Josh Hart wrote:

> Anyway, I got a 1992 Gli pretty recently.  I got a
> Carfax report for it and found out it was a California
> model which means it has a damn EGR valve.  I once saw
> a blockoff kit to get rid of this on Ebay, but does
> anyone know if that would be safe?

It's perfectly safe.  However, removing the EGR system won't do much, if
anything, to improve performance.  On the CA Motronic cars, it consists of
the EGR valve itself, which is just a vacuum controlled valve attached to
the intake manifold plenum, and a tube that runs from the exhaust manifold
to the valve.  The control circuit consists of an intake manifold
temperature sensor, which reports to the ECU, a vacuum source consisting of
the vacuum amplifier, which feeds off intake manifold vacuum near the
throttle body and the brake booster vacuum source near the check valve.  The
output of the amplifier goes to a thermal vacuum switch on the coolant
flange on the head, and the output of the switch which goes to activate the
EGR valve.  When the engine reaches a certain temperature, the thermal
vacuum switch opens allowing vacuum through to the EGR valve, causing it to
open.  This allows a small amount of exhaust gas to enter the intake
manifold, which displaces a portion of the intake charge.  This causes a
slight leaning effect, reducing combustion chamber temps, which reduces
emissions.  The EGR system only operates during part throttle situations.

> I thought the vacuum line from the EGR valve went to the brake
> booster or something?  Basically, I just need some info on this procedure from
> someone who knows about it.

See above.  To disable the EGR system, you need to block off the intake
manifold port, plug the exhaust manifold "bung", and put vacuum caps on the
hose barbs at the throttle body and brake booster line located at the
driver's side rear of the intake manifold.  You can just leave everything
else in place, just securing the disconnected vacuum lines so they don't get
caught up in anything hot or moving.  This makes it very easy to reconnect
everything if/when you need to pass smog.  I just went through this whole
deal with my '92.  I have a 50mm intake manifold, which doesn't have the
port for the EGR valve, or the threaded boss for the temperature sensor.
The missing EGR was the only thing keeping me from passing smog, so I was
preparing to pull the upper half of the 50mm intake, and put the stock 42mm
half on so I could hook up the EGR valve.  I got lucky and was able to get
it smogged without actually having to do that.

--Holland
[email protected]
San Jose, CA


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