[Shotimes] Engine Starting Speed

[Kevin & Cheryl Airth]

Yes exactly but it does NOT run until they are pressurized it is only time
based and that may be causing the problems. You can prove it by cycling the
key. The pump will run for exactly the same amount of time every switch of
the key, regardless of the pressure in the fuel rail.  As you said even when
the engine stops running there is still some pressure left in the fuel rail
but not enough to run the engine. Think about it, If your pressure leaks off
after shutdown. Then you start the engine from a very low pressure
situation, it might run rough or even stall until the pump is running
continuously. Fuel pumps usually fade out and do not give a nice clean
failure which would feed this even more.
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> My fuel pump runs longer than 1 second when I turn on my key, more like 3
> and it does pressurize the fuel rails. Disconnect your fuel pump, start
your
> engine and let it burn all of the fuel left in your rail. I'm willing to
bet
> that there's still pressure and fuel left in your rails. To test this for
> yourself, smack that fuel pump cut off switch on your trunk, start your
> engine and run it until the engine dies. Now pop your hood, remove the cap
> from the shrader valve on your fuel rail and press in the valve and see if
> you don't get sprayed by gas.
>
> I've cleaned several SHO fuel rails and injectors and every time I hook up
> the hose to the fuel rail shrader valve I have a shop towel on the other
end
> of the hose so the gas doesn't go all over the engine. After every thing
is
> hooked up I turn on the key to allow the pump to run so I can dump that
> pressure into the cleaner can just in case the can's internal pressure is
> low.
>
>
> > This is common to all EEC-IV vehicles. If the rpm is below 120 rpm the
PCM
> > will not let the fuel pump run. So that is the lower limit, if the
starter
> > can not spin the engine at least 120 rpm it will never start. Remember
> that
> > when you turn the key on it does NOT pressure the fuel system to 39 PSI.
> It
> > ONLY runs the fuel pump a fixed length of time. Usually 1 second. That's
> why
> > when your fuel pump is weak you need to cycle the key several times.
With
> > only running 1 sec. it might take 5-6 cycles to build enough pressure
for
> > "instant" start.