[Diy_efi] Warm start problem

[Bill Washington]

Greg,
    In my case I do not know when the pump died, but when I removed it 
the copper on the commutator was completely worn away - how it had run 
that long I do not know!

Also in my case the high pressure pump was able to draw sufficient fuel 
from the tank most of the time the crunch was: hot weather + sustained 
Highway speeds (one hour +) + low fuel in the tank ..... remove any one 
of those variables and everything worked fine! ie the problem occurred 
mid afternoon, but by late afternoon when the temperature had dropped 5 
degrees the problem went away.......likewise, slow down, or fill the 
tank and the problem was not observed ....
Bill
> Today's Topics:
>
>    1. Re: Warm Start Problem (Gregg Eshelman)
>   
>
> ------------------------------------------------------------------------
>
> Subject:
> Re: [Diy_efi] Warm Start Problem
> From:
> Gregg Eshelman <g_alan_e at yahoo.com>
> Date:
> Sun, 15 Jul 2007 17:13:45 -0700 (PDT)
> To:
> diy_efi at diy-efi.org
>
> To:
> diy_efi at diy-efi.org
>
>
> --- Bill Washington <bill.washington at nec.com.au>
> wrote:
>
>   
>> Mike,
>>     To me this sounds reminiscent of a heat
>> soak/fuel vaporisation problem.
>> I would look at fuel distribution manifold temp, and
>> also your low and 
>> high pressure pumps - if your high volume/low
>> pressure pump (often in 
>> tank) has died the high pressure pump may not be
>> able to supply enough 
>> fuel flow to clear a vapour lock in the manifold.
>>     
>
> Most vehicles with EFI use the fuel to cool the
> in-tank pump. Running around a lot with 1/4 tank or
> less can lead to an overheated pump. Some cars have
> an open-cell foam sleeve around the pump to wick fuel
> up for cooling when the level is low but many just
> use something like a corrugated "rubber" ring to
> hold a small amount around the pump. It vaporises
> then the pump gets hot until you make a hard enough
> turn to slosh fuel over the pump.
>
> It's expensive these days to keep the tank at least
> half full, but it'll save the annoyance of having
> your pump quit in the middle of nowhere- or the
> middle of a busy intersection downtown.
>
> P.S. What's weird is so many about-to-quit pumps
> will conk out right after you fill the tank completely
> full... dunno why but that's when every one of the
> EFI pumps I've had fail has chosen to fail. That's
> also happened to the majority of the people I know
> who've had a pump quit. Maximizes the annoyance factor
> of Murphy's Law!
>
>   
>