TBI fuel pressure regulator question

[Len Sabatine]

>  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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