Announcement

Collapse
No announcement yet.

3,000 RPM Jolt - injector rewire for NA2T

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • 3,000 RPM Jolt - injector rewire for NA2T

    I have had this problem ever since i went turbo. Almost in every gear (not gear specific) i get a big jolt when i cross 3,000 rpm. This especially sucks when driving at highway speeds, ~70 mph is right around that range and that's the typical speed i travel.

    It's especially bad in low gears/speed. It feels like i let off the gas for a milisecond. Its really bothersom.

    89 NA Engine
    Recall wiring
    84 T Injectors, ECU, Turbo

    I am almost positive this is related to duty cycle changes in the injectors.

    SO, a while back, i attempted to revert the wiring job on the injectors. I had about 6 failed attempts. The car would idle rough, and drive even worse. I tried several combinations. 89NA Wiring, 84T Wiring etc etc, each time i would try something different. I soldered every contact, had every wire clean and neat.

    I am looking to fix this retarded problem once and for all. It seems no one ever has any good insight on injector wiring across NA2T platforms.

    I have an 89NA injector harness, but it's being driven across an 84T ECU. There are differences in color and although i don't recall at the configurations at the moment but i have them in my FSMs.

  • #2
    40 views and no insight

    Comment


    • #3
      why did u rewire the injectors? There's no need too.
      Are you sure u didnt touch the timing?
      1986 Current build
      HX35/40 60mm wheel,480cc injectors,nistune, spearco 2-221,6 puck,walbro fp,solid cross and diff,jason motor mounts,poly everywhere else.

      Comment


      • #4
        Define Jolt. I think I have an idea of what you mean but I would like a bit more clarification as to what exactly you are feeling at 3k rpm.

        Does it happen on acceleration and deceleration?

        Do you see any change in RPM as you are passing 3k? up or down jumps?
        Just stand back and throw money.
        Performance costs money.
        Reliable performance costs more.

        Comment


        • #5
          I rewired the injectors because i was advised to do so, that's why.

          It's never when im slowing down, usually only feels rough when im accelerating slowly, when its fast its usually not as bad, but still does it.

          it feels like its missfiring, at exactly 3k rpm....never below, never above (by much)

          Its a hiccup....

          Comment


          • #6
            bump

            Comment


            • #7
              Someone else with more ecu tuning experience than myself should hop on this, BUT!

              *With what I have learned so far, and seeing what a stock timing map does in that area...it is too much timing advance the ecu is using.

              Try to offset the problem by retarding the base timing at the distributor some, then report back.
              I am here to help...

              Comment


              • #8
                Well, you see...the timing issue is a big one. I can't get 20 degrees.

                Any less than i'm running now and it feels like it has no power, i mean...pretty much absolutly no torque until 4k rpm and WOT...worse than my NA.

                I think im currently running 25-30 degrees. It's jumpy when im looking at it with my timing light. If i pop the dist a tooth over, its on the other side of the spectrum, 10-15 degrees but no 20. This blows.

                It's done this 3k bump ever since my NA2T conversion...

                I havn't fiddled with my ECU, and i've swapped with another 84T ecu and it still does it

                Comment


                • #9
                  Well, You know where I stand with my 3 degree base timing "bobble".(I edited the response in that other Timing thread you had)


                  Have you tried replacing the distributor yet and tried to re-time the engine with the replacement distributor?

                  Knowing what the ecu does with the timing at that 3000rpm threshold under no load and light loads...the answer obviously points at the Base timing issues you are having.... in my honest opinion.
                  Dan
                  I am here to help...

                  Comment


                  • #10
                    Sounds like it COULD be from the advanced timing... I would give it a shot.

                    If the engine timing is off that much, you could always easily compensate for it in the programming by changing all the timing maps.

                    Comment


                    • #11
                      JustinCase wrote: I rewired the injectors because i was advised to do so, that's why.

                      It's never when im slowing down, usually only feels rough when im accelerating slowly, when its fast its usually not as bad, but still does it.

                      it feels like its missfiring, at exactly 3k rpm....never below, never above (by much)

                      Its a hiccup....
                      Can you reproduce this effect when the car is not moving? That is, hood up?

                      If so, I would use a timing light to watch the timing and then rev the engine up and down around 3000 rpm. Look for large jumps in the timing as the car 'burps' around 3000 rpm.

                      I assume that you have changed the timing belt? Counted all the teeth and made sure that it is exactly installed?
                      Try not to be a Yahoo

                      Comment


                      • #12
                        [quote]crowbar wrote:
                        Originally posted by JustinCase
                        I rewired the injectors because i was advised to do so, that's why.

                        It's never when im slowing down, usually only feels rough when im accelerating slowly, when its fast its usually not as bad, but still does it.

                        it feels like its missfiring, at exactly 3k rpm....never below, never above (by much)

                        Its a hiccup....
                        Can you reproduce this effect when the car is not moving? That is, hood up?

                        If so, I would use a timing light to watch the timing and then rev the engine up and down around 3000 rpm. Look for large jumps in the timing as the car 'burps' around 3000 rpm.

                        I assume that you have changed the timing belt? Counted all the teeth and made sure that it is exactly installed?
                        :roll:
                        (You know the saying....)
                        *"You're a day late and a dollar short"!
                        ~This topic has been ongoing through a couple of threads now.
                        I am here to help...

                        Comment


                        • #13
                          Yeah its a very common saying. Care to possibly explain what you think it means?
                          Try not to be a Yahoo

                          Comment


                          • #14
                            I am a bit of a Johnny-come-lately to this issue, but I'm going to have to agree with crowbar..

                            The first thing I thought when I heard the lack of power, and not being able to get it to run the right timing was incorrect timing belt install.
                            It may not be a Z, but it's still got a turbo...

                            Comment


                            • #15
                              considering the stock timing adjustment has to allow for 15 and 20 degrees, if you can't get in that range then something is wrong with the only thing that controls the distributor.... the timing belt

                              Comment

                              Working...
                              X