Announcement

Collapse
No announcement yet.

Fuel Injector Wire Harness

Collapse
X
Collapse
  • Page of 1
  • Filter
  • Time
  • Show
Clear All
new posts
Previous Next
  • #1

    Fuel Injector Wire Harness

    One of our 93 Z's has a dead injector in #6 cylinder. Black, sooty plug, no pulse felt when engine is running. Substituted a new injector and it did not work either. Fuses are good as all other cylinders are operating.

    It appears that we have a problem in the control circuit of the injector. Anyone else have this problem?

    Thanks,

    Tom
    Tags: None
  • #2
    If one injector is not firing, and the other three are in that bank, the wiring problem would have to be in the pigtail for that specific injector. In the 93's, the +12V power is supplied to multiple injectors from the same source, and the PCM has a single wire to ground all 4 injectors on a bank, since its "batch fire".
    Fred

    381ci all-forged stroker - 10.8:1 - CNC LT4 heads/intake - CC solid roller - MoTeC engine management - 8 LS1 coils - 58mm TB - 78# injectors - 300-shot dry nitrous - TH400 - Gear Vendor O/D - Strange 12-bolt - 4.11's - AS&M headers - duals - Corbeau seat - AutoMeter gauges - roll bar - Spohn suspension - QA1 shocks - a few other odds 'n ends. 800HP/800lb-ft at the flywheel, on a 300-shot. 11.5 @ 117MPH straight motor

    Comment

    • #3
      Just checked the voltage at the pigtail

      I just checked voltage at the pigtail and had 12 volts on both sides! I'll go check it again!

      Comment

      • #4
        I think we finally got it!

        First of all, thanks to all who offered suggestions and advice.

        The 93 Z just rolled over 180k miles!

        Turns out that the problem of intermittent missfire was actually many things happening at once. Fuel pump, injector wire harness, coil wire and O2 sensors!!!

        We solved the wire harness problem by moving the connector from #6 to #8 and now both injectors are working so there is apparently a break in the #6 harness that we cured, momentarily, by reorienting the harness. In this case, thank goodness for "batchfire".

        Fuel pressure was down in the low 30's when I replaced the pump.

        Big arcs that could be heard and seen in daylight helped locate the coil wire problem so a big MSD wire sits there now and all is quiet.

        O2 sensors had neared the end of life so we replaced them as a matter of course.

        With the #6 injector not working, the O2 was seeing a rich condition and thus forced the other injectors to a shorter pulse, leaning out the engine. The plugs showed the effects!

        Now, all of this just makes me appreciate my 69 Z-28 all the more!!!!

        Again, thanks to all

        Tom and Thomas who just got back from Iraq!

        Comment

        Previous Next
        Working...
        X