new vaux engines, no fuel return pipe?

[rc]

so, newer fuel systems? no return?

how does the feed only fuel system on the newer vauxhalls work?

what we know... older vauxhalls have pump in/at the tank, fuel feed forward to the rail, keeps pumping untill the fuel pressure in the rail exceeds the fpr setting, and the rail overflows excess back down the return to the tank.

so some newer engines only seem to have a feed? does the pump just have a pressure regulator built into it tank end? can the pump only pump so much pressure?

reason for question is i want to fit a engine with a feed and return (c20xe) into a vaux which only has a feed.....

[Olsrey]

On the Vectra 1.8 my lass had the regulator was under the tank lid.

[debeerd]

The new cars pulsate the fuel pump to keep the preassure up.
I've seen it on the new toyota's Run-x and corolla's also, weird though.

[Gordo]

So how do they handle any air that enters the lines?

[debeerd]

Hey Gordo, I don't know hey.
I've tried to figure out what they have done but not sure.

On the run-x you can hear the pump pulsing while idling.
Can't think it works well, they run crap also, no power... hehehe

[debeerd]

My best guess would be like Olsrey said.
Short closed loop system in the tank with a regulator, and then the fuel rail that extends to the engine.

But like you say, air in the system would cause chaos !

[rc]

so for the vaux systems its like this, excuse the pic im at work and only have my phone to hand

top one old system, bottom one new system?

[Gary_808]

Yup, bottom one seems to be the common way of doing it these days.
And think some have a version of a check valve sorted where the feed joins the circuit to stop the fuel draining back and air getting into the single feed pipe.

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[rc]

so in theory if both systems run the same fuel pressure, i can run a c20xe on the later setup and just block up the return at the rail?

[Gary_808]

Yup,
Though it's a common thing to do on the saxo's when converting vtr-vts as vtr runs this setup, and vts runs conventional setup,

But have heard of people having running problems that were solved by running a return as standard on vts's,
Which doesn't make much sense as it shouldn't make any difference.

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[rc]

hmmmmm i see so it should work but doesnt

[Gary_808]

Yeah it's a random one, some people say it's down to vapour locks etc, and some people it runs fine so they never change it.
I'd say it's worth a try to see if it's a goer before running a new line.

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