Another no spark/injector pulse nightmare thread.

  • #1

    Another no spark/injector pulse nightmare thread.

    Car info: 1986 na2t swapped in june of 2013 with all the parts being from an 85, minus the wiring harness. Also did the RSB-07 and PWR-2 at the same time. Up until recently I've had no problems.

    Story time! Okay so about a month ago I was driving home from the auto parts store and the z started running really crappy and had multiple misfires. Then the car completely died upon pulling in the driveway, tried to restart nothing. let it sit for a few hours and tried again, nothing. After doing some research I had an hunch it was the cas. I put the motor at tdc and pulled the dizzy out and spun it to listen to see if i could hear the injectors pulse, nothing. I also checked the mechanical timing and its where it should be.

    I happened to have three extra cas, two rsb-07's and a rsb-06. Also have three extra PWR-2's. After trying a combination of all of them plus different trigger wheels, still not getting spark or injector pulse. Maybe they were all bad seeing how I pulled them from the junkyard? Keep in mind that I've been running a rsb-07 and pwr-2 for over a year now so I dont thing its the wires that I swapped for the pwr-2. I also had an extra good coil laying around, still didn't help.

    Okay time to dig deeper. And after I read up on the FSM I check for resistance for ground and voltage where the fsm instructed me to in the cas harness and both resistance and voltage were what they should be. Although I could not check pin 17 & 8 as an insulation check because the probes on my multimeter are too big. I also couldn't check pin 17 & 8 as a continuity check as I dont have a jumper wire.

    So not being able to check 17 & 8, I just decided to try my luck and buy a new cas from Acadiana sports car orphanage (ASCO) on 08-18-14.
    (Got here super quick, thanks guys!) Any guess on what happens next? As my luck would have it, still no spark or injector pulse! After a few hours of blowing off some steam I remembered that I still have my old NA spec ecu. I was really hoping that it was my current ecu that is bad so I swapped in the old ecu with high hopes. But alas, STILL NO SPARK OR INJECTOR PULSE!

    Could it be possible that both of my ecu's are bad? Although that seems unlikely as the car ran off the old ecu fine prior to the na2t swap.
    So I'm thinking its either the ecu or the engine wiring harness. Although I'm leaning towards the harness.
    Sorry if the story was a little hard to read.
    Any input would be greatly appreciated! Not sure what to do from here…
  • #2
    It sounds like you're still able to crank the engine over, right? If so, do all other items work? … headlights, radio, hazards, etc. If yes, meaning they all work, check the main ignition fuse. It's top center in the foot well panel and rated at 15 amps. If that's blown you have a short and are not getting +12v to your coil positive. Replace the fuse, disconnect the 2 wires to your coil (not the high tension one), turn the ignition to the point where the dash warning lights all illuminate and then check to see if you have +12v on either wire that you disconnected from the coil. If not, you have a short … and you just blew your new fuse. You can then shut down and confirm this by taking an ohm meter and testing between either coil wire and ground. The short will show up as very low resistance (less than 1 ohm).
    If no fuse has blown, and you show +12v on the ignition coil wires, I would then check the infrared diodes that are in the distributor operating with the CAS. They might stand for a cleaning. If you can swap with a known good distributor and the car starts it would confirm this.
  • #3
    Have you checked fuel circuit components? No spark will occur if the ecu doesn't see that fuel is being supplied to the engine. Fuel pump turning on? Fusible like good? Fuse good? You may have a green relay called the safety relay by the fsm that can cause this as well as the Orange 3 pin relay that's essentially a fuel pump relay under the hood.
  • #4
    All of the lights work. No blown fuses and I'm getting 12 volts from wires that go the coil. What/where are these infrared diodes you're talking about? I've never heard of them before. And as far as the fuel pump goes, I can hear it prime up to the injectors and fpr.
  • #5
    he's talking about the light sensor inside the CAS' but that's irrelevant if you're swapping between what, 3 or 4? start tracing powers and grounds to figure out who's doing what!!
    Damn dirty angels....these cars!

    Current Daily Driver - 86 Turbo.
    Under the cover - THE BANANA… that needs to be re-energized.
    sigpic
  • #6
    It might be something as simple as the wire plug connectors from the CAS wire. Maybe not from the distributor's end, but on the connector socket inside the engine bay. Over time flexing, heating, plugging and unplugging can make connections go south.