Vance---A week or two, like being away on vacation, hasn't been long
enough for evaporization of fuel in the carb bowl.. (Even with only one
bowl!) There have been times when I've had to empty the bowl while
doing other work. When this is the case, I just connect clips from the
pump to a good ground and turn on the key. This fires up the pump, and
within a few seconds I hear the pump slow way down, so I know the bowl
is full. Then I remove the temporary jumper. Those that store their car
for long periods can easily do the same. OR, forego this and permanently
wire the pump directly to a known ground. OR, use an Inertia Switch,
which can have its own annoyances with false stops.
We know engines using FI systems need a pump that uses much higher
pressures.to work their injectors. I'm not sure if these have an
immediate "reserve of fuel" to draw from for start-up as we have with
carburetor bowls. If this is true, waiting for oil pressure to build
could delayed starting
Recall an earlier post about cars with automatic trannies that can
still allow their engines to keep running, even after a collision? These
need the added safety of an Inertia Switch.
Dick
From:
vance.navarrette@intel.com(Navarrette, Vance)
Dick:
It seems that using the
oil pressure switch to ground the pump might suffer from long cranking
times after the car has sat for a while. Do you find this to be the
case?
If the ground to pump
goes away when the oil pressure drops, then by definition there is no
power to the pump when you turn the key to start the car. The car would
only start by virtue of the fact that carbs will have fuel in the float
bowls. But if the car sat for say, a week, and the fuel had evaporated,
then the car will crank until there is oil pressure and power to the
fuel pump. If you are using the OEM filter, this could be many seconds.
If you run the heavier oils as some do, then the cranking time would
stretch out even longer as it takes longer to build oil pressure.
Doesn't it seem like an
inertia cutoff switch would be easier on your starter? Or is there
something I am missing? It also seems that this scheme would not work
well if your car were injected as <ahem> some *blasphemers* have seen
fit to do. The car would never start until the pressure built up enough
to kick off the fuel pump.
....So am I missing something, or do you
occasionally have long cranking times with the OP switch providing the
ground?
<grunt, scratch>
Vance
More details, if you want or need them.
<snip>
Dick
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