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where should my fuel pressure be?

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    where should my fuel pressure be?

    hi everyone

    i did a quick search and could not find any answers -

    S2S2 Cams
    High Comp Valves
    Milled Head X2
    S2 Dual Springs
    AEM Fuel Rail & FPR

    not sure what, if any of that information you may need.

    i KNOW i am running rich as hell (i can smell it plus the black smoke) at the moment and need to know where i should be? i think the pressure it around 40+/-??

    thank for any and all help


    EDIT: in doing some research on hondatech it looks like it may be set WELL too low - one guy is runnin 44-46 psi on stock compression....i think i am really really low here...can someone fill me in before i change it - am i dont any ill will do my car having it so low?

    thankx again!
    Last edited by 13pulgadas; 17 Jun 2010, 18:46:06.

    I'm running mine pretty high, around 55psi. (b17a, 11:1, ITR cams, 188whp). I originally had it turned up this high to help it idle better when I first swapped in the engine and did my break-in. During my tune I forgot to mention this to the tuner until the end and he said it didn't need to be changed, that the ecu would compensate based on his tuning and that the fp could be left alone. Obviously if it's way too low then that wouldn't be the case.

    Have you looked up the fuel pressure specs for a stock b18c? I'd start with that and move up if needed.

    You said you're running rich, have you had the engine tuned on a dyno? With the mods you have you NEED to have it tuned on a dyno in order for it to run properly. Unless you're really good with a datalogger and/or afc type device.


      hey colin

      thanks a lot for the response. it looks like stock specs are:

      B18C1 engine:
      48-55 psi (with the fuel pressure regulator vacuum hose disconnected and pinched.)

      so i will def raise it up from 40 where it is currently at.

      and, no unfortunetly i have NOT had it tuned yet. however, that is the plan for this year. i want to get everything in working order, or at least as much as i can, before i have iot tuned as it will be a huge chunk of $ outta the budget lol

      i actually still have me VAFC II as well as my Greddy Emanage...neither are currently installed though. i probably could install the greddy and tune it via laptop? not me, hopefully i can find someone who knows what they are diong lol

      and wow man, that b17a must really skoot!! how do u like the ITR cams?? i wonder what my comp ratio is....hmm

      thanks for the help! always appreciate hearing from you man


      i just came upon this jewl of info:

      B18C1 engines through 1997
      With regulator vacuum hose attached - 39 to 46 psi
      With regulator vacuum hose disconnected - 48 to 55 psi

      B18C1/B18C5 engines through 98+
      With regulator vacuum hose attached - 38-46 psi
      With regulator vacuum hose disconnected - 47-54 ps

      i know im a 98 B18C so im going to change the FP as soon as i get out of work and see what it does. hopefully does something lol - ive got a lot of backfire everytime i lift my foot of the gas and put it slightly back it tho, scares people in the inner city lol


        I would put tuning at the top of your list. My tuner charges a "flat rate" Honda tuning fee, if using Hondata or Chrome it runs $300-$350 (+$50 for cam gears). That's a lot cheaper than building a new motor because you waited too long to get your tune. Trust me, it happened to me. Ran rich, didn't think much about it, I was young and poor. Motor didn't last 30k mi until my compression was really low. This time around I put just enough miles on the engine to get it barely broken in (about 300) and then got it on the dyno ASAP.

        Are you just running a stock ecu right now? The vafc would be better than nothing but personally I've never used one so if it were me I'd need to do a bunch of research on how to use it properly.

        Have you checked your plugs? Smell and soot aren't the best ways to determine if you're running rich. My car belches out soot and dirties my bumper, but I'm not running rich.

        You need to calculate your compression ratio, you should have done that before you put the engine together. You really should pick your CR, then purchase parts, not just purchase parts and then deal with whatever CR you end up with.

        My engine feels really good, it's producing a lot more power than I was expecting (by nearly 20whp), so I'm very happy with it. I'm using a CTR intake cam and stock p61 exhaust cam (out of necessity, not so much choice). Combo feels good, but I don't have anything to compare it to since it was nearly 8yrs ago since I'd driven the engine w/ the stock cams.


          Tuning has just births top of the list. I am actually selling my dd so I will use the money from that to get it done! I've been wanting to do it since I've had the car, the funds were always the provelm.

          The ecu is not stock the shop has it chippped when I put the motor in. Now when I say chipped I don't really know exactly what they did, so i def need to get it done.

          I have not checked plugs but I will be adding that to my todo list for Saturday! I will actually be replacing them..

          As far is the cr is concerned I have o calculate it. I will be lookking that up in the morninng foe sure.the engine wass built about2-3 years ago but it does not have hat many miles on it. That said I don't want to shorten it's life span!

          Glad to heat that about your engine man. Gotta love getting mor than you expect especially hp wise haha it really shows you know your stuff and enjoy doing it. I really appreciate the help and advice man.

          Thanks again


            hello again

            i just looked up on the forum for my old post about my comp. test i did back 3 years ago (almost exac to the date!) but anyhow, at that point in time my #'s were at 235 all across the board (may 230 on one of them)

            i will be redoing the test this weekend. i will first:

            up my FP to 44-46 with hose attached
            change my plugs

            i would like to seafoam, but as i just changed my oil ill wait until late next month.

            thats a great price youve got for tuning man! i wish i lived on the west coast hahah- im actually going to start looking today for someplace to get it tuned where i am (upstate NY) - - - i hope to get it tuned next youve got me worried! i dont want me baby to blow up on me! i almost want to just leave work now and go to do my comp test! lol

            actually i think im going to do a test before i change everything and one after, just to see if there is a difference. i will do the initial test after work, so ill post up then what the #'s are...god im hoping they aren't much lower than the 235....

            thanks again for the help and advice


            i just did some searching of my old posts -

            i will also be finally WIRING my KS this weekend! ive had that dam CEL blink 23 at me for well too long!!!
            and a wash n wax

            anyother ideas for gen. maintenance?
            Last edited by 13pulgadas; 18 Jun 2010, 15:56:57.


              Since you already have a VAFC, you could get a wideband O2 that is capable of datalogging and use those two things in conjunction to get your fuel a little closer to where it should be.

              If you check out the thread I started in the Hybrids forum about my proposed B17 build, you will see a dyno graph that I post of a friend's car. The before curve is the tune my friend did (with no previous experience) using a datalogger, wideband O2 and an iPhone app that is supposed to calculate horsepower (I know, right?). As you can see from the before and after, it is possible to get a pretty decent tune yourself with the proper tools. Although, you can also see that while the lines themselves on those two tunes don't look very different, he was able to get a pretty noticeable change in area under the curves by having a professional take a crack at it. Although his B16 is stock with CTR cams and stock pulleys. With the headwork you have had done, you actually need to get your cams degreed properly if they haven't been already.

              You will spend more money the way I suggest doing it though; the first wideband setup like that I was able to find was $429 and you would still need a tune later, so you might as well just do it right this time around.


                hey everyone

                i did raise my FP to about 47-48 with the hose on.

                i also changed my spark plugs...which were FOULED very badly. i saved them to snap some pix, and i will do that when i get home and post them up...

                i did notice, with the changing of both above, that the car seemed 'more solid'. in saying that i mean it didn't seem to shake as violently at idle and seemed to pull a bit more steady at lower RPM's.

                buymysoul - thanks for the info man! i am def looking to go the less expensive way. although i know that it will not be cheap either way by any means....

                however, since we are on the topic. do i need something to get my teg tuned? do i need a wideband? or should i try to wire the Greddy EMANAGE system back up. ive looked around and there are 2 places within a hour that tune....1 doesn't do Honda's and the other im still trying to reach.

                thank for all the help guys!


                  You will need a WideBand if you're going to tune it yourself with the VAFC or by other means that are similar.. If you're going to take the car to someone to get tuned (Dyno'd, hopefully) Then they will have a WideBand that they will use when they tune the car.

                  It would obviously be best if you could go to someone familiar with tuning Hondas.. As people have already mentioned, tuning is going to be one of, if not THE most important aspect of any engine build. Going cheap on the tune will not only miss out on the full potential of your setup, but it may be hazardous to the health and longevity of your motor.


                    unified112 - thanks for the info man! i will def not be the one tuning it. i will have it prof. done. and on a dyno. i am on a local forum here and ran across someone who has been tuning hondas almost longer than ive been around. i just sent him an email and am waiting to hear back from him, really really excited to see what kind of power im getting....