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Running turbo injectors with NA ECU and more...

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  • Running turbo injectors with NA ECU and more...

    So this is what happened. I did my NA to T swap and had the car running for a few months. Ran a best of 13.7 at 12 PSI and I was happy. Then the ECU started crapping out, but only when it rained. It was really weird actually. First time it happened was after a heavy rain. I got to my buddy's house, had a couple beer and when I got out, the car just ran like shit all of a sudden. It was misfiring like crazy and blowing insane amount of black smoke. I barely got it to school the next morning and threw the scope on it. It was running around 6:1 AFR. All of my instructors looked at it and nobody could figure it out. I left it there for the day and when I got back, it was magically running great again (after I burnt the carbon off the plugs with a propane torch). I opened up the ECU and found out that it was full of water and everything was corroded. Cleaned it up nice and wrapped it in plastic, but every time it rained after that the car would run like crap. There was definitely no water in the ECU anymore, so it seems like just the moisture in the air was causing it somehow, nobody at my work or school could tell me why. It was time to look for a new ECU.


    I bought one off E-bay and the guy advertised it as a 85 Turbo computer. I was driving my car during a rain and the old ECU crapped out again. i plugged the new "85 turbo" computer in and got to work no problem. That day I noticed that the car was not idling as good and backfiring a lot more than before. I just disregarded that thinking that the plugs got fouled again and cleaned them up. Nothing changed. The car was running OK, but blowing some black smoke and backfiring. I got it to the track that Friday and got a bad surprise. Even with higher boost (15 PSI) I could not run faster than a 13.8. I was pretty frustrated. I kept driving the car for a month, clocking over 3000 mi on it. Took it to the track a few time and no matter what I could not run faster than a 13.8. Finally I checked the numbers on the ECU and found out that my "85T" was actually an 87 NA.


    I calculated the AFRs from the injector sizes and found out that I was running about 11:1 at no load and 9:1 at full load :?
    I did not have another ECU, so I had to do with what I had. Here is a way to run your turbo injectors with an NA ECU half decently.
    Take the AFM. Take out the fron wire screen on it. Take a regular pop bottle. Cut off the neck on which the cap screws on. Stick the cap into the AFM sampling tube all the way to the intake air temp sensor, the pop bottle threaded tube will fit in perfectly. Put the AFM back into your car. Now it will think that there is less air running thru, and open the 260 cc injectors for a shorter time, approximately matching the AFRs to the correct spec.

    Of course, this is a band-aid fix, but it is working for me for the next week until I get a turbo ECU from Raidon.
    13.729 @ 102.90
    http://z31.com/board/print_profile.php3?user_id=872

  • #2
    Hey, not a bad idea. Your fix is perfectly akin to the many other methods to untimately reduce the maf voltages, leaning out the mixture and also allowing more metering ability. That's actually a very interesting way, blocking air around the element. I'm not sure if it's really ideal; but like you said it should work.

    I know you are only using it short-term... The only problems I see with the long-term usage of a setup like this reltaes to the N/A timing maps and corresponding load value (and hence ultimately the TP scaling of the timing map) with the voltage reduced maf as well as the new "shape" of your maf output voltage curve because of the mod.

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    • #3
      Re: Running turbo infectors with NA ECU and more...

      Russian wrote: but every time it rained after that the car would run like crap.
      Check to see if the windshield is leaking. The same thing happenned to my car when the girl owned the car before me. It is not easy to see the windshield leak. The water runs down the inside of the A-pillar and gets into the connectors into the ECU and shorting them out. It took three repair shops and about six months to figure out what was happening.

      Comment


      • #4
        Thank you for the suggestion. The windshield was actually leaking, that is how the water got into the ECU initially. After I dried it though, I hung it up to the dash with zip ties to make absolutely sure no water reaches is. It still crapped out every time it rained heavily. No water on or inside the computer at all.
        13.729 @ 102.90
        http://z31.com/board/print_profile.php3?user_id=872

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        • #5
          Here's a suggestion, perhaps instead of working around the leak why not fix it? :P
          http://youtube.com/c/zcartube

          Comment


          • #6
            I have fixed it since then. Ripped out all the moulding and filled the space with a full tube of black silicone out of a caulking gun. Ugly but functional, like the rest of my car :wink:
            13.729 @ 102.90
            http://z31.com/board/print_profile.php3?user_id=872

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            • #7
              hahaha infectors...that is brilliantly mispelled, i like it.

              Terrible idea putting those wheels on...

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              • #8
                A turbo ecu will not run NA injectors either from what I hear (86t ecu with post recall low resistance injectors). Its just too lean and the ecu control can not fatten up the PWM enough.
                Try not to be a Yahoo

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                • #9
                  it can, but it won't.... it's all in the maps 84-87 ecus are all low impedance

                  *edit* this begs the question, crowbar you seem to have a very twisted understanding of the z, and I actually can't fathom why, it seems like you grasp some principles and complex functions and then either don't get or ignore others?

                  Comment


                  • #10
                    crowbar wrote: A turbo ecu will not run NA injectors either from what I hear (86t ecu with post recall low resistance injectors). Its just too lean and the ecu control can not fatten up the PWM enough.
                    Seen it done. He was driving it that way for a week before I came down and threw my wideband on it. Running 18-19.0+AFR's, but running.

                    an hour later I had his issue 100% cleared up and running far better than stock. All problems are solvable with time and the correct equipment.

                    Comment


                    • #11
                      G-E wrote: it can, but it won't.... it's all in the maps 84-87 ecus are all low impedance

                      *edit* this begs the question, crowbar you seem to have a very twisted understanding of the z, and I actually can't fathom why, it seems like you grasp some principles and complex functions and then either don't get or ignore others?
                      Too easy. I will let this go. I understand you are already smarting for acusing me of reading comprehension and then being schooled.

                      http://www.redz31.com/forum/viewtopic.p ... c&start=18
                      Try not to be a Yahoo

                      Comment


                      • #12
                        [quote]Jason84NA2T wrote:
                        Originally posted by crowbar
                        A turbo ecu will not run NA injectors either from what I hear (86t ecu with post recall low resistance injectors). Its just too lean and the ecu control can not fatten up the PWM enough.
                        Seen it done. He was driving it that way for a week before I came down and threw my wideband on it. Running 18-19.0+AFR's, but running.

                        an hour later I had his issue 100% cleared up and running far better than stock. All problems are solvable with time and the correct equipment.
                        (OK some humor)

                        Did you put the cut up sodey bottle in backwards?
                        Try not to be a Yahoo

                        Comment


                        • #13
                          crowbar wrote: (OK some humor)

                          Did you put the cut up sodey bottle in backwards?
                          :lol:

                          That was actually pretty damn funny.

                          No, I just adjusted the K value, tp scales, fuel and timing maps. The (na) car picked up easily 20hp and pulled to 7K like it was nothing. Fasteset NA I have ever driven.
                          Attached Files

                          Comment


                          • #14
                            crowbar wrote:
                            Too easy. I will let this go. I understand you are already smarting for acusing me of reading comprehension and then being schooled.

                            http://www.redz31.com/forum/viewtopic.p ... c&start=18
                            unlike you I have no ego in the common usage sense, I don't get offended or insulted, if it seems like it, it's just to please expectations and has no effect on me in the slightest

                            I don't suffer from road rage no matter how stupid drivers are, I rarely use the horn and never in anger, sometimes to be annoying but that's a choice like slapping a kid's hand away from fire, not revenge

                            you can say whatever you want, and like I said I still can't grasp how you can only grasp parts of the ideas we've been discussing, I see a horse and you see some leg muscle near some hair.... that's about how I'm reading your analyses... the rest is mindless drivel we don't need

                            I suggest a cleanup on engine management aisle..... when someone feels it appropriate

                            Comment


                            • #15
                              [quote]Jason84NA2T wrote:
                              Originally posted by crowbar
                              (OK some humor)

                              Did you put the cut up sodey bottle in backwards?
                              :lol:

                              That was actually pretty damn funny.

                              No, I just adjusted the K value, tp scales, fuel and timing maps. The (na) car picked up easily 20hp and pulled to 7K like it was nothing. Fasteset NA I have ever driven.

                              Glad you have a sense of humor.

                              I have a 88T ecu that I want to run on a NA car. I plan to use your fuel injection mod where you 'over-size' fuel lines over injectors. I plan to use high resistance injectors 370cc from KA24 engines. These modded into a top feed rail from a 300zx car.

                              The NA car should
                              run fine I assume? The ecu should run closed loop even though there would never be any boost in the 'load' calc? My car uses the smaller O2 sensor (like a 86 300zx NA does) and has a 3.90 rear.
                              Try not to be a Yahoo

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