The Top DSM Community on the Web

For 1990-1999 Mitsubishi Eclipse, Eagle Talon, Plymouth Laser, and Galant VR-4 Owners. Log in to remove most ads.

Please Support Fuel Injector Clinic
Please Support ExtremePSI

Fuel line routing

This site may earn a commission from merchant
affiliate links, including eBay, Amazon, and others.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

reborn750

10+ Year Contributor
106
1
Oct 7, 2010
Brookings, South_Dakota
I have read a few other posts regarding fuel line routing but still have some questions. The car is a 98 gs. The way the po had the car setup is how it sets now except for the fuel pump swap. It is a wally 255 fp, the feed line runs to the stock filter/fpr, this then runs directly to the fuel rail. Then there is no return line from the rail whatsoever. I see what looks to be a schrader valve capped off on the fuel rail as seen in the below pic. (sorry for picture quality)

You must be logged in to view this image or video.


Is this the return port? Close by at the lower passenger firewall is a hard line that was cut from somewhere, I followed it all the way back to the fuel fill neck.

You must be logged in to view this image or video.


Do i run the return to this, or the return on top of the pump next to the feed line? Right now it looks like the return line on top of the pump runs right to the stock filter/regulator? Both lines from on top of the tank run to it but only the feed line to the rail comes out of it.

You must be logged in to view this image or video.


I plan on running a SS line from the pump feed straight to the fuel rail, but for the return line I would like some guidance on what to do. I do have an aftemarket afpr, and a pressure gauge that I would like to put on the return line.

Right now the car does start and idle for a few seconds before dying. After initial start up the car struggles but never actually starts again until it has sat for quite some time. I am hoping new gas and running my fuel lines will help out my situation.
 
From researching a few posts I've seen some people saying some 420a's don't have a return on the fuel rail? 97-99? How does that work? Could this be my problem, if soo what years fuel rail should I be looking for, ide like a stock one as I've heard nothing good from aftermarket rails. On dsmforums one member posted that you can simply remove the schrader valve and run a return line from this to an afpr then to the return on the tank.
 
I think that 95-96 they do have return line, but 97-99 they don't. One question, why do you want to run a 255 fuel pump? I don’t think it will a good idea, you will need a fpr. Your fpr will not hold the pressure.
 
I am running the 255 to feed my turbo build. I read up on returnless systems and found that they are often regulated by a pressure sensor that tells the regulates pump output, etc. Well because I am running a standalone ms ecu I have no pressure sensor. Because of the 255 and no factory pcm anymore this means I need to run a return type fuel system correct?
 
There is a return line but its by the regulator in the passenger wheel well. Best way to do it is take the schrader valve out of the test port on the end of the fuel rail and screw a 4-AN fitting to it and run a return line back to the tank. So it goes from the fuel pump to the fuel rail from the rail to the fuel pressure regulator then from the regulator to the return on the tank.
 
I always wonder, since you might already did an vacuum deleted. Can you used the line that comes from the tank to the evaporate system? You can disconnect the line on the tank and use that line as your return line. I was going to try that when I had my 420 but I never had the chance to test this theory.
 
With a 420a you don't need a afpr because the stock regulator won't over run. The 255 stock is fine.
 
Dont I need an afpr to compensate for high boost? I plan on removing the stock filter/regulator.
 
When I had my 420, I was about to do the turbo and I know that you need to do the aftermarket fpr and the fmu to compensate the boost. Plus it will be nicer, removed the stock fpr and add the afpr by the engine that way you see the exact fuel pressure and you can control the pressure.
 
When I had my 420, I was about to do the turbo and I know that you need to do the aftermarket fpr and the fmu to compensate the boost. Plus it will be nicer, removed the stock fpr and add the afpr by the engine that way you see the exact fuel pressure and you can control the pressure.

The FMU is not required. It depends on what engine management he is running. And to see the exact fuel pressure, you are assuming there is a gauge on the AFPR - depending on the model/brand used the gauge is not included or required for operation.
 
yes i am running ms, i will be buying a 1:1 aeromotive. I have an ebay afpr right now but prefer to not run ebay parts if i dont have to so im swapping it.
 
Support Vendors who Support the DSM Community
Boosted Fabrication ECM Tuning ExtremePSI Fuel Injector Clinic Innovation Products Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications MyMitsubishiStore.com RixRacing RockAuto RTM Racing STM Tuned

Latest posts

Build Thread Updates

Vendor Updates

Latest Classifieds

Back
Top