMFINO what it might be.  I'll keep thinking about
> it and let those with better heads than mine come up with a good answer for
> you.  If I think of something I'll get back atcha.
> At 04:07 PM 10/28/2009, you wrote:
> Nuts.  No big power before whip-lash.  As soon as I try to give it some
> throttle she cuts out hard.  It has also been inconsistent.  Sometimes it
> will not cut out as easily as others.  I also thought I could hear a big
> leak when I could actually pull some boost without it cutting out.
> What about the TPS?
> On Wed, Oct 28, 2009 at 11:01 AM, Robert Myers <bob at chips-ur-s.com> wrote:
> I really wouldn't expect an air leak in the induction system to lead to
> overboost type symptoms.  What should happen with a big leak is difficult
> starting, poor idle, low power - all due to excessively lean mixtures.
> Whiplash cut-out is usually either overboost or rev limiter.  Neither of
> these should be happening.  There's gotta be something else going on.
> Does it seem REALLY responsive before the whiplash event?  IOW, is boost
> coming on big-time?
> At 10:52 AM 10/28/2009, you wrote:
> Thanks Robert.  Pressure Test part deux coming tonight.  I will report my
> findings.  I already have a Samco and metal cross over pipe on the way.
> Let's see what else I need.
> Do you think a 1" cut could cause major bucking at even low pressure?  The
> cut is squished together under no load and I tried to seal it with Yamabond
> - a rubbery sealant.   I got whip lash on the way to work this morning.  Boy
> that sucked...
> On Wed, Oct 28, 2009 at 10:40 AM, Robert Myers <bob at chips-ur-s.com> wrote:
> It holds fairly well.  Not TIGHT but decent.  Enough so that the setup is
> helpful.  You should be able to add pressure up to maybe 10 psig or so.  Too
> much and the clamp will blow off with a big POP! and it will surprise the
> bejesus out of you but no damage just put it back on and tighten it a bit
> more and then don't get too carried away with the air hose.  If it simply
> won't pressurize then ya gotta real leak.  These cars won't run worth s***
> with a big leak.
> At 10:33 AM 10/28/2009, you wrote:
> Thanks Bob.  This is what I did last night.  I stopped when I found the cut
> in the hose.  I will have to try again after I get a proper hose in place.
> Thanks for the details and picture.
> I ended up plugging the other end of the intake tract to as I thought air
> would just go through the cylinders with both valves open.  Does the
> throttle body actually hold the pressure?
> On Wed, Oct 28, 2009 at 8:28 AM, Robert Myers <bob at chips-ur-s.com> wrote: Dave,
> Do you have a pressure tester for your car?  It's a simple matter to make
> one.  5 or 6 inches of 3 inch diameter PVC pipe, a 3 inch pipe cap drilled
> for a tire valve plus one tire valve.  Glue cap (with valve) onto the
> section of pipe.  To use disconnect the air hose from the MAF and clamp the
> gadget in its place.  Now pressurize the intake system with shop air.
> Assuming it holds at least some pressure for a brief period you can use the
> "HISSSSSS" of escaping air to locate a small leak.  See pitcher (cain't spel
> picture).

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