Hi Ron,
> The pre-pump you are talking about would help the bubbling a little, but
> don't think it's needed.
Think about the bubbles again. Why are they there? They are not in the
tank, right? So somewhere down the line the fuel starts vaporizing. Why
is that, and how can you prevent that? This is where the pre-pump comes
in. No pressure drop = no bubbles. No bubbles = no vapour lock.
> If you are hell bent on a pre-pump, I actually have one that would work.
It sounds interesting. I have to measure to see if it can be made to fit
the tank outlet. Also I would prefer a pump that is "open" if switched
off. This way I can only activate it when using mogas, hot and/or high,
during take off. Or I have to use an external bypass with check valve,
but for an in-tank pump this is complicated.
I will come back to this once I have made up my mind, will let you know.
> Just a quick note, both pumps ran off of a fuel pump relay, after
> between ~ 85K and ~ 125K they too would fail. What would happen is
Fun isn't it, these modern cars? My daily driver is a 1972 Mercedes 300
SEL (V8, running on propane, all options) and it just keeps going,
almost no maintenance. :-) Imagine the looks of people every time I use
it to tow the Europa back and forth to the airport. Have been
photographed a lot of times. ;-)
> Anyway if you do go to two pre-pumps (or even one) be cognizant that two
> pumps in parallel draws enough amps that over time any solder joint that
> may flow electrons to the two pumps could in fact be a failure point.
This is why I want to make the pre-pump optional and give it its own
wiring. Also, this way I can check to see before startup that it is
working, to use it to "prime" the fuel system and get confirmation on
the gauge that it is developing some pressure.
> The first time it happened to me it was a drive you crazy malady to
> figure. First time, didn't hear the pump working with a stuck car. Come
> back and it runs fine? OK replace the pump and all is well, for a week
> or two, then the same thing, get stuck, come back and all is well.
> Depending on heating and cooling the fool joint would make or break.
I had the same thing with the EFI of my car (yes, the good old Merc.
Well, after 40 years of service I can accept this).
Frans
|