Love This

[Ward Spoonemore]

I think you should check the temp of your fuel after about 30 minutes
running it should be 20- 30 deg less than the coolant temp, remember most of
the fuel is being returned (hot) to the tank at normal driving, The major
problem is keep the pump from running dry and tearing up the pump.

The "no return" systems came into favor as a result of more restrictive
rules on evap system's. If the fuel isn't returned to the tank the vapor
pressure is much reduced because the fuel is no at ambient temp, (except for
bone head door stop Camaros that have the tank in top of the muffler).


Ward


-----Original Message-----
From: owner-diy_efi at efi332.eng.ohio-state.edu
[mailto:owner-diy_efi at efi332.eng.ohio-state.edu]On Behalf Of Greg
Hermann
Sent: Sunday, January 31, 1999 8:22 AM
To: diy_efi at efi332.eng.ohio-state.edu
Subject: RE: Love This


>> >I know Toyota uses the system in the 1ZZ-FE and claims lower evap
>> >emissions as the reason, FWIW. Less vapor lock?

Keeping the fuel in the tank cooler keeps its vapor pressure down, and
helps reduce evap emissions. Yes, keeping the tank cooler also provides
more net positive suction head (NPSH) to an in line fuel pump, but it does
nothing to help with keeping fuel vapor out of the fuel rails during
hard/hot running or after a hot soak.

With no bypass fuel flow, this second problem WILL be worse.

Greg
>>
>> DO NOT let mfgr BS about less evap emissions get confused with getting
the
>> vapor bubbles out of the fuel rails!!!
>>
>The evap. test has been increased from 1 hr to 3 days so is more
>difficult to past.  Does any one know where i can get a low
>permeation fuel neck hose?
>alex