RE: No Boost S4

[QSHIPQ@aol.com]

>I 'teed the gauge into the manifold line that feeds into the ECU. I
>started the car and figured I should read some level of vacuum at idle. I
>read 0 PSI. I reved the engine, still the gauge reads 0 PSI. I went for a
>little ride and still 0 PSI.

>So I disconnect the fittings and blew into each leg of the T to confirm
>the fittings are good, and the gauge works. Everything works. I then
>checked to make sure the manifold to ECU line wasn't kinked.

>Next I suspect that I've blown an intercooler hose. I check those and no
>problems found. 

>I'm stumped here. This is my first turbo charged car, so I am far from an
>expert. The car runs fine (albeit with less power), you can hear the turbo
>charger spool up fine, but the engine reads no boost nor vacuum. I figure
>if I had a blown turbo charger I wouldn't hear it spool up, and I should
>be a least reading engine vacuum. 

If the turbo has failed you should read no boost, but you will have normal
engine vacuum.  My assessment:  A) You have indeed NOT t'ed into the ECU line,
or B) you have a defective guage.  It is one or the other, I suspect A.  On a
mechanical boost guage, with the car off, you should read 0psi.  With the car
at idle you should read around 20in of vacuum.

For a loss of boost, ck the IC hose that is underneath the car on the drivers
side, it is about a foot long and has an accordian section on it (sounds like
you already btdt, but ck it again really carefully, I missed one once).  Pull
that hose off, and ck it thoroughly for a tear.  TAP sells a Samco silicone
hose replacement for that piece that you won't replace again in your lifetime.
Next ck the turbo bypass valve for any rips in the diaphram.  The sport q
replacement valve uses a little stiffer diapham and spring, or TAP sells an
aluminum one that is a bolt in replacement, and is serviceable.  The hose or
the valve are the two most common failures with the 20vt mods.

IF you have no boost at all, the engine puts out about 125HP, it sure doesn't
sound like this is the problem you describe.  If the car runs, you have
vacuum, that is the 'law of combustion motors'.

HTH

Scott Justusson
QSHIPQ@aol.com
'87 5ktqwRS2
'84 Urq