Help with injectors...

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  • ForcedFirebird
    Live life 3.7mi at a time
    • Jan 2007
    • 4555

    #1

    Help with injectors...

    Hey guys, been looking here for a while - this is my first post.
    Just finished installing some small block Ford 1.7 rockers on the firebird (3.1 LHO),some 24# blue top injectors and an Adjustable Fuel Pressur Regulator. Now idle isn't happening and running rich even with the stock FPR low as it can go. I was hoping it could be done mechanically untill I get MegaSquirt going.
    .
    Any suggestions would be greatly appreciated.
    Last edited by ForcedFirebird; 01-21-2007, 05:49 PM.
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  • treeZ24
    i wanna go fast!
    • Mar 2004
    • 251

    #2
    what pressure did you turn the injectors down to. because i don't think they are going to like being below 30psi iirc ford rates them at what, 38#?
    got zap-straps?
    89 Z24
    13.886 @ 96.16 mph
    street trim - slicks

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    • ForcedFirebird
      Live life 3.7mi at a time
      • Jan 2007
      • 4555

      #3
      Originally posted by treeZ24 View Post
      what pressure did you turn the injectors down to. because i don't think they are going to like being below 30psi iirc ford rates them at what, 38#?
      Haven't checked the pressure yet, got tired after the rocker install. While I was at it, painted the UIM. I turned the stock FPR down as far as it would go. And yes the Ford injectors are underrated in comparison the GM's. I'm surprised you didn't ask about the SBFord 1.7 roller rocker arms I found that work on the pushrod 60*...
      They were $69 delivered and bolted on using the stock pivot balls and locking nuts, not to mention they fit under the stocker valve covers.
      After some discussion on another site it was suggested to "gut" the factory FPR and rely on the aftermarket one.
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      • Azrael
        Accelerating uphill in OD
        • Apr 2005
        • 763

        #4
        It's awesome that the ford rockers fit. But the question is, do they match up geometry-wise?
        1995 Grand Am SE

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        • bszopi
          Site Coder
          • Apr 2000
          • 9179

          #5
          They fit on a 3.1 from a Firebird, ie a iron head engine. There are alot of rocker that will fit the non-splayed valve heads. Its the aluminum heads that it is hard to find rockers that will work.
          -Brad-
          89 Mustang : Future 60V6 Power

          Follow the build -> http://www.3x00swap.com/index.php?page=mustang-blog

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          • XLR8ING
            Too Stupid To Quit!
            • Oct 2003
            • 268

            #6
            I used to have the 24# blue tops.
            Without proper computer control, I think you're gonna have to go back to stock injectors. 24 is just too big unfortunately.
            Franz

            1990 Z24-NA 3.1L
            14.72 @ 92.24 MPH
            14.89 @ 94.92 MPH

            The boost is coming....

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            • boostedrs
              • Mar 2006
              • 168

              #7
              u can use 24#'s but u need to drop the base fp,its not optimal but it does work,i have done it and other ppl on tgo have done it,it will run slightly rich @idle though.
              mainly his problem is he installed a afpr in the return line from the fuel rail,the stock fpr is still installed holding the fp @ 42-45 psi.also with i beilve u will see decreased vacum from the 1.7's which will also make the stock fpr increase fp slightly
              sigpic

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              • treeZ24
                i wanna go fast!
                • Mar 2004
                • 251

                #8
                i'm already using the gold race series rockers, + as other guys said i also have aluminum heads and there's not very much space.

                i would be more concerned about the fact the only mods are the rockers, on an iron head 3.1 engine and you have 24# injectors. i'm pushing 200hp and 24# injectors are perfect for my application running 85%

                if anything i would be more inclined to go back to the 16# injectors and bump your pressure UP until you get your MS working. the other thing with dropping the base fuel pressure without knowing what it is, when you get the vac reference to drop the pressure further at idle the quality of the fuel pattern coming from the injector will be pretty poor. practically pouring fuel into the intake rather then atomizing the fuel as it is supposed to be.
                got zap-straps?
                89 Z24
                13.886 @ 96.16 mph
                street trim - slicks

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                • sharkey
                  • Jun 2004
                  • 2061

                  #9
                  stock computer and 50% bigger injectors is not going to work. i tried running 19lb injectors on my built motor before tuning and it idled very rich, stumbled all the time. when it finaly cleared out around 4500rpm it went like a bat outa hell. it wasnt until i got my megasquirt in that i was able to use these injectors.

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                  • boostedrs
                    • Mar 2006
                    • 168

                    #10
                    hes going turbocharged shortly,thats why he droped the injectors in the motor,while he had the manifold apart to install the rockers. im pretty sure the car isnt his daily driver
                    sigpic

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                    • ForcedFirebird
                      Live life 3.7mi at a time
                      • Jan 2007
                      • 4555

                      #11
                      Hey dave! Thought I might see you here.
                      No the Firebird is one of my four vehicles, and would like to get the turbo installed soon. And yes the reason I changed injectors already is because I had the top of the motor apart. I might go back with the stock injectors just so I can go to the track on Wed. and see if there's any difference with the 1.7's
                      Last edited by ForcedFirebird; 01-21-2007, 05:45 PM.
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                      • ForcedFirebird
                        Live life 3.7mi at a time
                        • Jan 2007
                        • 4555

                        #12
                        Gutted the stock FPR and the car idled today, but it's throwing code 33 (low vac @ MAP). To get the vacuum for the AFPR, I tee'd off the window washer and off the MAP and neither worked (to correct code).
                        .
                        Help, please?
                        .
                        BTW, could it be because of the lopy idle I'm getting since the rocker swap?
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                        • 1988GTU
                          LB62LHObbqftmfw
                          • Nov 2005
                          • 2475

                          #13
                          Why couldn't you use the vacuum from where the old fpr once connected too?

                          Yes the rockers would be more than likely giving you a slightly more lope. I know the 1.6's did for mine.
                          Lifting my front wheels, one jack at a time.

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                          • ForcedFirebird
                            Live life 3.7mi at a time
                            • Jan 2007
                            • 4555

                            #14
                            Did it throw a 33 code at idle? Vac at the stock location on the throttle body seemed to be low for the AFPR, but I'll try that again and get back. Thanx 1988GTU!
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                            • 1988GTU
                              LB62LHObbqftmfw
                              • Nov 2005
                              • 2475

                              #15
                              no codes.... as of yet. I do expect a failing O2 soon since it does run rich.
                              Lifting my front wheels, one jack at a time.

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