[Gmecm] 93 CHEVY g20 VAN

[Phillip Kuhn]

Well, I just consulted SI and it appears I was
completely wrong about the GM returnless system. In
fact, they almost appear the same as a regular system.
I must have been hitting the crack pipe hard when they
came out with that because I could swear that is what
I read. Anyhow I would like to argue the vaccum
reference as I found this piece of info in the service
manual regarding fuel pressure regulators:

Chevy pickup 2000 5.7 liter
The fuel pressure regulator (1) is a
diaphragm-operated cartridge type relief valve with
the fuel pump pressure on one side and the regulator
spring pressure and intake manifold vacuum on the
other side. A retainer clip (2) holds the fuel
pressure regulator in the fuel meter body assembly.
The fuel pressure regulator maintains a constant
pressure differential across the injectors at all
times. The pressure regulator compensates for engine
load by increasing the fuel pressure as engine vacuum
drops.

Cadillac Deville 2000 4.6 liter
The fuel pressure regulator is a diaphragm-operated
relief valve with fuel pump pressure on one side, and
regulator spring pressure and intake manifold vacuum
on the other side. The function of the regulator is to
maintain a constant 350 kPa fuel pressure across the
director spray plate under all operating conditions.
The pressure regulator compensates for engine load by
increasing fuel pressure as engine intake manifold
vacuum drops. The pressure regulator is mounted on the
fuel rail.

You will find a description like that for almost any
vehicle you input into the system. Anyhow, this
bickering is getting us nowhere and I am still curious
to see what is wrong with this guy's van. I will say
again that I haven't worked on a TBI vehicle in quite
some time and I wouldn't argue the presence of a
vaccum source on the fuel pressure regulator any
further. However, the regulator on thise is mounted on
the throttle body and if it were leaking it would
still get sucked down into the manifold creating a
rich condition.


		
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