TBI fuel pressure regulator question

[LWester]

Yes--if that was deadhead pressure, you've got a worn pump.

Lyndon.
----- Original Message -----
From: "Bruce" <nacelp at bright.net>
To: <gmecm at diy-efi.org>
Sent: Sunday, September 17, 2000 9:29 PM
Subject: Re: TBI fuel pressure regulator question


>
> Seems terribly low to me.
> Bruce
>
>
>
> ----- Original Message -----
> From: "Jay Vessels" <jwvess00 at home.com>
> To: <gmecm at diy-efi.org>
> Sent: Monday, September 17, 2001 9:54 PM
> Subject: Re: TBI fuel pressure regulator question
>
>
> > Hi there!
> >
> > Dad rigged a fuel pressure gauge today and powered the pump.  The gauge
> was
> > connected to the fuel filter outlet such that the fuel filter was only
> > connected to the gauge (i.e. no return path, just pressure to the
gauge).
> > Reading was 15.5 psi.  I assume this is enough for a TBI pump
deadheading
> > into a gauge.
> >
> > The return line from the TBI doesn't have any fuel flowing from it when
> the
> > pump is running, so Dad's going to tear into the TBI and make sure it's
> > okay inside.
> >
> > The real problem for me is that Dad's got the car, and his house is 90
> > miles away from mine, so we're having to work through some of this by
> phone
> > until I visit again.
> >
> > Jay Vessels
> > 1982 Chevrolet S-10 Sport, 2.8V6 TBI
> > 1994 Chevrolet Cavalier Z24 Conv., 3.1V6 MPI
> >
> >
> > At 03:45 PM 9/17/01 -0400, you wrote:
> > >
> > >>  Carefully Check the Fuel Cap , The Fuel Pickup , The Fuel Line
> > Orientation,
> > >      Check The Strainer @base of fuel pickup. A bone yard Pump may
have
> spun
> > >      one of the plastic pump rotors. Pump internal bypass may have a
> > problem.
> > >      Watch the FP relay Voltage vs Bat Voltage. Major Irregularities [
> Draw]
> > >      indicate a FP failure in progress, or a major restriction.
> > >     Double , Double Check ground connections and resistance values.
> > >     Something as silly as a small piece of debris in pump can make you
> go
> > >     bonkers. Anything that can go wrong usually will do so.
> > >     Len
> > >
> > >
> > >> >Hi there!
> > >> >
> > >> >Dad and I are currently converting my cousin's '85 Caprice 305V8
> > >> >Q-jet/700R4/federal emmissions to a TBI system from an '89 (305V8
TBi
> > >> >1228746 ECM/700R4/Federal emmissions) and have run into an
interesting
> > >> >problem.
> > >> >
> > >> >I finished modifying the '89 harness and finally got it installed
> today.
> > >> >Dad finished plumbing the fuel lines, and we decided to check for
> > leaks.  I
> > >> >jumpered across the fuel pump relay (ECM not installed yet) to run
the
> > >> >pump.  We had fuel all the way to the TBI, but almost no fuel came
> from
> > the
> > >> >return line.  Cracking open the fuel feed line at the TBI after
> removing
> > >> >power from the pump yielded a spray of fuel.  The return line during
> this
> > >> >test was simply a 3/8" steel line from the TBI emptying into a small
> jar
> > >> >(not connected to the fuel tank).  The canister vent line was
unhooked
> to
> > >> >make sure the tank was venting.
> > >> >
> > >> >It seemed odd, but we buttoned everything up and tried to start it.
> It
> > >> >would spin over fine, and acted like it wanted to start but only hit
> once
> > >> >or twice.  it would not run on its own.  Using an inductive timing
> light,
> > >> >we verified that spark was getting to the plugs (we tried a couple,
> not
> > all
> > >> >8).  Shining the timing light at the injectors shows fuel is being
> sprayed
> > >> >into the throttle bores.  We also verified that the distributor
timing
> is
> > >> >close (i.e. we don't think we're off a tooth or anything like that).
> > >> >
> > >> >Another thing I noticed, besides the lack of fuel flowing from the
> return
> > >> >line, is the fuel pump is LOUD.  I can hear it run quite loudly.  I
> can
> > >> >hear the pump in all the other cars, but they're not nearly as loud
as
> > this
> > >> >one.  It is a junkyard piece so I don't know it's history.  Dad is
> > going to
> > >> >get a fuel pressure gauge tomorrow.
> > >> >
> > >> >It acts just like it's not getting fuel, but I know the injectors
are
> > >> >firing.  Is this a case of really low fuel pressure, or is there
> perhaps a
> > >> >problem with the throttle body (i.e. pressure regulator)?
> > >> >
> > >> >Any ideas are greatly appreciated.
> > >> >Jay Vessels
> > >> >1982 Chevrolet S-10 Sport, 2.8V6 TBI
> > >> >1994 Chevrolet Cavalier Z24 Conv., 3.1V6 MPI
> > >> >
> > >> >
> > >> >
> > >> >
> > >>
> >
>
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> > >> >
> >
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