Z randomly starts to sputter and stall out

  • #1

    Z randomly starts to sputter and stall out

    I just got my z back on the road after waiting 7 months for my engine to be rebuilt. Im trying to put the 1000 miles on it before taking it to the dyno to tune but the car isnt behaving to break it in. Not sure if its the tune or something else.

    When I was driving and just barely maintaining throttle to drive at low speeds seems when this happens most. It will start to sputter and I got to keep pumping the gas to keep it running, as soon as I stop it stalls out and it doesnt want to restart. I have to pull off let it sit then it will start up again.

    It doesnt happen all the time, the first 2 drives I took had no problems. Now it was 35 degrees out when this happened so im not sure if the cold temp is effecting it.

    Also not sure if timing is the issue. I know the car is supposed to be 15 btdc at 700rpm. However I cant get my idle to 700 rpm without stalling or even start. Its set at 15btdc at about 1000rpm. Also I have to give it gas while starting to get it to start when cold but not when at operating temp.

    Some info on the cars setup.

    88 turbo ecu with nistue
    Ngk bcpr7es-11 gapped at .25 with ngk wire
    Z32 maf
    Benz injectors with resistors
    8.5:1 bcr pistons with eagle rods
    Vg33 heads with ferrera racing valves
    Isky mega cam regrind 280 intake 270 exhaust
    Schneider double valve springs 110lbs seat pressure
    Walbro 255lph fuel pump
    Intake spacer
    Turbo is t3 t4 hybrid
    44mm mm external wastegate
    Dxd stage 4 clutch with fidenza alluminum fly wheel
    Uses 93 octane gas

    The car was a 88 na that I converted to turbo. I have the wire harness altered to us the correct o2 sensor and converted the ficd idle control to the turbo models idle air control. Egr has been removed

    Im not sure if the idle control be be the issue. It gets really hot to touch but im not sure how to test it.

    It was partially tunned on the dyno. It had a base tune layed out that had it around 410whp but a vacuum line popped off the fpr on a dyno run and blew the tip off off the no1 spark plug making the tip gouge the cylinder wall which is why I had to rebuild the motor. We never got to do fine tunning of the ecu.

    Its also wierd in that the car will idle fine sitting in place but fore some reason if I put it in neutral while costing down hills the car will stall out.


    Sorry for the long post but im stumped on this.
    The saing goes you save the best for last which is why the letter Z was chosen as the last letter of the alphabet. It is also why it was chosen to represent the best car of the 80's.

    Respect the Z
  • #2
    A little more info. The sputter feels like a limp mode. It won't letthe car rev above like 2500-3500 rpm approximately. It hits that stops drops down then revs up to that again bouncing off it like a 2 step while I keep the gas floored but if I get off the gas it shuts off
    The saing goes you save the best for last which is why the letter Z was chosen as the last letter of the alphabet. It is also why it was chosen to represent the best car of the 80's.

    Respect the Z
  • #3
    Anybody?
    The saing goes you save the best for last which is why the letter Z was chosen as the last letter of the alphabet. It is also why it was chosen to represent the best car of the 80's.

    Respect the Z
  • #4
    Troubleshooting this with a stock setup would be the typical:
    • vac leak
    • fuel pressure
    • chts
    • O2
    • AAC

    But since you're running a custom recipe/setup, i'm not sure how much of that would still apply.

    I didn't see it on your list but, do you have a wideband that you could monitor logs from and use to help you narrow down what's going on?


    84 AE/Shiro #683/Shiro #820/84 Turbo
  • #5
    I have an innovate lc1. I need to recalibrate it though and weather hasnt been cooperating with that

    I feel it has something to do with the aac but im not sure how to troubleshoot it
    The saing goes you save the best for last which is why the letter Z was chosen as the last letter of the alphabet. It is also why it was chosen to represent the best car of the 80's.

    Respect the Z