4.2 Fuel flow route - Can someone explain it

[JensenA]

Right then...as the title suggests, what route does the fuel flow take on a 4.2 with Air Con? I'm confused.

2 Pipes enter the bulkhead on the passenger side.
Pipe 1 goes to the Fuel cooler at the front of the engine, connected by a bog standard jubilee clip. It then exits the fuel cooler and goes to the Fuel pressure regulator at the back of the fuel rail.
Pipe 2 has a Banjo fitting that attaches to the driver side of the fuel rail. To me, this implies that this is a High pressure hoes and the one that supplies fuel.
In which case, what is the purpose of the pipe that goes to the fuel cooler?

[longbow]

The fuel leaves the engine via the regulator - it is essentially the check valve that generates the required back pressure in the fuel rail. It goes from here to the fuel cooler at the front of the engine, afterwhich it will be routed back to the tank. I don't have aircon because I removed it (personal preference) and I was surprised that the fuel cooler was in the return line to the tank. I thought that it was a fuel pre-cooler, but not as it turns out. I remember reading somewhere a while back that the cooler was used to stabilise the temperature of the fuel in the tank as early cars suffered from heat soak from the rear silencer up through the boot floor and into the tank. I can't say mine has been any worse without it (cooler was removed with the aircon stuff).

Edited by longbow on Tuesday 27th July 18:45

[JensenA]

longbow said:

The fuel leaves the engine via the regulator - it is essentially the check valve that generates the required back pressure in the fuel rail. It goes from here to the fuel cooler at the front of the engine, afterwhich it will be routed back to the tank. I don't have aircon because I removed it (personal preference) and I was surprised that the fuel cooler was in the return line to the tank. I thought that it was a fuel pre-cooler, but not as it turns out. I remember reading somewhere a while back that the cooler was used to stabilise the temperature of the fuel in the tank as early cars suffered from heat soak from the rear silencer up through the boot floor and into the tank. I can't say mine has been any worse without it (cooler was removed with the aircon stuff).

Edited by longbow on Tuesday 27th July 18:45

Thanks, that explains it. I too was under the impression that the Fuel cooler was used to cool the fuel before it entered the engine, hence my puzzlement.

[skidoo]

i maybe way off the mark but if hot fuel goes back to cool tank does it not produce condensation/water in fuel