Zed Head

The 77 file is the whole FSM, the 76 or 78 is broken in to chapters and will probably download and unzip. They all use the same sensor. Engine Fuel section.

Could be a vacuum leak, letting air bypass the AFM, causing a lean condition. It sounds like the fairly common lean back fire. Higher RPM might overwhelm a small leak, letting the engine run correctly. At low RPM the vacuum leak dominates. Check the big rubber hose after the AFM, the PCV hose, the breather hose to the rocker cover and the various vacuum ports on the intake manifold. Spraying carb cleaner or starting fluid on the intake/head interface and listening for RPM change will find a leaking manifold gasket.

That's a lot more information than in your previous posts. If you had a stuck valve on #4, you should be able to wiggle the rocker arm up and down on the stuck valve a lot more than the others, when the cam lobe is pointing up. The valve lash will be very loose. Or, if you've tried to adjust the valves, the lash might be too tight, holding the valve open. I think that I've also read of the lash pads coming loose and jamming the valve open. Compare how # 4 looks and feels to the one right next to it. With the plugs out, you might be able to spin the engine with your starter jumper and watch what the valves do. Some oil might spray though so have some rags handy. No fuel to the rail and good pressure up to the rail doesn't really make sense. Fuel provides the pressure so you can't have pressure without fuel. This is kind of unintelligible also - "I can voltage with the ignition switch on, but no continuity". Not sure what that means. I would spend more time looking at the valves and rocker arms on #4, and then squirting some oil in to the cylinders and re-running the compression test. If it's rings oil will add some sealing and pressure will rise. If not, it might be a valve or something else. If the intake valve was stuck open, you might get a big backfire, pressuring the crankcase and blowing your dipstick out. That much pressure might have also damaged your AFM, unless the backfire happened while it was disconnected. Maybe you got lucky on that one. Which part of the #4 spark plug was broken? That doesn't sound good either. Taking the head off is a whole new set of problems. Your engine might end up looking like the car in your avatar.

mjr, you've jumped past what your tests showed and maybe spent a little extra money. When you jumped the starter and it worked, you showed that the starter was OK. You probably didn't need to replace it. When the engine fired a few times but didn't keep running unless you used starting fluid, you showed that you have spark but no fuel. For a 75 with fuel injection, there are several reasons why the injectors might not fire. You should focus on that as the reason it won't stay running when the starter is jumpered. When you had the ignition switch apart, you might have tried turning the electrical switch with a screwdriver in the slot (maybe you did this?). This would tell you if it was the electrical switch, the wiring to the starter, or the mechanical part that turns the electrical switch when you twist the key. Basically, break the system down in to what works right and what doesn't. A basic logical approach works best when digging in to these cars, especially with the EFI engines. Even after you get it running, there will be tuning issues that need a similar approach. Good luck.

dont know what pintara is, what is compression ratio of engine with pintara pistons and p90 head? i think that your teck (sic) man said that it would ping with advanced timing not without.

Try the jumper. It will tell you something about whether it's the starter or the ignition wiring. You can also jump directly from the main stud to the blade, using a screw driver.

Is the small gauge yellow wire connected to the male blade connector on the starter solenoid, and making a good connection? You can test starter function also, by running a jumper wire from this blade and touching it to positive on the battery (low budget remote starter). If it cranks, you have a problem with the wiring, if it doesn't, with the starter.

I was off by 1/2 year. Dang. Here's a really good read on Z car differentials - http://forums.hybridz.org/index.php/topic/49194-differential-cv-lsd-hp-torque-r160-r180-r200-r230-diff-mount/

I don't think the R200s were used in the Zs until 1975, in the 280Z. You either have an R180 or someone swapped in an R200.

You should adjust the back brakes using the star wheel to as tight as you can without dragging. The excess volume from your loose back brakes probably isn't allowing enough pressure to build up before bottoming the piston in the master cylinder. It's not good for the pistons in the rear cylinders to travel far in their bores either.

Your distributor shaft might be off a tooth or two. Apparently it's not uncommon. Or your plug wires could be off one spot at the distributor cap. If you find that the pulley mark is at TDC, you can either moved your plug wires over one spot or see if the distributor shaft can be moved. Two options.

Since you've had it apart, you've seen the thin narrow rod that turns the switch. You can take two pliers, and twist/bend that rod in the direction that the key turns, to get it to move the electrical switch farther when you turn the key. My car had a similar problem where sometimes it wouldn't start (maybe the same, your description isn't very clear), probably just from mechanical wear. Bending the rod fixed it.

If you have a voltmeter you can work from "first principles". The coil positive terminal needs power when the key is On and at Start. Turn the key to On and find the wire with power, connect it to the positive terminal. Do the same with the key at Start. I would do this anyway just to verify the wire colors are correct (for example, one person's green might be another person's blue).

If you've owned the car since it was new then the only way you should have an external regulator is if you or one of the mechanics who had worked on your car had installed one, unless there was some odd factory leftovers. Nissan went to the internal regulator in 1978. I'm no expert on the history of these cars but that would be a very odd thing to have on a 1979 car. Do you have picture? I converted to an internal regulator on a 1976 car, but in retrospect there was no real advantage gained besides availability of parts, and maybe reliability, except for the fact that the rebuilt alternators available today usually fail at the internal regulator. An external regulator might actually be more reliable unless you use Nissan-made internal alternators.

It could be fuel pressure. Steady fuel pressure at the factory spec. is necessary for the ECU to do its job right. Even if the pressure looks good at idle or tested with the engine not running, sometimes the fuel pumps will lose pressure at higher flow or when they get warm. Knowing fuel pressure is one of those things you have to do. I recently picked up a brand new pump (shiny) from the wrecking yard and it only lasted about 20 minutes while I was testing it at home. It had had some water in the fuel lines (gallons according to (the yard guy said 4 gallons came out of the tank) and must have rusted the guts of the pump (luckily they threw it in with the spare engine I was buying, so no real loss). It may seem like a waste to buy a pressure gauge for $40 only to use it once or twice, but you can save a lot of money in the long run. Many people recommend hooking up the gauge, running the hose out of the hood where you can see it, and taking the car for a drive while you watch it under load at higher flow. Pressure should not go much outside 30 - 38 psi while you're driving. p.s. Just re-read my other post and it seems harsh. Sorry about that. Good luck with the car.

A walk though the wrecking yard might be worthwhile if there are any Zs or ZXs there. I found a set that looked either factory new or newly rebuilt. Nissan brand. Often, people will replace many parts before giving up and junking a car. You can tell at a glance if the injectors are new, old ones are typically rusty and corroded.

I think that the B came after A (of course) and was available as an option in 77 and on. Just what little I've gleaned since getting my car. The company linked below really seems to know their stuff and show a rebuild kit for 77-83, which would be the B 5-speed. He'll respond if you send an e-mail and probably if you call. The rebuild kit price doesn't look bad either. http://www.datsunstore.com/index.php/cPath/27/sort/2a/page/4

Most people who don't post prices know that their price is high, in my experience, or don't really know what they want but are hoping for a pleasant surprise. I wouldn't worry at all about insulting someone who doesn't post a price. Personally, I feel insulted when someone posts an ad but no minimum price. I insulted someone a couple of weeks ago about a part (an engine), then had a nice e-mail exchange with them, showing by example why their item was over-priced. I then found what I was looking for, in better condition, a couple of weeks later, for a "reasonable" price (reasonable to me). It was funny, because they had lots of reasons why my offer was too low but still wouldn't say what they thought was reasonable. 10 miles is not far, I would go out and look then insult away if you want it. Don't ask them what their minimum is, they will quote a big number and won't be able to back down with out looking foolish. Make your offer first. Expect to be rejected though.

Good luck. Sorry that some basic standards of communication and civility are too much. Just a few more capital letters probably would have been enough. The return on the small investment of time and effort would have been great. Try www.zcar.com and see how that works out.

You'll be much better off if you read and consider the suggestions people give you, and act on them. Either you didn't do that with Zedyone's post, or you did and decided not to take the suggestions. Your last post is worse than your first, and barely understandable. Effort returned to you will be proportional to the effort you put in. Backfire through the intake is a sign of a lean mixture. Fuel pressure and vacuum leaks are two potential causes.

Did you try this suggestion from FastWoman yet? This will test the electrical circuit from the battery, through the dropping resistors and injectors, to the ECU connector, but without the ECU in the picture. Break the problem down in to chunks, then break the chunks in to smaller pieces. Edit - It's not clear what you mean by positive and negative terminals. You said the ECU connector gets voltage but not clear if you mean the injector pins or elsewhere. Pin 10, for example, gets battery voltage to run the ECU functions. If the injector pins show voltage then your problem is either the ECU itself, or the trigger signal from the coil negative, or the resistor and tachometer circuit. You never did confirm that that the tach was working. The ECU won't work right without that circuit.

You could go stock EFI with the F54/P90 combination and be pretty well guaranteed of a good running 280ZX power-level engine, with the engine harness, ECU and AFM from a ZX (75-78 Z parts would probably work also). The 2.8 is 17% bigger than the 2.4. More power. Even with carbs. Sounds like you're trying to mix and match 2 blocks and 2 heads for some benefit. There might not be any. Even with the E88 for higher compression, I think that you would lose overall from the smaller valves. If you don't want to go with EFI, the F54/P90 combo with carbs would still be pretty potent, relatively low cost and fewer problems since the parts are already matched and working together. I assume, unless you're rebuilding the engines. If you're rebuilding, there's probably a better combination of parts out there.

Both sides of the injector circuit will have power. The transistor in the ECU allows more current to flow at the appropriate time. With the key On you will see battery voltage on both sides of the dropping resistors, both sides of the injector connector and all the way up to the transistor in the ECU. That's how circuits that work by grounding function. Power everywhere up until the very end, where the grounding happens to cause an action.

I actually learned the trick from some Tony D posts, but have verified that it works. I agree on the electrical. I was intentionally vague on the 11 volts. Let the OP do the troubleshooting to find out why there's not 12.6 at the connectors. Somewhere from the battery and its charge, and through all of the various connections (fusible links, etc.) there is a cause for the lack of voltage.

I missed the green and red LCD comment, which does suggest that the ECU is grounding the injector circuit. I took the title at face value - "no pulse to injectors". Sounds like the real problem is "no gas from injectors." To add one more to FastWoman's list - 11 volts might be too low to get good current through the injectors to get them opening correctly. You should have a full 12.6 volts (fully charged battery) at the injector connectors. How long has the car been sitting? There have also been cases written of, where the injectors are so gummed up from sitting that they won't open. Another way to check if your ECU is "seeing" the coil and triggering the injectors, is to connect a jumper to the negative terminal of the coil, turn the key to On, then repeatedly tap the jumper to ground quickly. The ECU will fire the injectors on every third tap. It's quick and easy because there're no other noises like the starter cranking or the engine turning over.