Zed Head

What color are the wires? Red is positive, from the magnetic pickup (reluctor). If you have a rebuilt, they may have spliced wire extensions on that are the same color but you might be able to see the original color up by the pickup. From what I've read, the other way to find out is to just hook it up and watch your timing mark. Apparently, if it's connected backwards the timing will be erratic and unstable. If you get an unstable timing mark, swap the wires and re-time. Make sure that you have a good ground to your mounting posts, they are the electrical grounding points for the module internals.

The voltage meters on these cars are typically inaccurate, so the 15.5 reading may not be right. Have you had a voltmeter on it at high RPM? I wouldn't trust the stock in-dash meter. They can be adjusted via the screws in the back though for future use, but you'll still need an accurate volt-meter to do it. The wiring looks typical of someone jumping the plug instead of cutting the wires. You can check Blue's site to see if the colors are matched correctly. They don't match by color, but by function,and there are several "extra" wires afterward. Is the "11" reading (accurate or not) at idle, at night with the lights on? Or is it while driving? It sounds more like a weak alternator, low idle speed, or too much current drop through dirty connections. The Z alternators put out just enough amperage at idle to get the job done, if everything is clean and working correctly. Even an extra 500 RPM of idle speed can make a difference. I have also found that a 10 year old factory alternator from an old parts car performs better at idle than a brand new rebuilt parts store alternator. The parts store alternators are of generally low quality. I had mine die within a year.

Double post. Love the site, but it's still very slow...

Here is a picture from the FSM. You can see that the wire to the transmission switch is powered when the key is On. Apparently the trans switch is normally closed, so the solenoid is powered in gears 1-3, blocking the vacuum passage to the distributor. In 4th gear, the switch opens, power is cut to the solenoid, and vacuum is applied to the vac advance. If the solenoid doesn't have power, you will have full time vacuum to the distributor advance. So if you don't have the wire to the solenoid, you really don't need to do anything except watch out for the other loose wire end from the trans, which will have power. Or take everything off and connect the vacuum hose directly to the vacuum advance (with one loose wire still to worry about).

Ran fine when parked! Ten years ago. Not mine, just thought someone might be interested. The one side that's shown doesn't look terrible. Ridgefield is about 20 miles north of Portland OR on I-5. http://portland.craigslist.org/clk/cto/2389207775.html

They are fairly easy to twist out of the top of the diff. You might go to a local wrecking yard with a pair of pliers. Don't squeeze too hard if it's a plastic one. I think that the later Zxs came with metal. Maximas and maybe Subarus might use the same went.

The ECU holds the injectors open longer as the AFM vane opens farther. With a vacuum leak less air flows past the AFM, the vane doesn't open as far, so the injector open time is shorter, giving a leaner mixture. The ECU also takes information from the temperature sensors and the tachometer. The Engine Fuel section in the FSM describes it all, with graphics. Fuel pressure can affect the mixture also. Have you checked your fuel pressure and fuel pressure regulator? When mine went bad, the engine ran very rich.

The Zs don't have a donut gasket like chevy's do, they just have a plain old flat two port gasket at the exhaust header/manifold junction. A leaky gasket really shouldn't affect cold running or crappy power-making. Changing the intake/exhaust gasket probably won't help your problem. If you do decide to do it anyway, you'll probably break a bolt or two on the thermostat housing and a stud or three on the intake/exhaust system. Search ez-out, tapping, broken stud, etc. before you start to know what you're heading for. From my own experience and what I've read, you will break at least one stud in the head and have to put extra effort in to getting it our before you'll be able to finish the job. A vacuum leak would cause it to run lean. Extra resistance in your water temperature sensor circuit would cause it to run rich, one among several rich-running possibilities.

The real question is not about color but about amperage rating. Is 0.3 mm ^2 a typo also (the size of the "brown" link used for the headlight and other circuits)? Would the headlights draw more amps than the fuel injection harness - green 0.5 mm^2 link? Courtesy Nissan sells a red fusible link that is 0.3 mm^2 in size, which would be a lower amperage rating than the green link. But the altlanticz page says that red is a larger size and higher amperage rating (0.69 mm^2 - 50 amps) than green (0.5 mm^2 - 40 amps). The Datsun store doesn't tell the size or the amp rating of their red link. As I said, it probably matters little in function. I'm just trying to understand where the idea came from, that those red (or Br) links should be replaced with 50 amp maxi-fuses or similar.

If you search transmission swap, 240Z, or 280Z on Google, this forum and other forums you will find a lot of good reading. This topic comes up all of the time and there are several good write-ups around the internet. The 2+2 probably has the 240mm clutch and flywheel, and your 260Z has a 225 mm setup. So you would need to move the flywheel over also.

Do you have the vacuum advance hooked up to full manifold vacuum instead of ported? That would give you an extra 10 - 18 degrees of advance at idle and increase your idle speed.

I can't remember if the vacuum switch solenoid is normally powered or not. Just make sure that the disconnected wire or plug doesn't have power to cause a short in the future. Always a good idea to test disconnected plugs for power and cap them off if they do. I see that you found the BCDD. There should be a black wire coming out of it to connect the yellow wire to.

Have you checked your fusible links? Specifically, the Ign link and its circuit? When you connect power to your coil positive you might be feeding power to the ignition circuit, bypassing the fusible link.

I would just connect a ported vacuum source to the distributor for vacuum advance all the time for peppier engine response and gas mileage, connect the BCDD wire to avoid backfiring and stinky exhaust when decelerating in gear, and trace out the wire to your water temp sender using the 1976 diagram. That should be all that you need to get back running well. Edit - and the water temperature sensor of course, but I think its wire comes from the main FI harness.

With a wiring diagram you should be able to determine where those three wires connect. Saridout made up a full color PDF diagram for 1976, search his name on this site if you don't have it already. The vacuum switch solenoid allows vacuum to the vacuum advance canister on the distributor in fourth gear only. It seems to be for emissions, apparently advanced timing is dirtier than retarded. I bypassed mine so I get vacuum advance in all gears (we run E10 in Oregon so I figure I'm breaking even on pollution). The BCDD is that weird looking thing on the bottom of the throttle body,with the rubber cap. The yellow wire supplies power to a solenoid when the ECU tells it to. The water temp switch (not sensor) tells the ignition module when to use the other pickup in the distributor to advance timing by ~6 degrees. This appears to be to keep the idle speed up when cold. When the engine gets warm it switches back the the retarded pickup. I don't have the stock module so I don't use the switch anymore. In between the time that the AAR closes and the engine gets up to full temperature I will get a pretty low idle sometimes. If you still have the stock ignition module (I don't) and 4 speed transmission, with fourth gear switch (mine's gone), and distributor with two pickup coils (I'm down to one pickup myself), you could get yours to work correctly.

The yellow wire goes to the BCDD. The plug that you have labeled Harness 1 plugs in to a another plug with a red, white and yellow wire that appear to go up to the sensors in the thermostat housing. On my car that condenser plug connects to a black wire that is grounded to a distributor mounting bolt. My car does not appear to have been messed with much, but I'm not sure why Datsun felt the need for a separate long wire all the way to that point, but that's where it goes.

The attached picture of page BE-6 from the 1976 FSM shows where the Br (Brown) came from. Notice that it is also the smallest gauge of the three. If your fusible link block has not been too damaged or worn out, there will be a label on the side designating Bl and Br as the fusible link colors. Somewhere over time brown became red or maybe the factory links never did come out brown in color to match the FSM. That may be how a 0.3 square mm brown link turned in to a thicker red link. Color didn't match gauge and someone went with the color code for replacement. In the big scheme the safety margin that most engineers use probably makes it irrelevant. It's just interesting how some information gets a little warped and propagates.

The insert is basically an internal shock absorber. You should be able to press the shaft down in to the body like you would a normal shock absorber. Even the gas-charged ones only have low gas pressure and can still be worked up and down, the gas pressure will slowly push the shaft back out of the body after pressing in. I don't think it should move side to side at all. If might help if you defined "slightly". 1/16, 1/8, 1/4"?

Blue, I'm curious - all signs point to your page with and Wayne Monteath as responsible for propagating the notion that what should be 30 amp links are actually 50 amp. From your page - (Thanks to Wayne Monteath for uncovering this rare table!). Who is Wayne Monteath and how did he determine that the Factory Service Manuals are incorrect? Where did the "rare table" come from? Honest curiosity. I have only seen the Brown = Red = 50 amp link on the atlanticz site. No where else. Thanks for any insight you can offer.

The red circle is a bypassed heater core. The common leak point is the control valve, just on the other side of the firewall where those hoses used to go. The blue circle is the throttle dash pot, to keep the throttle blade from slamming shut when you let off the gas. It doesn't take a vacuum line, it just looks like it does. The hole is just an outlet for air to pass in and out of as the diaphragm inside moves. Must be a car you just picked up and it doesn't run? Why are you removing the engine?

1976 has a Brown (Br) link that estimates out to about 30 amps, based on gauge (color and gauge shown in the FSM) and interpolated between the other "known" links. Red seems to be the popular replacement for Brown, but there appear to be two versions of the Red links, the ~30 amp, which you would get from Courtesy for example, and a 50 amp which others sell. There does not appear to be any supporting documentation for Brown = Red = 50 amps, but it's out there. Be careful with any fuse swaps you do.

Most important is what the wire does, when the car is being used. I would check if it's grounded first, using an ohm-meter. Maybe it shorted in the past and has been bypassed. Then see if it is powered at the different key positions, using a test light or a voltmeter. That information will give you more clues about where it should be or was. Edit - Don't connect it to anything until you know what it does. You could cause a short and burn some fuses, fusible links or wiring if it gets power during operation.

For 1981 the FSM shows a CR of 8.8 for the NA engine versus 7.4 for the turbo engine. The earlier N42 blocks (with stock pistons), and N42 or N47 heads, ran 8.3 CR, no turbos, EFI.

You might be lucky that your order didn't go through. Apparently the owner has not been very responsive in the recent past. Read through this thread for reference - http://forums.hybridz.org/index.php/topic/62367-anyone-heard-from-ross-modern-motorsports-lately/page__pid__934028__st__120#entry934028

Are you sure that you're not feeling the benefits of an extra 9 degrees of advance? That would be noticeable by seat-of-the-pants. There is no reason for your timing to change with the new module. The E12-80s don't have any timing control like some later ignition modules do.