dasmoover

Hello guys, I've got my stock 280z running- for a bit. I bought the car in this condition. 1977 OEM Stock everything 35k miles. Car runs extremely smooth when turning her on while cold. Car will run for a good 15-20 mins idling without driver intervention. Randomly the relay above the EFI clicks repeatedly - as this happens the RPMs drop from ~900 down to about ~500 and sometimes stalls out if the clicking does not stop. As soon as the clicking stops the RPMs shoot right back up to ~900. After it gets close to operating temperature there is more chance of hesitation or backfiring when trying to give it gas, other times when the relay clicks any attempt to give it gas stalls the car instantly. I have cleaned all the electrical connections thermotime switch and CTS especially. What direction should I head in? It seems the EFI system works until it gets warm. However, the clicking will happen regardless of temperature making it seem like a loose ground or something. Thing is it will happen with the car idling no one inside and then correct itself. Any input would be greatly appreciated!

Not aggravated just trying to be as concise as possible. I appreciate all your input, truly. Hopefully someone else has some valuable knowledge on the TIU wiring. Thanks again.

To clarify I am testing the transistor ignition unit at the passenger panel as suggested by Steve. My wiring is 100% correct as far as ignition system goes. The ballast and coil are wired properly. I disconnected the blue wire from the Transistor Ignition Unit and tested for voltage with key off and on. At off I get 12v to it from the battery as suggested is correct. With the ignition on, wire still disconnected from TIU I get no power. I believe this wire is shorted somewhere. I AM NOT TALKING ABOUT MEASUREMENTS UNDER THE HOOD. I am doing these measurements at the blue wire at the TIU. I repeat, my wiring setup is OEM Stock and have confirmed it is correct tracing the wires. This is NOT at the ballast, coil, etc. UNDER THE PASSENGER KICK PANEL with the TIU. No disrespect, I appreciate all input, thank you Zed Head. I just want to provide the correct information to expedite the car's revival!

At the ignition module passenger side as Steve suggested.

I did a test with the multi-meter. I get 12v with ignition off. With ignition on I get absolutely no voltage on the blue wire. I'm holding off on the HEI module until I figure out why I lose voltage. Any thoughts? I've overlooked all wires that are exposed outside of the main harness. No loose connections/grounds there. I'm worried it may be somewhere inside the harness. Perhaps fusible link on battery terminals?

I can confirm it is the stock distributor. The car ran before the live spark damage. I'm set on the idea that the TIU was damaged when the sparks flew. This could explain why I do not hear the door buzzer when I turn the ignition on. The fuse is fine, hazards work. Turn signals do not light up on the dash.

That's what I had initially thought. I am going to replace TIU with HEI module. StevebJ, what other tests can you recommend or items to look at? Thanks.

Just to be sure, you guys are talking about the little black box next to the distributor? Here's a picture without the cap, looks golden. Or are you guys discussing the TIU like I am talking about up in the passenger kick side? I only get 8v with ignition on, have not tested while cranking yet. Will do those tests as soon as I can confirm that I'm testing with the TIU. Thanks.

I've confirmed my wiring is correct as far as the ballast resistor, coil, and transistor ignition unit go. I'm going to buy the HEI module and wire that in. I imagine since the battery is directly connected to the TIU it may have caught that spark and may have been rendered damage. Here are photos detailing the mystery wire, ballast and coil. Any inspiration beside TIU? Maybe fusible links by battery? Thanks. I am getting 8volts with ignition on so it seems circuit carrying the high tension power is not available. Which is the high tension wire so I can fully trace and test? This is why I imagine the TIU is damaged.

Photos were taken the day of the post weeks after the incident. I think the first line of business it to get the voltage readings in different states and then isolate that extra blue wire. From there if that doesn't solve it, I'm going to have to get to know my meter quite well.

Excellent that's what I shall do tomorrow. The kit I ordered only came with the 4. That may be suspect. I have a meter. I get voltage on the negative and positive coil. I will take all the photos tomorrow. I had the battery terminals on correct the first time. They only extend so far. Thank you Zed Head,

Let me be as concise as possible. A few weeks ago I placed a battery from my 84 300zx because the one it had was dead, before turning the engine I flicked on the engine bay light and live sparks flew from the battery down to the fusible link and effectively melting it. It also sent the electric charge down to the alternator and it caused some smoke. Since then I have replaced all 4 fusible links and can confirm voltage on all 4. I'm still concerned about that missing connection though. I will take more pictures tomorrow that accurately describes the the wiring setup that the car has now. I can confirm I am not getting SPARK from the ignition coil to the distributor. I am getting continuity on both pos and neg on the coil.

The car has been wired to the specifications of the diagram I attached to my previous post. There is the negative going to the ballast. I have a black wire that jumps from the condenser to the BCDD as noted in pictures of first post. (see black wire with bullet going straight to condenser)

I've checked each wire going to the ballast they all return to the harness. Here is a correct 1977 diagram. I still have an extra blue wire that goes back into the harness. It has newer blue electrical tape indicating it has been messed with. Any leads as to what this wire could be for...

So it attached to the negative terminal on the ignition coil? That's what it's looking like. I have the correct wiring on my ballast. Just missing the second one going to my negative end on the coil.

Tach has no response. This sounds like it would be the short in my ignition system. I will take a look at the diagram and see where it is supposed to connect and attach it tonight. Thank you!

I have done the starter fluid test to no avail and the car is basically bone stock.

Thank you so much for the test ideas! Do you mind sending a link to the correct HEI module? Worth a test for the price. Zed Head: I will take more photos tomorrow. The blue wire comes from the main wire harness. I checked a spark plug for spark, no good. The blue wire could be responsible for failure switching over to EFI after cold start valve bypass. Thank you! I know i'm not getting spark at the moment. I will be able to conduct all the tests tomorrow.

I don't want to continue shotgunning new parts in. I want to find the source of all my symptoms. The brake light comes on when the ignition switch is set to ON but still no turn signals. How do you test resistance for these things? - What is the resistance from the postive terminal of the coil to negative terminal? What is the resistance from the center post of the coil to the negative terminal?

I will post back with more photos. The plastic cap on the coil spark wire is covered with golden dust. There is no burning, just very small metal shards, very clean and shiny otherwise. Thank you for the tips. The positive terminal read 8V on the coil with ignition on. I have yet to test while cranking.

New to the world of Datsun/Nissan. I'm working on a 1977 280Z. Currently having an issue with spark. No spark to the spark plugs. I have read through the FSM/EFI Bible. The coil has been replaced (then swapped back to stock unit only 35k miles), ECU has been replaced, battery has been replaced. Fusable links have been replaced and all get spark on both ends. Headlights work. Checked fuse panel under passenger kick - none blown. Cleaned all electrical connections and grounds with C&C. I am getting spark from the ballast resistor and to the + and - on the coil with ignition on. Have not tested while cranking. Engine cranks no problem, fuel gets to the injectors, engine won't start. Symptoms: With ignition on door buzzer does not sound. Hazards and turn signals DO NOT WORK. RPM Gauge does not move at all when attempting to crank. Back-Story: Bought the car with 35k miles. Ran only off cold start then died when kicking over to EFI. Towed it home, started it a few times, battery had died. The original battery had an acid leak and gunked up the terminals. Cleaned the terminals up a bit. In the mean-time I put a battery in from my 84 300zx. Attached the terminals. I flicked on the engine bay light and my fusable links sparked and sparked the wire going to the condenser on ALT. I did not attempt to turn over the car. I removed the terminals and the battery immediately. Bought a new one and put it in. All lights work, but now the hazards/turn signals/spark/door buzzer is gone. Replaced all fusable links and confirmed voltage on both sides. Could I have also blown my Transistor Ignition Unit or my Ignition Module? Thanks for any input, it's been about a month and I've only narrowed down my possibilities. It thought I damaged my ECU, now i'm thinking either one of those two components are failing OR there is a short somewhere near the battery terminals or inside the harness itself. All the fuses are fine and the relays all click for fuel pump/injectors. Lead ignition wire is connected. I have identified and cleaned all the electrical connections on both sides of the front end, nothing obvious is loose or shorted. There is ONE blue "L" wire disconnected near my ignition coil. Attached are some photos. Any input would be appreciated.