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1g FPR and W 255

Posted by nuclearr, Dec 11, 2010

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  1. nuclearr

    nuclearr Proven Member

    1,201
    11
    Joined Jun 22, 2004
    Slidell, Louisiana
    What makes it that some 1gs do not have an issue running a 255 on the stock FPR?

    Is it just a better stock FPR?

    I had a 90 tsi fwd with a 255 and had no issues with it running rich.
     

    Street Build 1K  2

    1996 Mitsubishi Eclipse Spyder GST
    awd · manual · 2G DSM
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  2. Black95TSIawd

    Black95TSIawd Proven Member

    1,719
    351
    Joined Jan 28, 2003
    Dirty, New Jersey
    For the most part, it has nothing to do with the FPR. 2g's have a problem due to the siphon in the fuel tank that is used to bring fuel to the fuel pump from the other side of the saddle. That siphon is very small and once a high pressure fuel pump is included into the mix, the system backs up.
     

    5K  8

    1998 Eagle Talon TSi AWD
    184.4 whp · 251.0 lb/ft · 2G DSM
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  3. Imback

    Imback Proven Member

    902
    21
    Joined Nov 8, 2006
    Elmont, New York
    Correct. I have a 255 and am still using my stock FPR with no issue.
     

    668  0

    1995 Eagle Talon TSi AWD
    manual · 2G DSM
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  4. MindBlowin03

    MindBlowin03 Proven Member

    451
    34
    Joined Apr 11, 2002
    Peckville, Pennsylvania
    Its not that you would have issues but its certainly not the best way to do things. When you install a 255 pump your low and mid fuel trims are way out of whack weather you know it or not.
     

    2K  5

    1998 Mitsubishi Eclipse Spyder GST
    fwd · manual · 2G DSM

    3K  10

    1997 Eagle Talon TSi AWD
    608 whp · 510 lb/ft · 2G DSM
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  5. Imback

    Imback Proven Member

    902
    21
    Joined Nov 8, 2006
    Elmont, New York
    The low and mid fuel trims are easy to get back in spec if you know what your doing. And my low and mid did not change much after installing the 255.
     

    668  0

    1995 Eagle Talon TSi AWD
    manual · 2G DSM
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  6. olddsmer

    olddsmer Proven Member

    151
    1
    Joined Mar 26, 2010
    middletown, Ohio
    Normally the 255 will overrun the 1g fpr. The diaphram usually weakens and
    you start to run rich. Most reputable shops will tell you to put in an AFPR.


    Regards
    Greg
     
  7. nuclearr

    nuclearr Proven Member

    1,201
    11
    Joined Jun 22, 2004
    Slidell, Louisiana
    I know that I am running rich in my 2g with the 255. I was asking because I do have the stock fuel rail off my 90 gsx which I scraped about a year ago.

    I know I need a AFPR I am just trying to get the car running to test drive the AWD swap which is nearly complete.
     

    Street Build 1K  2

    1996 Mitsubishi Eclipse Spyder GST
    awd · manual · 2G DSM
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  8. MindBlowin03

    MindBlowin03 Proven Member

    451
    34
    Joined Apr 11, 2002
    Peckville, Pennsylvania
    Agreed. You can usually tune that out if you have just a little bit knowledge.

    Have you drilled the syphon hole bigger yet? If not it is very easy and literally only takes about 30-45 minutes total to do. I would definitely do that.
     

    2K  5

    1998 Mitsubishi Eclipse Spyder GST
    fwd · manual · 2G DSM

    3K  10

    1997 Eagle Talon TSi AWD
    608 whp · 510 lb/ft · 2G DSM
    Loading...
  9. 1badpurple

    1badpurple Proven Member

    217
    1
    Joined Jul 15, 2010
    lillian, Alabama
    I was running the stock fpr with my wally pump. The diaphragm would eventually bust and I would just throw another stocker on.
     
  10. diambo4life

    diambo4life Proven Member

    1,022
    73
    Joined Apr 18, 2002
    Edmond, Oklahoma
    No idea why you guys are having so much trouble with your stock FPRs. Here's what I have in my car:
    • Bosch 044 Motorsports fuel pump (setup in the tank)
    • Stock feedline to fuel filter.
    • Stock fuel filter w/-6AN fitting on top.
    • Walbro 255 inline pump (aka 392) [located bwtween stock fuel filter and fuel rail]
    • 3/8" fuel line between fuel filter and fuel rail which has -6AN fitting only on the entry side.
    • Four 1,600cc/m injectors.
    • Stock FPR.
    • Stock fuel return line.
    Both pumps rewired (14.0-14.5VDC @ idle)

    No problems. Car's run primarily on E85 although I run pump gas in it during winter months. No issues. Been doing so for 3 years now and I regularly run 35psi+ boost. ROFL
     

    Street Build 4K  23

    1991 Mitsubishi Galant VR-4
    788 whp · 588 lb/ft · Galant VR-4

    Drag Race Build 885  1

    1990 Mitsubishi Eclipse GSX
    manual · 1G DSM
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  11. Bricktop

    Bricktop Proven Member

    164
    3
    Joined Aug 24, 2009
    Corydon, Indiana
    Ditto. I'm only running a rewired Supra TT pump and a Stock fpr,return. still working great after 1.5 years.:thumb:
     
  12. nuclearr

    nuclearr Proven Member

    1,201
    11
    Joined Jun 22, 2004
    Slidell, Louisiana
    I am not familiar with that mod. Do you happen to have a link?

    But what does the siphon have to do with running rich on a stock FPR?

    I have heard that before thanks. Brian

    I see you sold your car what did you replace it with?
     

    Street Build 1K  2

    1996 Mitsubishi Eclipse Spyder GST
    awd · manual · 2G DSM
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  13. iugrad92turbo

    iugrad92turbo Supporting Member

    10,549
    439
    Joined May 22, 2007
    Kalamazoo, Michigan
    When i got my wally i had to get the afpr, i was running rich problem solved.
     

    7K  5

    1992 Eagle Talon TSi
    awd · manual · 1G DSM
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  14. magik95

    magik95 Proven Member

    238
    1
    Joined Feb 24, 2008
    aurora, Colorado
    Today I had drilled out the siphon hole to 1/8 because I was running seriously rich because the return was backed up.

    I originaly thought my afpr was crap so I took it off put the stock fpr back on same problem. Now that I dilled out the siphon it is a 100% better. Also the afpr would not adjust before I drilled the siphon now
    it does.
     
    Last edited by a moderator: Jul 10, 2014

    269  0

    1995 Eagle Talon TSi AWD
    · 2G DSM
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  15. nuclearr

    nuclearr Proven Member

    1,201
    11
    Joined Jun 22, 2004
    Slidell, Louisiana
    Thanks I did not know about this I already have my rear seat out and the inspection plate off so it will be easy to drill the siphon pick up.

    I know I need a AFPR, but I do not have a stock fuel pump right now I had to get new pump and fuel senders as the ones in the tank went bad from siting. The pump I got came with a 255 on it.
     

    Street Build 1K  2

    1996 Mitsubishi Eclipse Spyder GST
    awd · manual · 2G DSM
    Loading...
  16. 1badpurple

    1badpurple Proven Member

    217
    1
    Joined Jul 15, 2010
    lillian, Alabama
    Yea I did sell the car. Its ok though, I replaced it with a 91 gsx!
     

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