Villeman Posted April 2, 2020 Share Posted April 2, 2020 (edited) Hello Guys, I stumbled upon a problem getting my car out of hibernation. The car: All stock unmolested 280z 2+2 CALIFORNIA VERSION from 9/75 -> 76 Model. Everything still in place, CAT,EGR,Vaccum system etc. I drove maybe 15 km and the engine stopped INSTANTLY. No stumbling nothing --> Indicates an ignition problem since car ran after a 15min break, only to die again 3 min later. Same happened after towing it home. Sadly I did not monitor the tach so no idea if it dropped suddenly Observations: Fuel Pump was very quiet, ran today and was a lot louder. --> would indicate fuel pump issues Metered the coil+ballast today: 2.8Ohms , FSM says change over 1 (correction, FMS says change if COMBINED VALUE is over 2) ….BUT the coil itself read 1,5 Ohm, so I assume it was changes from the stock 0,6 Ohm at some point (Dan? ) One weird part, messed around with the wiring under the steering wheel (thought about ignition key issues) and I shut down, but I could never repeat this issue. My questions now: Which coil to replace with (just to be sure), because Pertronix etc are all 1,5 or 3 Ohm. Any idea how to check the fuel pump before changing it? (I had issues with a LOT of rust, basically the pump had to chew through a pound of rust from the tank so I would at least not be surprised ) Any other ideas? ICM is hard to test, currently looking for a GM HEI Module to bypass. Did fry the ICM with a hairdryer on hot though, no issues thanks in advance, Richard Edited April 3, 2020 by Villeman FSM quoted wrong Quote Link to comment Share on other sites More sharing options...
NewZed Posted April 2, 2020 Share Posted April 2, 2020 So it runs now, or it hasn't started since it died? Can't tell if "ran" means just the fuel pump or the engine. The ballast has resistance so coil + ballast would be the two resistances combined. The coil reading is high though. Just get a stock aftermarket coil from Autozone. Most fo the name brand coils are plain old coils with colored labels. Check the resistance and wiring in the distributor also. Sometimes the breaker plate moving can short the wires to the pickup coil. Probably a good time to just go through all of the electrical specs and adjustments, like the air gap. Sudden dying can be the ECU also. That's a hard one to diagnose. Quote Link to comment Share on other sites More sharing options...
Villeman Posted April 3, 2020 Author Share Posted April 3, 2020 (edited) It runs perfectly after 20 minutes. What I observed: It now sounds more "powerful" , maybe better spark/change of spark? (I disassembled the resistor for measuring properly) We drove it again and it cut out from running perfectly. Tach dropped to zero immediately. Cranking afterwards moved the tach though. We brought another spark plug along, directly after the engine dying we checked and had spark (but that time you could restart it after 30 seconds, not like last time where it took 15 minutes). One funny thing, it cut out again while driving but then I ran over a speed bump and it ran again……. O_o What I will do now, get a HEI modul, coil (if I see it right, around 0,5 Ohm and NOT the 1,5 or 3 Ohm ones) and clean the ignition lock. One thing, the ignition lock is quite word, you can pull out the key while running and it continues to run. Could this cause those problems? Edited April 3, 2020 by Villeman Quote Link to comment Share on other sites More sharing options...
jhm Posted April 3, 2020 Share Posted April 3, 2020 Sounds like a loose connection somewhere in the ignition circuitry; judging from your statement about driving over a speed bump. WRT your question on the ignition switch/lock: no, I don't believe that would contribute to your issue. Once the ignition switch is moved to a particular position, those connections are completed and it doesn't matter whether the key is in the switch or not. My key is very worn, as well, and I can remove it from the switch anytime without any affect. Quote Link to comment Share on other sites More sharing options...
NewZed Posted April 3, 2020 Share Posted April 3, 2020 (edited) 6 hours ago, Villeman said: One funny thing, it cut out again while driving but then I ran over a speed bump and it ran again……. O_o People have had problems with broken solder joints in the ECU that were fixed temporarily by tapping or banging on the ECU with their hand or foot. Easy to try, when it cuts out reach down and start banging and see if it restarts. Opening and closing the door or the hood might have the same effect, explaining why it restarts for no apparent reason. If that has an effect at least you'll know what to look at. Apparently the solder joints at the plug connection are the bad ones. Some people have success reflowing them all. The loose key is very common. Almost everybody can pull the key out of the switch at any position. That's not an electrical problem though. Edited April 3, 2020 by NewZed Quote Link to comment Share on other sites More sharing options...
Villeman Posted April 4, 2020 Author Share Posted April 4, 2020 (edited) Update time: managed to get a 4 terminal HEI Module in Germany and threw it in yesterday. I followed Eurodats description on classiczcar and put it in place in the passenger footwell. Car runs really! good now, no issues with engine dying anymore (more testing to come). The only issue was a hot-start problem, car wouldnt run after shutting it down hot. the weird thing, we pushed it back 2 meters and it immediately started again (was cranking over before but quite unwillingly). But I did fill up with E5 (presumed to provoke vapor lock) Battery was low-ish Temp switch sensor has a nearly ripped cable -> so more things to fix I don´t think those two things are connected. Thanks for your help everybody! Edited April 4, 2020 by Villeman Quote Link to comment Share on other sites More sharing options...
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