Zed Head

It's probably running rich. Without the AFM, the ECU only adds idle enrichment fuel. When the AFM is attached the extra fuel from the flap movement probably makes it extra rich. Your shop should check the coolant temperature sensor for function and make sure that they didn't accidentally connect the sensor plug to the thermotime switch by accident or leave it disconnected. Two plugs on the thermostat housing that look the same but have different functions.

That is some different kind of logic there. Which hose did you remove? What do you mean by "no longer run well"? Did it run well before you replaced the intake gasket?

There's plenty of thread left for the double-nuts. You can't beat that method if it's possible, you'll get enough grip to break the rest of the bolt right off. Try all of the methods, none of them should make the broken piece more stuck. Put the nuts on before you tap on the top of the it though, before you damage the threads. Heat and cool the area around the stud several times while soaking it with PB Blaster. Try to twist it out but don't over-do it. You might find that it comes out pretty easy, the top probably broke off because the bolt was stuck in the thermostat housing, not the head.

One for sale on hybridz.org - http://forums.hybridz.org/index.php/topic/104039-r200-diff-sale-336-390-lsd-378/page__pid__972945#entry972945 Shipping could cost you though. The R180 should work fine if you don't beat on it. Datsun used it on a lot of models even though the R200 was available. Who knows maybe it's inherently quieter.

It's odd that a factory turbo car would have an R180. I don't believe that that is the standard diff. It's fairly easy to swap between the two, from my understanding. Something needs to be turned upside down and you might need a new rear diff mount, from what I've read. But the necessary bolt holes are on the car already. Might be easier overall to get an R200 from a wrecking yard though.

I think he might be talking about the large rubber piece that fills in between the bumper ends and the body. They are all saggy, cracked and chipped up after years of sun, heat and abuse. I've been pondering mine recently also. I haven't seen a reproduction piece anywhere either. I'll probably take them off and see if some later model trim from another car can be customized to look good, but with the plastic bumper fascias everywhere it will probably be difficult. One option might be to remove them, then push the 5 mph bumper shocks in to tighten up the gap. You could probably retrofit on the 77 or 78 pieces also, but then you'd have the accordion piece look on the wrong year car. It's a dilemma.

The 20 minutes at 2000 RPM seems to be the standard procedure for breaking a in a new cam shaft. As far as breaking in the rest of the engine, I believe that the focus is on getting the rings to set to the cylinder walls properly and that will be more dependent on the type of rings and the cylinder wall finish, which should be specific to the type of ring used. I would look for the ring manufacturer's recommendations. There are a ton of custom "this is what I do" break-in procedures out there, like your friends lugging procedure. Many of them are based on odd, incomplete ideas about how an engine works, and what happens during break-in. You might have answered this in a previous post (I can't remember for sure), but why are using the E-88 head on your L28? Did you modify it with the the bigger valves? An N42 or N47 will give you the same CR but with bigger valves, for more power. Just wondering. Good luck.

Have you checked both sides? Maybe the side you're looking at is broken. They seal at the bottom, so the top could be broken off and it would still hold pressure. http://www.carpartsmanual.com/datsunS30/DatsunZIndex/Brake/RearBrake/ToJul76/tabid/1735/Default.aspx

The heads are also drilled for carburetors as an alternative. Place the intake/exhaust gasket on the face of the head and you'll see where the studs go. The carb holes will be blocked. There are good drawings in the FSM also - http://www.xenons30.com/reference.html

WZ, I edited your original post for brevity. I have a couple of questions and some comments, if you don't mind. What brand of pump are you using? I'm no expert on brands, just wondering for the record. If you look back at my post, I mentioned that I tried two different 1978 FPRs. One leaked down to about 15 psi right away, the other held pressure at >30 psi, consistently. So there's no guarantee that a used factory FPR will hold pressure. Also, who knows about Beck Arnley quality? They're mid-level quality, I believe. I mentioned a check valve that I was using. I had my check valve on the return line, because it was the FPR that was leaking down. Sounds like you had yours placed on the assumption that the fuel pump was leaking down, stopping fuel from flowing backward. Mine was spring-loaded and designed to hold one psi ( I was just trying to keep the line full). I'm not familiar with yours, if it's an inertia or gravity type valve, it might not work on the return side. As far as results for me, after going back to the 1978 FPR that actually holds pressure, I've only had one very small hot start symptom after a long drive and short visit to a supermarket, a typical scenario for the problem in the recent past. It only stumbled for about 3 seconds, as opposed to a few times before going to the stock FPR, where it felt like 30-40 seconds of waiting (praying) for it to stop. I've also made several trips where it normally would have exhibited some hot start symptoms but got nothing. And the FPR I'm using holds pressure overnight. The engine actually started on one revolution this morning, No more fuel pump priming, which is great, because the novelty had worn off completely.

This web site is getting addictive - http://www.carpartsmanual.com/datsunS30/DatsunZIndex/Brake/FrontBrake/tabid/1733/Default.aspx - it's worth a few million words at least. Someone on this forum pointed it out, I can't remember who, but thanks for that.

Some say that certain brake pads squeal more than others, without the shims. But the shims are pretty much guaranteed to remove the noise. I had the same problem, the low speed, embarrassing "just as you stop at the light surrounded by all of the other cars" squeal. I tried all of the fix-it goos, high temperature grease on the back of the pads, shaping the front edges of the pads, etc. Nothing worked except the shims. I got my shims from a parts car that I had picked up in the meantime. You might find a set in the wrecking yards, if you're in a hurry or want to save a few dollars. They sit right behind the pads. $20 to MSA to remove the aggravation is worth it though.

In Post #29, n your first picture, that white thing with all of the wires attached is your ballast resistor. The blue wire is attached at the post on the far right. I think that you've already tested it though, but it wouldn't hurt to check again. In the second picture, off of the positive post of the battery there is a second small wire with a green wire spliced in. That green wire is where the green fusible link would be, but it looks like someone may have replaced it with plain old wire. The connections get rotten so someone may have "fixed" it in the past. You should put a fuse or link back in that spot to save your EFI components. It would still be worth your time to pull an injector connector and measure voltage, or use your noid light to connect one side to ground. If you have voltage, the noid light will light. No power at the plug, no injector opening. The early ZXes have a similar relay that will work also. The only difference is an extra, separate ground terminal, the plug and the internals are the same. The Z relays like yours ground through the case.

Pull an injector plug and check for 12 volts there. Both sides will have 12 volts. Current flows when the ECU lets it, causing the injector solenoid to move.

The ECU opens the injectors after it sees three sparks, from the coil (the ECU has to see the "fire" to know when to give the "fuel"). You can have spark, but no gas from the injectors, if the ECU does not get the signal from the coil, to open the injectors. The cold start valve will supply enough gas to start the engine but stops supplying gas when the key is not at the Start position. The details of how the EFI system works are explained in full in the Engine Fuel section of the FSM. Edit - forgot one important thing: the ECU opens the injectors by grounding the circuit. If you don't have 12 volts at the injector plug with the key at Run or On, the injectors will never open. That's why I asked if you have 12 volts at the injector plug with the key On.

I've never had to use the ignition lead wire for anything so can't really say. But you can check for power at other places, like at the coil, to see if things are working right. I saw in your first post that Pin 10 is getting power. That should mean that one of the the green fusible links is intact, at least. I think that the other supplies the dropping resistors and injectors. Have you checked for power at the injector plugs with the key On? The ECU won't fire the injectors if the circuit to the tachometer, with its inline resistor, is not in place. I've had the resistor fall out and my engine wouldn't run until I put it back in. It looks like a small (about 1/2" wide by 1 1/2 " long) black piece of plastic with a male and female plug on the same end. It should be taped up in the harness by the relays and fuse box. Or you might just have a bad connection at the tachometer. I have also confirmed that the engine won't start if the tachometer is removed. I'm not clear on why, maybe it's a pull-down line for the ECU circuit (I barely know what that means). Are you using the stock ignition module? It uses the same blue wire from the coil (-). The wire branches out after leaving the coil. Edit - just saw your last post. You could be getting sputter from the cold start valve. Injectors could still be dead. Pretty easy to make the injectors fire, with a jumper from the coil (-). It will tell you a lot.

The EFI Bible should really be called EFI Cliffsnotes. The book it's based is the FSM. Notice that the "Bible" always refers you to the Service Manual when there's a problem. Download the FSM and read the Engine Fuel section, along with Body Electrical. It has much more detail specific to your year. There is a separate set of green fusible links (either one or two) for the EFI harness, inline with a wire that comes directly off of the positive post of the battery. It should be clipped to the side of the big metal relay cover right in front of the battery. The ECU fires all of the injectors on every third spark produced by the coil. It "counts" the pulses through a wire from the negative post of the coil. The tachometer circuit plays a part also, if the tachometer is removed the injectors won't fire. You can test the ECU and circuits by connecting a wire to the negative post, turning the key On, and tapping the wire to ground. You should hear the injectors open and close on every third tap. You'll also get a spark at the distributor on every tap. If you can't find the "ignition lead wire" you can test for power to the control unit on Pin 10 at the ECU connector.

#14 in the picture on this link - http://www.carpartsmanual.com/datsuns30/DatsunZIndex/Engine280Z/Accelerator/tabid/1624/Default.aspx

I see that you're trying to do everything from a phone. Find a computer and spend a few minutes on it. On Google, the ignition lead wire shows up as the main wire from the center of the distributor cap. But that will only have power when spark is generated, so it's probably not the one you're looking for. If you're checking for spark, you can do everything you need to do right at the coil, with a voltmeter and a jumper wire.

Take a picture or copy the photo you're talking about and post it. Describe the booklet you're looking at. Describe the problem you're trying to diagnose. OR. Type "ignition lead wire" in to Google and a picture will pop up.

I had a check valve on my return line, but found that it quit working after a short while. It was only designed to hold to about one psi anyway. I know my lines were emptying because I could hear a large quantity of bubbles in the tank for about 20 seconds after I turned on the pump (I have a switch for priming). The best check valve is a fuel pressure regulator. So I dug through a few parts that I've accumulated and found an FPR that regulated and held full pressure with the pump off. Replaced my Aeromotive FPR with it last night and will see how things work now. Hopefully, a good 30+ psi on a full rail of fuel will keep the injector bodies cool enough (that's my hypothesis of the moment that seems to fit the facts) to avoid the hot start problem. Basically using the fuel as a conductive cooling path. Since I first installed the Aeromotive adjustable FPR (I bought it 'cause I knew my stock FPR was bad and the Aeromotive was on CL for cheap at the time, plus I thought adjustability would be nice in the future) I've made quite a few changes and coincidentally ended up with a fuel rail that fits the good regulator, which is the two port, 1978 style. So I am essentially back to a stock 1978 fuel setup, in my 1976 car. I also tested another 78 FPR that I had and it regulated fine but leaked down to 10-15 psi as soon as the pump turned off. With all of the sitting that these old cars tend to do, I suspect that there a lot of marginal FPRs out there, with seats that don't quite seat.

I would check fuel pressure first. With a fuel pressure gauge, you can check your pressure before and after the filter change and know if you did anything. The gauges are a little spendy and you think you won't use it much but the they're a good tool for problem-solving. If it ran for 20 minutes then conked out, a faulty fuel pump might be more likely, or a clogged fuel inlet. If the filter is clogged it will still be clogged when you test pressure. Either way, with a gauge you can confirm pressure before taking it out on the road.

Actually the sensor might have an effect at all temperatures, despite what the FSM says. The FSM says it is essentially out of the picture after 158 degrees F, but it's been shown (see BRAAP's EFI work over on Hybridz) that it still does have some effect at higher temperatures. Plus, it would be surprising for your engine to be fully warmed up after 6-8 blocks, so a shorted temperature sensor would be something to look at. Don't forget fuel pressure, while driving - after 6-8 blocks. Several people have thoguht that they had good pressure but found that the fuel pump was over-heating and losing pressure under load. I've had one in the garage that looked fine for 10 minutes then slowly crapped out. No fuel pressure, no fuel = lean condition. I've read road test reports from the past that talk about the 280Z EFI system's lean surge problem, even when new. If you read Fast Woman and cozye's threads you'll learn about the typical fix (seems to be more prevalent with the 78 cars) of adding a resistor to the water temperature circuit to richen up the mixture, across the whole temperature curve. Another possibility is the AFM. My 76 had similar mid-throttle lean intake popping, bucking and stalling, but much worse than what you describe, it was generally undriveable. In my case, a rebuilt AFM fixed the problem. Take some measurements, cold and fully warmed up and something will probably show itself. You can't get very far with these EFI systems if you don't take measurements.

I really don't know much about oil pumps, I've never even had mine off, let alone apart, but the FSM, EL section, suggests that the pump should still turn with no gasket. Clearance is measured from the base of the pump body down to the rotor, implying that there is clearance without a gasket. This is from the 1976 FSM, which is better illustrated than the 1973 FSM. Just an observation.

Beware those tires. Rubber will age and degrade just through oxidation alone, even out of the sun, no matter how much Armorall you apply. 38 years is way old.