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Hello everyone I had a question about voltage. I am a newbie when it comes to wiring and electrical but I did my research and read the forums. I have a 1977 280z and it looks like someone’s been in there trying to figure out the issue. Missing bolts etc. anyways with my multimeter I tested the coil and the resistor and voltage. the voltage was off.. well there was none with the key on the on position, testing on the first terminal on the resistor. so this is what I checked, I went to the battery and checked the cables those are good, car turns over. I looked at the wiring diagram and found the black and white wire that leads to the ignition relay. That wire read at -12.45 volts. As if I I had my wires crossed on my volt meter. Then I searched and found the red and white wire that leads to the battery. And again same thing that wire read -12.45.. I went back to the battery terminals and tested there and that was +12.45. Sooo my question is why is it reading as negative in the wires? Is this normal? Andy ideas as to why the black and white wire that goes to the resistor is getting no power..

Hey all, I did the transistor ignition unit upgrade as described here: Given this though, I have had some problems after doing it. Given that I have a '78 I don't seem to have a resistor below the ignition coil but I think I wired the HEI module in correctly. I think it is correct since it ran for over 6 months, and the last 7 weeks of that was the car being driven daily. On the 7th week though, problems began. The car became slowly harder to start taking longer and longer to crank until it eventually stopped firing all together. I have checked and the car has fuel and air, just no spark. Seeing this, I replaced the HEI. After replacing the HEI the car stumbled as if it would fire and then resumed cranking with no spark. So, have I installed the HEI correctly for a '78 280z? If so, what else could be killing HEI modules when I replace them? I have attached pictures of my module installed:

Hello and thank you taking a look at my issue. I've just finished turbocharging my NA 1978 and have been running into many issues. Firstly, the car will crank for days but never starts, I've narrowed it down now to spark. I have disconnected the transistor ignition unit as it has an e12-80 module and distributor from a 1980 zx, with a new cap, rotor, and aftermarket ignition coil. Verified rotor is spinning. On the ignition module I have C going to Negative post on coil and B going to Positive. I have the Blue/Black wire & Blue wire connected to Negative on the coil, and Black/White connected to Positive. (There's a skinny white/black wire that I have no clue what to do with, can't find anything on it). I also have a wire connected to a post the distributor going to chassis ground (that wire got a little warm while trying to start the car, strange, disconnected and still no start.) The coil is getting 12~VDC at both posts with key at ON, and 0.00 with key at OFF. Any leads would be greatly appreciated, just want to drive this thing again 😔

Hi I have a 78 280Z that wont run. 2 Owner California car, very clean. I had it running when i bought it, but it always started rough, backfiring and sputtering. After replacing some hoses, I drove it about a mile and it started running very rough and had a major loss of power. I have checked for spark and fuel pressure (you can hear the pump running, too). It will crank and not even backfire or fire at all. Compression is also good. I do question the wiring because the pins on the ECU/ computer and the leads on the fuel injectors do not correspond with a wiring diagram I have. Faulty crank sensor? I have replaced all the easy ignition stuff- Wires plugs cap rotor. Really at a loss, ive never worked on anything with EFI and no OBDII before. Thanks

alrighty, so i recently bought a 73 240z project car and i am stuck. the problem started with no fuel, but the fuel pump was bad, so i swapped in a new one and other than the lines being clogged, that issue is resolved. then i checked to see if i was getting spark, and i was not. so i replaced the distributor cap, points, rotor (the guy that spins in the distributor), coil, spark plugs, and plug wires (installed correctly checked twice). still no spark. so i started to forum search to try to diagnose the problem. ==to check if i got spark or not i removed the plug wire from the #1 spark plug and put it close to the block, head, and spark lug to see if it arced. -I checked to see if the coil was getting power by removing the ground wire, attaching a new one, and seeing if there was spark whever i touched it to brae metal. -hard lined positive end of the coil to the positive terminal on the battery, hard lined a new ground to the negative side of the terminal, checked to see if i got spark, nope. there are a few things attached to the coil and distributor that i am not really sure if i need them/ what they attach to, and they might be what is causing the no spark. here is the coil 1. is a coil condenser? i think. this came with the car and the wire was borken so i spliced it back together 2. BY wire, is a wire that goes to, i think, the ignition. 3. is possibly a ground but i have no idea where it grounds out 4. i have no idea what relay it is 5. i have no idea what this is here is the distributor here is a condenser that i replaced, and there is a prong sitting at teh top of it that apparently goes to the coil negative side, but where would i connect it.

I was driving around 60mph, dropped it into 4th to pass some traffic then soon after I noticed the gauges all stopped working and realized the engine was off. Once i got to a stop I tried to start it, it cranked but wouldn't turn. The lights for the gauges work fine but the needles on them are all pointing south now like the way they would be when the car gets shut off. My alarm and parking lights also all work fine. The car ran fine prior to this happening. I'm thinking there is a direct correlation to the gauges not working and the engine not turning over, something electrical, blown fuse or relay? Has anyone else had this type of problem or know what the problem may be? Any help will be appreciated. Thanks. edit: It's a 77 280z with a stock engine.

Hello all, I've been tinkering on my Z for awhile and I'm having a hard time getting it started. I had a stock 240 dizzy with the pertronix set-up and then added dual webers. It ran wonderfully but I decided that I needed a distributor without the vacuum advance. So I ordered a unilite, installed it, and now I'm getting nothing. I've checked for spark at the plugs and the coil, no spark at either of them. I've checked the module on the unilite and I'm getiing 11.8V with ignition on and 0.8V with an interuption in the LED. (believe this to be good) I've double checked my wiring to no avail and even tried a few different configurations I've seen on previous posts. I've got 12V at the coil with the ign on but As of the moment, the only action I get from the ignition is a spark on my tester when I turn the key from "run" to "acc"...just a short burst from the coil wire So I am very puzzled as to what the problem is, I've got a few hunches but I want to get some positive re-enforcement or some new ideas becuase my head hurts!! Thanks ahead of time! :nervous: Shane