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difference between fuel pump assy gst gsx

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lars y

15+ Year Contributor
141
1
Oct 11, 2007
Halden, Europe
Hi,
I want to buy a new fuel pump assy, but everywhere i look i can only find the '2WD' ones (or the 2.4L w\o turbo)

I`ve looked at mitsubishiparts, jnztuning, parts.com, thedsmgraveyard and trademotion.

I`m assuming the '2WD Turbo' version of the assy is for the GST, so am i able to use this one in my 2G GSX?

Thanks
 
The AWD tank has another assembly on the other side (considering the hump in the tank for the driveshaft) which makes the AWD assembly have extra hose and wire ports/plugs to connect both assemblies.
 
So i wont be able to use the '2WD' assy in my gsx?

Whats on the other side?

dsmvenge:
I need the top lid, mines very rusty and i`m going to only be using an external fuel pump, so i want a new 'top part' i can weld AN bungs at the top and a pickup on the underside.

Thanks
 
Last edited:
So i wont be able to use the '2WD' assy in my gsx?

Whats on the other side?

dsmvenge:
I need the top lid, mines very rusty and i`m going to only be using an external fuel pump, so i want a new 'top part' i can weld AN bungs at the top and a pickup on the underside.

Thanks

No, unless you can modify it to work. It has two pickups. The arch separates the fuel in the tank. It can only pickup fuel from one side, (why with AWD you need two pickups)
 
Basically the system uses a saddle style tank with two areas of volume and a siphon hose to connect them. So there is one main output from the in tank pump that goes to the fuel rail, one return from the rail, and one return/siphon from the drivers side of the saddle tank. The siphon side works based off of the pressure of returning fuel, if there is high pressure from the rail (low load, regulator bypassing lots of fuel) the majority of the incoming is from that. When you get under higher loads, the amount of fuel bypassed by the regulator becomes less, there is a pressure drop across the little venturi system where the siphon tube and return tubes meet, and the siphon effect takes place, pulling fuel from that side of the tank into the main tank.

It is super easy to kink the main line when removing the hanger assembly and as such, it is hard to find one in good shape. If you are going to use an external pump and AN fittings/lines you'll be able to find a cheap one like that (I have one with a kinked line for cheap if needed), but I would definitely not screw with the stock siphon and return setup because of its complexity. The little venturi that sits on the side of the hanger can be drilled out a certain amount if you are really going big on the fuel supply, but be careful because too big of a new hole and you'll loose the correct pressure for the siphon effect to take place and have fuel sitting in the driver's side saddle forever LOL!
 
Great explanation Fullthrottle7! Thanks.

So does the return line connect to the siphon line going between the two 'compartments' of the fuel tank?

1G Eclipse94928: cool, do you know wich ones?
 
The return comes right back to the hanger and the siphon system is the third input you see on top of the hanger assembly that the FWDs dont have. Here is a great write up on the whole setup its quick and easy and really gives you a good knowledge base to prepare you for modding it all properly: http://www.dsmtuners.com/forums/articles-engine-fuel/470263-2g-awd-dsm-fuel-system-de-mystified.html

Last thing you want is to screw up the simple yet effective factory engineering and really have to dig in to mod everything attached. I've seen guys spend $1000 many times doing their whole fuel system with stainless lines and AN fittings. Turns out great but I'm a cheap ass LOL. Enjoy the project!

- Tyler
 
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