Zed Head

It's probably the Unilite or the MSD box. Both electronic. One easy thing that you could do is to disconnect the MSD and just run the Unilite. If the problem still happens it might be the Unilite. The Unilite should have its own ignition module. Also, if you do take it out again watch the tachometer needle immediately after the problem happens. I assume that it is manual transmission. Hopefully there is room on the road to leave the car in gear so that the engine continues to turn. If the engine is turning but the tach needle is not moving then you have a spark problem. Apparently Pertronix bought Mallory. Can you take a picture of what's under the distributor cap? Not clear what exactly you have. https://pertronixbrands.com/products/pertronix-ml-182-ignitor-mallory-unilite-8-cyl

There's always a way to not get things done. It was a concept idea. You could poke around in the port hole too. Ponder why the gauge needle would move so rapidly when it's just sitting there on the small channel to the oil filter, which is like a big buffer pool of oil. Anyway, just offering ideas about what I would do. I really hate how Google or eBay or whoever adds so much extra crap to eBay and Amazon links. Probably contains all of my recent browsing history, in code. Here's a picture instead.

I think I already wrote this but I would spend more time on being sure the pressure reading is correct. If you get it back together without discovering the source of the problem. The small passage that the gauge is ported in to could have flow disruptions that give erroneous readings. If there is a constriction or obstruction the fluid could have a low pressure point at the gauge port. The fluid is moving. If it was mine and I was unsure I probably would have tapped a hole in to an oil filter and stuck my gauge there, just to verify what the gauge port showed. The filter is full of very slow moving oil.

Some people think the multiple discharges reduce the number of misses at idle. So it might help a bit for emissions. This still seems like an odd thread. Lots of work to try to fool the emissions tester. Whatever you think about the purpose of the laws, really, this thread is about breaking the law. Why not stick with stock, pass the test legally, drive it around while you're in CA and build a separate motor the way you want it to be? You don't even know what the stock engine is like. You can do the lightweight flywheel and lower gearing without worrying about emissions.

I think that you might have to get Piston #1 to the bottom of its stroke so that the counterweight is up in order to get the pan off. Too late but I would have spent more time at the oil pressure gauge port and maybe even at the oil filter when everything was together. Watched some oil come out, see what it's doing. Oh well. You'll know a lot more about your engine when you're done.

Can't tell much from the pictures. It's the same basic EFI system that the USA 280Z's use. You can even see the EGR valve in one of the pictures. The key is probably somewhere in whatever was changed from when his dad was driving it to now. Something that got disconnected or bumped or moved intentionally.

What are they? He is convinced that he only has 10 - 13 psi at any RPM. Are you suggesting that he needs a new gauge? Or that 10-13 psi at the gauge port is just fine? No offense, but your posts are of the "nope, not right" variety, but no concrete actions suggested. What should he do now? He has a new gauge, he made a fuzzy video. What are you suggesting today?

Seems like a lot of effort being expended here that will most likely lead to failure to pass. As I understand California they have the visual inspection, the idle emissions measurement, and the 2500 RPM cruise emissions measurements. Three chances to fail. I used to spend a couple of hours messing around back and forth at the emissions station in Oregon (free checks as you long as you're making improvement), dialing in the AFM, the timing, sometimes the fuel pressure, so that I could pass just idle emissions. On a 76 with no catalytic converter, mostly original engine parts. The MSA AFM that I had bought in the past just ran rich at idle so I would have to change back to an older original AFM that I had picked up. Then after a couple of years of dinking around with the engine just to see what it would do the idle emissions would be out of spec again.

So, what path forward are you suggesting?

I think that you're headed in the wrong direction Wally. I only mentioned the oil filter relief valve as an example of a relief valve. The pressure is still caused by the resistance to flow of the main bearings and head oil supply orifice. The pump produces pressure which forces the oil through the passage that the gauge port is on. If there's nothing holding the flow back then pressure will be low. I'd put the old oil pump back on before doing anything else. If pressure is still low then the problem is farther down the line. Or on the supply side, with air leaks or obstructions at the oil pickup.

157 posts before that one. Too many to go back and try to figure out the history of the transmission. 3rd and 4th use the same shift rod. Are you shifting with the clutch pedal down? Rolling the car a bit? You said "shouldn't it go in to gear if in neutral". Doesn't make sense. Neutral is not in gear.

Your question specifically said California. https://asktheref.org/Services/Smog-Check-Results-Review/ Why did my vehicle fail the smog inspection? Vehicles can fail a Smog Check for any number of reasons, some common reasons for failing a smog check include: Excessive tailpipe emissions Modified with non-approved parts or computer programing Check Engine light or OBD monitor failures Faulty sensors or computer controls Vacuum leaks Other

It's probably like having half of a shroud. You won't know if it's a problem until you're sitting in traffic on a hot Texas day. But you'll have a possible improvement to add if it does overheat.

The great thing about the early EFI systems is that they are very primitive and the service manual has an in-depth explanation of what each component's function is. Since it ran before and was even drivable then it seems like something that you did afterward caused a problem. Might help to go back and discuss why you made the changes that you did. Did it stop running right after you fixed the fuel tank or did you do some other things also? Maybe you should undo some things and start over. Put the old FPR back on, etc. There might be hoses to the intake manifold and throttle body that you moved or left disconnected. For example, the auxiliary air regulator (AAR) is in the vicinity of the fuel rail and has hoses and an electrical connection. If it is not right you could have starting and running problems. Also, all air must pass through the AFM. No intake leaks at all. The only planned intake leak is the one through the charcoal emissions canister. Not even sure that a German 280Z would have a charcoal emissions canister.

36 psi while running is not right. The EGR can leak internally, within the ports on the intake manifold itself. Even with the a plate on the top. You'd have to block the bottom hole too to be certain. You said that you tested the TPS (actually TVS). Did you test at the ECU connector? Best to do all tests at the ECU connector as described in the 1980 EFI Book I linked above. Did the fuel canister on the front have a pump that gave proper pressure at the rail? Not really clear how things were when it ran for you. Might be that the PO "tuned" the system around a bunch of wrongness and you'll have to undo all of that wrongness.

Your fuel pressure should drop when the engine is running, to somewhere around 30 psi. If it doesn't it could be because the vacuum hose is disconnected or because intake vacuum is very low. People have reported problems with rotten EGR passages causing big vacuum leaks. It's hard to see them because the holes are inside the EGR passages.

According to the FSM there are three states for the switch. Idle contact (2) connected to 18, full throttle contact (3) connected to 18, and none of the contacts connected to anything (inside the switch). There is no state where 2 is connected to 3. So what you described is an odd thing.

Helps to pull out the specifics. But, it's out there now. Still don't know what Nissan used though. It was the early days of disc brakes. Surprised that they did not mention it in the FSM if it was there and important, but did mention the volume of the reservoir. Those early FSM's are like text books, very thorough. Every component explained in detail. Test bench anybody? I don't have any parts or a garage to work in right now. Maybe later. If the MC does maintain residual pressure then opening a rear bleed valve should get a small squirt. Not sure exactly how the proportioning valve will affect the end pressure but it looks like there should be some maintained (want to go back to math class - read the description of the proportioning valve). Anyway, there's a lot out there but still not clear what's what in the end. Can't go wrong with F and R though.

That's a good point Cliff. I glossed over the fact that the TPS was connected before but is not now. Having the TPS disconnected would be like having the throttle pedal partially open. No idle enrichment and no full throttle enrichment. According to the FSM. Not clear what "bypassed " means though, above. Another switch that might be disconnected is the AFM plug. Not uncommon for it to fall off as you're trying to get the AFM plugged in and back in its hole. Really at this point it would be a good idea to go through the electrical tests in the EFI Guide Book. Lots of other stuff that could be unplugged and affecting things. Coolant temperature sensor, for example. Electrical tests here. Good practice with the meter. Nissan has some weird formatting in the FSM.

Try to find the glue blob marks and put it back exactly where it was. The only reason to adjust the AFM is to fix the last guy's adjustment. I assume by calibrating with weights you mean the atlanticz procedure? http://www.atlanticz.ca/zclub/techtips/afm/index.html

I've never had my ignition timing off by much but I do know that when it is advanced idle RPM goes up and when it is reduced idle RPM goes down. I did have a situation though on my first car where timing was so reduced that the engine would barely run. Beside that though, ignition timing that is off by a lot can cause engine damage. Reduced timing can cause overheating and advanced timing can cause detonation. So it's very important to have it correct. As far as your specific problem just keep in mind that, generally, the engine will rev as high as it can for the amount of air that is supplied. A thought that just came to mind is that maybe the AFM vane is stuck or sticky, blocking air flow. You can pop the black cover off of the side of the AFM and watch the counterweight move as air flow rate changes. It should move easily. You can also affect the fuel-air ratio by moving the counterweight which will move the vane. The farther open the vane the more fuel the ECU supplies. The cover is easily pried off it is only held on by a tight fit and maybe a few drops of sealant. And, don't overlook the not uncommon mistake of leaving a rag or paper towel somewhere that it's not supposed to be.

No offense, but NO, not even close. Actually, that is close, the starting point, but not close enough. You need to finish with a timing light. Here's a video showing how to set ignition timing. It's very important. This one covers the basics without a bunch of fluff.

You're saying that the problem is fixed now? Did you order the wrong product or did the wrong nuts get put in your package?

Using a timing light to see that the mark on the damper pulley is correct in relation to the marker on the front cover. Sometimes timing can be so far off that the engine just won't run right. This thing... Picture from here.

p.s. once the engine is running things like the coil and relays and fuel pressure become less significant. Ignition timing is important though. Have you confirmed that?