S30Grit

Thanks all, I don't mind the looks of them if I used it as an accent color, but I prob won't go through the hassle of putting them back on.. Seems serviceability wasn't in mind when they were installed 😕

I was in the process of removing my fenders to clean out the dirt underneath and check for rust. Then I realized these side skirt things I have are riveted on, smh.. Guess the only way would be to drill the ~20 rivets out through the body, just curious if anyone else has this piece installed? Maybe it was a dealership option or a previous owner did it, but what a pain..

A final update on this topic: After chasing down random wiring issues and corrosion, I found the core of the starting issue. It was ironically simple: the aftermarket ignition relay was not wired correctly. If anyone else finds this thread in the future, the problem/solution is described below: The previous owner purchased this part (again a Zcardepot part), https://zcardepot.com/products/starter-relay-upgrade-replacement-280z# It looks like it comes pre-wired from zcardepot but I can't confirm that since I didn't order/install it. If it was pre-wired then it's not plug and play, at least for the way my car is wired (78 280z) and requires swapping the two blue wires. Anyways, as many probably know, the "ignition relay" is basically two relays in one: one relay to power ACC (accessories) circuit and one relay for IG (EFI/fuel pump/etc). In my case, the output of the relays was swapped. Meaning that my EFI/Fuel Pump/etc were getting power when the ignition switch was outputting +12v for ACC, which is when the key is in ACC or ON position. But as many know, with most cars, when you turn the key to "START", the ignition switch does NOT output to the ACC circuit ?‍♂️, explaining most of my issues... Therefore, the solution was to simply to swap the two output wires on ignition relay harness (the two blue wires in the harness). For reference, tests on page EF-27 from the FSM will help identify the problem (you'll find Fuel Pump relays aren't getting power when ignition is in START position). Essentially the two ignition relays should be wired as followed: • IG relay: WB is the relay "output". WR is constant +12v. BW is relay on/off, connected to IG of ignition switch • ACC relay: LW is the relay "output". WR is constant +12v. LR is relay on/off, connected to ACC or ignition switch Thanks again for everyone's help. A lot of terminals a definitely a lot cleaner than before, ultimately the FSM wiring diagrams helped me backtrack through the wiring issues with the starter unplugged..

That does look ideal and clean. I ended up using those large fuses commonly used for amplifier installs. Easy to connect up, relatively good weather seal...

yeah, inspecting the connectors to the links, there's tons of corrosion. And the wire ends/crimps are barely hanging on. I'd rather just swap the links out. I'll cut the wire back a little bit to see the condition of the wires. I'll be putting two 40 amp in-line fuses in place of them. I see the fuses vs fusible links has been a hotly debated item, but I haven't read any reports of cars starting on fire, so I'll go with the easier option

Ahh, thanks. Definitely bookmarking that one. I already bought an inline fuse on amazon that will hopefully do the trick

Well, I thought I was fixing a lot of wiring issues and removing a few shorts, but now I can't get her started at all. I went back and did the FSM ECU-removed tests and seems I don't have power from the EFI relay anymore. I'll hopefully track this problem down soon. However, looking at some other wires in the engine bay, I found these guys (pic below) but couldn't seem to track them down in the FSM. Either way, I'd really like to fully replace the connectors (or simply remove them). The wires go from the positive side of battery and into the main harness via a solid blue and solid red wire. But if you see in the picture, there's two small dirty green wires in the middle. Are these fusible links? Anyone know what these wires are for? I thought the car only had 4 fusible links in the engine bay (which I have, not pictured), is there actually 6? Update: Scratch that, think i found it. Guess there is 6 total, image attached. Looks like these may not be easily replaced looking at older posts. Has everyone done a fusebox swap to address these?

Thanks for the info yall. Hopefully the temperature thing is very simple and maybe just needs topped off and burped if I'm lucky. I'll have to check the timing and TPS. I managed to find the short in my hazards circuit (fun), and circumventing that wire fixed the hazards. It shorted somewhere under the steering wheel on the way to the hazards flasher unit from the fuse box, visually couldn't find any damage. Unfortunately the turn signals still don't work, so I'll be looking into that next so I can at least test drive with some confidence of not getting pulled over.

Yeah, I have cleaned all the sensor connections key to the EFI system. Some definitely needed some attention. A couple have broken tabs that likely need to be replaced, but I think it's only CSV and thermotine that are broken, so technically if those don't connect up perfectly, it should be fine for the short term at least (except for when CSV would be needed). I drove it for the first time this weekend. It seemed to get a little warm towards the end of a 20 minute drive, ~75F outside (of course I hit every red light and prob averaged like 10mph #bayarea). It took a while to get there, but at the end of the drive it was around 3/5 of the temp gauge. Not boiling hot, but I'm assuming the car is supposed to be about 1/2 during normal op temp. I've got a lot to do, big items are: Track down a short to ground in my hazards circuit... blinkers/hazards aren't working. I saw there's some wiring that goes to the engine bay is wayyyy up in the dash. No idea to get there yet, but would be great to check those connections. Trace down this starting issue, or I have an empty switch in my cabin that I could wire up to the starter instead of troubleshooting, which I'm tempted to do if all my wiring looks "fine".. She ran great response and had good pull up to around 3k or 3.5k, but after that she just seemed out of juice in each gear, barely gaining in revs, even with pedal to the floor (just testing). Wiring or AFM or something... One of the main fuse-box wires that goes straight to the battery (and has a fusible link) has a couple KOhm of resistance in it somewhere.. Prob another wiring issue there.

welp ran through a few more things today. I did mess around with the ignition switch, but I'm not sure it's the cause of my problems for two reasons. The starter pin is is not continuous across the whole of the rotation through "Start", but it's consistently continuous towards the end of rotation, like the last 20% . The ignition pin is working as expected, through "On" and all of rotation through "Start". Either way, technically this should still work if I understand things correctly. Even if I have to turn the key to the final 20% on Start, both Ignition and Starter lines are receiving battery power (as they consistently did in several repeated tests), the dang thing should start, right? The only other variable is that testing the switch wasn't done under load. ^^ So that's the first reason I think it may not be the main cause. The 2nd reason is that while trying to chase down a short in my Hazards circuit (ughhh), I came across a beautiful connector shown in the image, look at those colors (passenger side footwell under carpet). The one wire just fell right out of the connector... I haven't looked up what that specific harness is even for yet, but I'm expecting this and some other wiring fun to be related to the starting issue. Most of the other harnesses I've inspected are no where near this bad thankfully. But this isn't even mentioning some other wiring nightmares from what appears to be a 12 year old getting lose in this car hopped up on mountain dew and holding a pair of wire snips.. I may start another thread on some wiring questions, but I'm shocked the car even runs on starting fluid right now. I found wires intentionally cut (1 major power wire it looks like), a couple harnesses not plugged in, and not to mention there's probably more corrosion lurking, even though I've been tackling it head on.. Rewiring the cut wires worries me the most, because I have no idea where they originally went or WHY they were cut ?‍♂️

Awesome, thank you Ron

Good thinking. The guy i bought it from left the old ignition switch in the car and I tested it last night. It had similar behavior to what's shown in @Dave WM's video. There seemed to be a sweet spot when turning through the "start" range where everything behaved as it should, but outside of that sweet spot, resistance was either infinite or variable. Has anyone confirmed that test with a new/working ignition switch? Mostly curious if I should expect the entire range/area when turning past "On" and through "Start" to have no resistance for the marked pins in the FSM? Or is it normal for there to be a slightly more narrow "sweet spot"? Either way, my old ignition switch has a pretty big and consistent "sweet spot" which seems like it should have been usable... I haven't checked the new unit that installed in the car now, but I will hopefully this weekend..

I did look at the ignition wiring last night, might give it a go

That's a good point, I'm not sure off the top of my head what the tach is doing, I'll have to get back to you. I think this is supposed to come into the ECU as the "Ignition trigger coil signal"

Yeah, if you wait overnight at least to be safe, it should be depressurized. Some fuel will come out regardless of what you do, so like Patcon said, be ready with a rag in all scenarios. If you're curious to follow the manual, or started the car recently, it's easy: just take off the wiring harness to that very CSV that is leaking, then wire +12v and ground directly to the CSV for 10-20 seconds (might test the harness to see which pin is ground). CSV should open and spray gas into your intake manifold, if you're CSV isn't clogged that is...

I'm right there with ya Dave WM! The guy I bought it from installed the new Ignition Assembly, but I think it's likely either not wired up perfectly, or a ground to the IGN or something isn't strong. Working alone makes it somewhat of a pain to test the stuff... but hopefully I can confirm some basic ignition wiring and the switch itself soon.

Yeah, I noticed people were trending that way too. It could be related to fuel, but as far as I can tell fuel is completely fine as described earlier. The mechanic used an in-line noid light (allows injector to still be connected up while testing) for the injectors and there was no signal when trying to start the car. Similarly, I myself have connected an LED to the injector harness (not in-line) and found similar results, by unplugging the injector harness and plugging an LED to both terminals. No pulse while cranking. While rotating the key through the ignition, I can get a SUPER short flicker of the LED, but definitely way too short to be consider a "pulse" IMO (hint hint what Dave WM said has a good chance I think). During cranking, I'm expecting a short and consistent pulse of the LED, but there is simply nothing. As @Zed Head suggested, it is valuable to know if the injectors are receiving the constant +12v during starting. If no constant +12v during cranking, then the issue could maybe be on the power-side of the injector (maybe drop resistors). If there is constant +12v to ground at the harness during cranking, then the issue is likely on the grounding side of the EFI circuit or ECU... I'll be testing that next time I have time. My thoughts are that at this point, the most common suspects are: Ignition related, drop resistors, or some other EFI wiring/ground problem. Also, I need to run tests 3-1 through 3-3 according to FSM. Some ignition and EFI tests should find the culprit, hopefully this weekend. Thoughts on easiest test to run with most useful results? I figure thoroughly testing the ignition system AND it's wiring may be a pain.

Yeah I did clean my cold start valve (CSV) and after putting it back in, it leaked as well due to old hose/clamps (and because the previous owner not using FUEL hose here). A quick trip to parts store to get a few inches of fuel hose (I believe the Inside diameter was ~8mm) and some new clamps fixed the leak right up. You might be able to swap the hose without taking the CSV out of the intake manifold, but it's probably tough/impossible. If you do unscrew and remove the CSV, there will be a gasket in there that you may want to replace. Right now I'm running without a gasket: since the intake is under vacuum, I doubt it will leak fuel there, but it may let some extra unmetered air through ?‍♂️ https://zcardepot.com/products/cold-start-valve-gasket-280z-280zx?variant=19280903962737#

Good deal, when I took it off the firewall, it actually looked like the area had gotten some attention recently, but hit it with a wire brush anyway. And yes, it is a troubleshooting loop at times, but the forums have been very helpful to bounce ideas off of. With all the bad connections/grounds I've encountered already. It seems like I could be down this path for a while. The car has a dead-man switch installed in the cabin and wired to nothing in the engine bay right now. I'm tempted to wire this up to the CSV so I can manually trigger it instead of using starting fluid lol...

Thanks siteunseen. Hard to tell if there are multiple wires going to that firewall ground, I know I only had the one black wire.

Ah yeah, I did those. It just didn't fit in my screenshot. All of 1-8 tests passed with basically no resistance.

Ahh, ok. There was a random wire that was grounded to the firewall near the battery. Had no idea what it was for, but cleaned it up anyway. Can you elaborate on the ground test? Test 1-8 in the FSM passed and seemed to relate to the grounds to the ECU wiring harness. But I'd love to have a more thorough test of the overall grounding. Is there a detailed test in the FSM?

Interesting... The negative side of my battery only had one thick wire to it, nothing else. It went straight to the big engine/transmission ground bolt (cleaned it up). Maybe that plastic connector/wire is "grounded" somewhere else, or maybe it's just dangling back there somewhere. Any ideas where that EFI ground comes from or where I should look? Next time I'm with it, I'll definitely check power to the injectors during starting.

This the first group of tests some of you may recognize from the FSM. At the beginning of today, I flunked this thing BAD. Spent a lot of time tracing down grounds/wiring issues and made some improvements. Results of before and after are: 1-1 (throttle valve) Before: Fail, 2-3Mohm. After: Pass 1-2 (throttle valve open) Before: Fail, open circuit After: Pass 1-3 (AFM) Before: 180 ohm, 180 ohm, 100 ohm After: Same 1-4 (air temp sensor) Before: 1.7 Kohm (weird temp reading) After: Pass, 2.3 Kohm 1-5 (water temp sensor) Before: Fail, 8 Mohm After: Pass, 2.3 Kohm 1-6 (air regulator) Before: Fail, 27 Mohm After: 61 ohm (?) 1-7: Pass 1-8: Pass 1-9: Pass 2-1: Pass 2-2: Pass 2-3: Pass Where a "Pass" is a resistance of just a few ohms. Even after "fixing" these wiring issues, still won't start. Injectors still not pulsing while cranking. I didn't have time to focus strictly on EFI wiring, but cleaned as many grounds as I could get my hands on. Maybe drop resistors aren't supporting enough current, or issue at relay pins like Zed Head mentioned...

Gotcha, good to know, makes sense as it was a lower power LED bulb. A few things on the AFM. Relatively sure the AFM is actually a new unit (more parts someone threw at it). The vane opens with ease by hand. I'm working on my own and can't watch it during startup. But I'm actually spraying the starter fluid in a tube connected to the AFM, and since I'm getting a sputter at least, I think I can assume the vane is opening at least some. Battery is 10 months old, spent most of it's life on a battery tender in a garage. I tried the jumper cable start (my working car has a solid 12.8V or so) and didn't make a difference in terms of starting. I also tried starting for 15 seconds non-stop in the jumper cable config and no dice.