FP: Before or after gas?

[DAC17]

Sorry for the simple nooby Q; couldn't find the answer in a search. Do I add the FP first, and then fill with gas, or gas and then FP?

Thanks.

 

[dkcase]

I do it after.
It would be better to do it first, at the gas station, for the best mixing.
But I don't carry it with me. When I get home, I add it... or when my wife or daughter says, "Oh. I got gas today." I go down and add it.
I think it mixes quite readily and there is no problem.

 

[eljefino]

Depsite my best efforts at funneling I get maybe 1 cc of leftover FP outside the unleaded restrictor and flap, but inside what will be the sealed portion of the gas cap. Am concerned that this could attract more dust that will later be ingested. Should I be? Am thinking of adding before fuel so I could use a gas "chaser".

 

[XS650]

quote:

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Originally posted by eljefino:
Depsite my best efforts at funneling I get maybe 1 cc of leftover FP outside the unleaded restrictor and flap, but inside what will be the sealed portion of the gas cap. Am concerned that this could attract more dust that will later be ingested. Should I be?

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Don't think so. If it's sealed, no dust. Your next refuel can rinse it off.

 

[Ken2]

Fuel injection systems recirculate unneeded fuel back to the tank, so the circulation in the tank will soon blend in the additive added on top.


Ken

 

[Shaman]

quote:

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Originally posted by Ken2:
Fuel injection systems recirculate unneeded fuel back to the tank, so the circulation in the tank will soon blend in the additive added on top.


Ken

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Although i am not disagreeing with you, i am clarifying that newer fuel injection systems have changed over to returnless systems that do not return unused fuel, such as the 99 and up mustangs, and the 01 and up Elantras, off the top of my head

 

[GT Mike]

They still circulate the fuel, but it's within the tank. My '94 Dakota was one of the first vehicles I've ever seen with returnless fuel injection (and no external fuel filter!). The fuel pressure regulator was inside the tank, integral into the pump assembly itself, and any residual pressure would simply bleed off back into the surrounding fuel in the tank rather than making the trip all the way up to the fuel rail and back again. Supposedly it cuts down on evaporative emissions this way.

 

[CONMCK]

I add the additive first, than use the gas fill up as an opportunity to see that any left behind in the filler tube ends up in the tank, and that all of it gets mixed in .