[Shotimes] Engine Starting Speed

[D Potter]

190lpm? Talk about OVERKILL!!!!!!!

I am sure you meant 190lph. Now, are you saying that, because this pumps
move a lot of fuel, that we need the regulator and fuel return line, and
therefore, by simple deduction, we can lose more weight by eliminating the
regulator and return line if we use a lower flow pump?    ;P

If your pump is worn or has low voltage and is not pumping at full speed it
can take more than a few seconds to pressurize the lines to proper pressure.
You will get enough pressure for the car to drive normally, even though it
may take 5-8 seconds to pressurize the fuel rails. I currently am
experiencing this myself. My pump runs two seconds each time it initializes.
If I want instant start I have to prime the lines at least two complete
cycles, sometime three. Or, I can just turn the key and it will start after
the pump has run for at least 4 seconds. Otherwise, she runs fine.

I don't know about needing to obtain a particular rpm to start the SHO, but
I did read somewhere in the service CD that if the motor speed drops below a
certain rpm that the system will shut it down, and this would surely include
a disabling of the fuel pump. I'm sure this function is in place at all
time, so that you must exceed this same rpm to get the motor to start.


DP




----- Original Message -----
From: "SHO GOS" <shogos@earthlink.net>
To: "SHOTimes" <shotimes@autox.team.net>
Sent: Monday, December 16, 2002 3:18 AM
Subject: Re: [Shotimes] Engine Starting Speed


> The SHO like most fuel injected engines uses a pressurized fuel system. It
> only takes a couple of seconds to get the system up to pressure. The fuel
> pump puts out 190 l a min. That's a lot of gas for the size of the lines
we
> have. This is why they have a pressure regulator and a fuel return line.
The
> pressure in the lines should be a constant, that's what the regulator is
for
> and if there is more fuel and pressure in the system than is needed it is
> returned to the gas tank, still under pressure.
>
> Put a gauge on your rail and you'll see that when you turn on the key the
> system is pumped up to operating pressure. This is one reading that you
take
> when you are doing an injector leak test along with injector bleed down
rate
> and the amount of current your injector is drawing.
>
> If your pressure leaks off after shut down and then you turn the key back
on
> the system is repressurized. If the engine cranks for a longer period than
> normal then your cylinders have raw fuel in them, like a flooded engine
> condition but not as bad as fully flooded. If you do have a weak injector
> you'll notice the engine cranking longer when the engine is cold.
>
> Where is it written that the PCM shuts off the fuel pump under 120 rpms?
>
>
> ----- Original Message -----
> From: "Kevin & Cheryl Airth" <clubairth@cajunnet.com>
> To: "SHO GOS" <shogos@earthlink.net>; <shotimes@autox.team.net>
> Sent: Sunday, December 15, 2002 11:08 PM
> Subject: Re: [Shotimes] Engine Starting Speed
>
>
> > 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.
> > .
> > .
> > .
> >
> >
> > > 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.
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