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Would a gen 1 3.4 run with no cam sensor as MPFI?

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  • Would a gen 1 3.4 run with no cam sensor as MPFI?

    Question says it all, basically I am between rock and a hard place, I attempted a '165 ECU swap, and for reasons not quite known it was unsuccessful, I am still weighing my options as to how I am going to remedy it and get my car running again.
    One option I am considering is swapping a full wiring harness and ECU from a 93 3.4 fbody, however I would really rather not tear my engine apart to put a stock cam in it.

    My question is:
    If I have no cam reluctor and or cam position sensor, will it simply revert to MPFI and throw a code, or would it not even run? SFI just is not worth yanking the cam out for to put a weaker one in, if it would run fine without and just revert to mpfi. But I really don't know if the ECU is capable of falling back on MPFI like that.
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  • #2
    You would be kicking yourself in the hiney if you go with OBD1.5. Is there a reason you don;t swap to the 90-92 1227730 ECM?

    But, to answer your question, yes the 1.5 ECM will just revert to batch fire and your SES light will always be on. It will handle a light cam even (262).
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    • #3
      '7730 ecm swap is the answer to your problem.. Just re-pin the harness, plug it in and have someone burn you a chip.
      Past Builds;
      1991 Z24, 3500/5 Spd. 275WHP/259WTQ 13.07@108 MPH
      1989 Camaro RS, ITB-3500/700R4. 263WHP/263WTQ 13.52@99.2 MPH
      Current Project;
      1972 Nova 12.73@105.7 MPH

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      • #4
        Originally posted by Superdave View Post
        '7730 ecm swap is the answer to your problem.. Just re-pin the harness, plug it in and have someone burn you a chip.
        Already been there done that with a '165, sick of the complications, at this point I just want my gd car to run, preferably with DIS, I KNOW that the ECU and harness built for that motor will run it with DIS. Currently it will NOT run with my attempted '165 ECU swap, I am not keen on going back down that road again with yet another, entirely different ECU swap, after all the trouble this attempt was, and not even successful. So unless somebody lives in pittsburgh and would be willing to work out an arrangement to either get the one it has working or a 730, then I have less than 0 interest attempting anything that isn't plug and play with known good components. I have no idea why my swap failed, I know the problem, but without the cause its useless information. My injectors pulse way to fast, and cut out the moment it starts to catch and run. Like I said, atm, I just want it to freaking run again.

        And thanks for the answer, also fyi, someone is working on cracking obd 1.5 fwiw, and I also meant to ask, whether or not the SES light can be disabled with tuning?
        Last edited by 2.8/3400 1985 Camaro; 10-13-2011, 06:16 PM.
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        • #5
          It sounds like you just have both banks of injectors shorted together. D15 is the grounds for 1,3,5 and D16 is the grounds for 2,4,6, on that ECM. If you shorted those 2 leads together the injectors will do exactly what you say they are doing.


          BTW, I don't remember what ECM a '88 2.8 Camaro had but MarsMan posted a quick reference for the pinout changes in the plugs to convert it to a '7730. It looked very easy. It's in this thread somewhere.. http://www.v6z24.com/jbodyforum/also...t-t112374.html
          Past Builds;
          1991 Z24, 3500/5 Spd. 275WHP/259WTQ 13.07@108 MPH
          1989 Camaro RS, ITB-3500/700R4. 263WHP/263WTQ 13.52@99.2 MPH
          Current Project;
          1972 Nova 12.73@105.7 MPH

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          • #6
            Part of the difficulty in that is that there are redundant INJ wires, but I am pretty certain I covered all possible permutations between them.
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            • #7
              Originally posted by 2.8/3400 1985 Camaro View Post
              Already been there done that with a '165, sick of the complications, at this point I just want my gd car to run, preferably with DIS, I KNOW that the ECU and harness built for that motor will run it with DIS. Currently it will NOT run with my attempted '165 ECU swap, I am not keen on going back down that road again with yet another, entirely different ECU swap, after all the trouble this attempt was, and not even successful. So unless somebody lives in pittsburgh and would be willing to work out an arrangement to either get the one it has working or a 730, then I have less than 0 interest attempting anything that isn't plug and play with known good components. I have no idea why my swap failed, I know the problem, but without the cause its useless information. My injectors pulse way to fast, and cut out the moment it starts to catch and run. Like I said, atm, I just want it to freaking run again.

              And thanks for the answer, also fyi, someone is working on cracking obd 1.5 fwiw, and I also meant to ask, whether or not the SES light can be disabled with tuning?
              But you would still be swapping a harness and PCM for your ECM. You are making a lateral move if you want the car to run. If you want plug and play, you could always get a harness and ECM from a 90-92 and put it in your early car (also the MAP etc)..
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              • #8
                Could you elaborate on the lateral move and the etc. please?
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                • #9
                  You said you didn't want to re-wire again. There will be a lot of re-wiring to get the 4th gen PCM in a 3rd gen body, much more than just using the '7730. The '7730 runs on a MAP not MAF.
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                  • #10
                    I said I didn't want to rewire an ECU, the non ecu crap I don't mind rewiring, there is no rewiring for the engine side of things. I am getting a whole wiring harness, and ECU from a 93, other than a few wires going to misc. bs in the dash, it will be plug and play no different than replacing a wiring harness and ECU on a 4th gen car. Though atm, this just took a back burner cause my gd corsica bit the bullet out of nowhere. God I hate POs.
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