Zed Head

I just realized/remembered something about the 1976 year and vacuum advance - you only get vacuum advance in 4th gear. It is controlled by a solenoid which is activated by a switch on the transmission. Unless it's been bypassed. So fixing the vac advance will only matter in 4th gear. One of those odd Datsun things they did for a few years for emissions.. Sorry to throw a damper on the potential for improvement with a fixed distributor. The car still needs drivin' though. Get the gas flowing through the injectors, hot oil washing the crud off the valve stems, warm up the valve seals so they seal better...it will add up to smooth things out. Climb some hills, put some load on it, rev it up. Bill Clinton was long ago.

Maybe you should just take it out and beat on it! You'll get your frustrations out, have some fun,and from what I've read and my experience with my own car, it will run better when you get done. Not joking! Your vacuum reading might go up also if you have gunked up piston rings. You might actually be losing your timing light signal to a different wire or just poor "induction" if you are using one of the clamp-on inductive trigger timing lights. Next time it does that, move the clamp to a new spot, away from the other wires and close to the plug. I've seen the same thing and it wasn't the engine, it was the clamp position. There is a second adjustment on the bottom of the distributor that would give you more "twist" on the distributor but I wouldn't worry about it right now. Are you still running without vacuum advance? I see an obsession starting with a number on a gauge (vacuum). How does the car run and drive? That should be your focus (in my opinion). My car was sitting at 16 inches for quite a while but I just lived with it and focused on other things and drove it around (with a few hard "tuning runs" thrown in). Months later, I checked the vacuum, even though I had stopped caring about it, and it was at 20 inches. There is no relation between spark plug tip shape or length, and ignition timing. It only affects how hot the tip runs. They are specified to run just hot enough to stay carbon free, but not so hot that they cause pre-ignition. Your car is stock so the stock plugs should work fine. Your thread is looking like you have many objectives in mind - getting a high vacuum reading, getting rid of the exhaust popping, removing the gargling sound, etc. If it was my car, I would fix my vacuum advance (because without it your engine will still be a little sluggish at part-throttle operation and you suggested that you had poor pickup), set the timing between 10 and 14, and drive it around for while. Take it out, run it through the gears hard a few times, get it nice and warm. Then re-evaluate what single thing you want to improve next and focus on that.

Tomohawk, thanks for the advice. You know what's funny though? - It only hides the avatars when you're logged in. If you're logged out, they're still visible. But that's okay...

Hey Darrell, sorry to make a scene, I should have just sent a message. Thanks for the new picture though! The other one was just a little jolting to the senses. Good luck with your project. I would just put a voltmeter at the battery while the engine is running and slowly rev the engine up and see what readings you get. If everything is working right, the voltage will probably rise a little bit from idle, then stabilize above ~1200 rpm somewhere around 14 - 15 volts, depending on the temperature. There is a actually a procedure in the FSM with a table of voltages but I think that it's a little bit complicated and convoluted.

The points ground the coil primary circuit so that it can charge up the secondary circuit then break the circuit when they open, causing the secondary circuit to discharge to the plugs. Primary is the two lugs on the coil, secondary is the main terminal in the middle. If you disconnect the coil negative, you can check for continuity through the points to ground, with an ohm-meter, when the points are open and closed. Then you'll at least know the points are working. Attached a picture...

Howdy Steve. I spent some time trying to figure out what this vacuum advance switch was on my car and found that it was an emissions feature that actually advances the timing in high gear. My limited understanding of emissions is that retarded timing gives "cleaner" exhaust, maybe that's what they were trying to do. Attached a copy from the 1976 Emissions Controls section, page EC-9.

argniest, if you have not done much mechanical work, there is a high probability that you will strip a screw head. It takes some practice to get the feel for when the tools are working right, plus it takes some correctly applied strength to get them out if they're very tight. Another option for you might be a #2 screw driver bit used at the end of an extension, on a ratchet handle. This would allow you to press down on the ratchet head, and use the leverage of the handle to turn the screw. Just offering alternatives. I have been turning screws, nuts and bolts for years and I still had problems getting the screws out of a manifold with the original injectors in it. Watch the screw head and if the bit starts to slip, stop and readjust. It's a sick feeling, looking down at a rounded out phillips head screw.

Just to be clear,and I hope I'm not making a mess here - on a car forum, I really just want to see car stuff. Your avatar could be Fabio with no shirt on and I still wouldn't want to look at it. There are several other avatars that I wish I could block out. It would be nice if there was an option to not show avatars (maybe there is, I'll start looking). FastWoman, there are two screws, inside, accessible through two small holes, in the back of the meter. One moves where the needle sits and gives immediate effect, the other doesn't do much. I don't know what the electronics terms are for these adjustments. You have to take the meter out, make an adjustment then plug it back in to see what happened, since the wires are short. I just set mine to what my multimeter showed while running, so I would know if things were going bad while driving.

It is much easier to get to the injectors with the fuel rail removed, otherwise you have to tweak and bend the rail. They're all mounted to the rail with the same very short piece of fuel line, which gives very little wiggle room. I highly recommend buying a high-quality #2 Phillips head screwdriver before attempting to remove the screws. It is very easy to strip the heads of the screws if the bit does not fit perfectly. If you strip the inside of the head you'll have to get in there with Vise-grips or some other tool. Avoid that at all cost. Craftsman brand (bought at the store, not internet) has a very good fit. The popular penetrating oils are PB Blaster, Liquid Wrench, and Kroil to name a few. You should spray it around the base of the injectors where the screw's threads are. Spraying at the top might not get down to them. Spray it on when the engine is warm if you can.

What SteveJ is saying here is that the voltmeters are quite often not accurate. Don't use where the needle is pointing for anything more than knowing that there is "some" voltage above battery level (where ever the needle sits when the engine is not running). They are adjustable, through two screws accessible from the back. You should measure voltage at the battery at various RPM to feel confident that it everything is working right. At idle the alternator isn't really spinning fast enough to test the regulator. Edit - by the way, and no offense intended, but your avatar picture is hard to look at. Is it necessary?

Did you measure the fuel pressure or just see that the pump is working? Low fuel pressure could give a lean condition, which could cause backfires, and lack of acceleration. Edit - another possibility is timing too advanced. Are you the damper pulley has not moved, and that your timing is truly relative to Top Dead Center?

The symptoms are the same that I had when my Air Flow Meter (AFM) was bad. But you show that you have replaced yours. Did you get a new/rebuilt one or just a different one?

Congratulations on the "new" car and good work on finding all the important numbers on the engine. You probably know already about the free FSMs at http://www.xenons130.com/reference.html . Even with the modifications, there's probably still lots of useful information in the FSM for you. A couple of notes on your pictures - your fuel line is about to split open at the carb (fire!) and it looks like the filter might be bypassed (rust!). And your brake fluid is low in what looks like might be a non-stock master cylinder and reservoir. What's under the distributor cap, points or the electronic ignition setup?

Your symptoms don't really indicate a bad ignition module. But, regarding the HEI module that you installed, yes, you do have to ground the case of the module for it to work correctly. A grounding lug is molded in to one of the mounting holes. It is well-documented in all of the installation instructions (surprising that missed it, hope it didn't do any damage) that you have to ground through one of the mounting holes. Some people even run a separate ground wire from the mounting hole. From what I've read (I have one on my car but it has always been grounded, so can't say for sure) they will be damaged internally if they lose electrical ground. Might be worth grounding it and trying again. The critical mounting hole has a wide flat grounding area, it's easy to see. Edit - If you have a voltmeter, check for battery voltage at the coil terminal, both sides, when the key is on and when cranking. Also, the magnets under the stator plate can break on the 280ZX distributors. Connect a voltmeter to your positive red wire from the distributor and see if it is generating the voltage pulse necessary to fire the module, while cranking,

A new clue! - it died while going up a steep hill, but it did run and drive for ten minutes. It either died because the engine was loaded and that made a problem worse, or maybe it is a fuel supply problem. Did you have a full tank of gas? How far did you go (ten minutes at 55 mph or ten minutes at 15 mph) before you climbed the hill and how far up the hill did you make it? What did it do before it died, did it cough and sputter or did it just quit? Climbing hills takes more gas supply than just cruising. The better your description the more ideas you'll get back. Just trying to help, you could give more information about how the car actually runs, when it does run.

Coincidentally, I just ordered one from OReillys, picking it up tomorrow. 1976 280Z. Baxter Auto Parts and Autozone carry them also. Autozone ships to your house from orders off their web site.

If one half-shaft moves (rotates) with the wheels on the ground, it could be a u-joint or both (or loose splines but that is unlikely, I believe). With wheels on the ground the half-shafts should not rotate at all, they should be locked solidly on to the wheel. It's hard to see the u-joint move with the half-shaft on the car, even with a bright light and your head twisted in to a good position. Sometimes you can stick a screwdriver in the joint and wiggle it around. Look for signs of rust at the seal also, I had a dry one on my car and you could see some rusty residue around the seal. It didn't take much movement to get an audible clank/clunk. You can remove the half-shaft working from the wheel well of the car,with the wheel off.

Are you sure that you're not putting them on backwards? Datsun did not use the red = positive, black = negative that domestic cars use. I don't know what happens if you do, but it's worth confirming. Or, could your key be in the On position when you were connecting the battery? Maybe you heard the fan motor? Make sure that the key is off and that you don't have any positive wires shorting to ground. If you have an ohmmeter, you can check the positive cable to see if it has a path to ground BEFORE you reconnect the battery. Put one lead on the negative terminal and one on the positive, without the battery in. If you don't have infinite resistance then you have a short or something is on. Or if you have a test light, hook up one battery terminal, then test from the other unconnected cable to the remaining post. If it lights up, then you have a short or something is on. This will let you find your problem without frying anything. Hopefully you didn't melt anything,but you should probably check your fusible links and look for scorch marks.

I forgot about that one. Which is funny, or not, since it actually happened to me once. The message of the evening is check the clutch components for proper operation.

You will find that the fluid is low. It is probably in the slave cylinder dust boot. Odds are good that your slave cylinder is bad. If you keep forcing the gears, then something really will be wrong with your transmission. Search "slave cylinder" or "clutch problems."

Another good material for cleaning oxidized, tarnished or corroded connections is 3M Scotchbrite. It's not as aggressive as most sandpapers and leaves a nice shiny surface with no grit. It will also hold up to WD-40 or Deoxit or a typical contact cleaner. You can cut a small piece and use pliers or a screwdriver to get in to small places. argniest, I don't know what your weather is like, but if you can get the car out for a spin, you'll probably be more able to translate all of this new knowledge back in to a new description of what your car is doing. I went back to Post #1, and the original issue was that it was down on power and getting poor gas mileage. If you do too many things without re-establishing a baseline you can get lost. I saw your comment about your headlights magically coming on again. That is a sign of oxidation in the headlight switch or in the dimmer switch, from sitting and not being used. From what I've experienced and read on these forums, the old "use it or lose it" axiom applies in full force on these old cars. The headlights on my car didn't work when I got it, but I haven't had a problem since I used some Deoxit to get them working and use them quite often now. Sometimes you can just spray contact cleaner in the switch and work it around to brake up that oxidation. Yours will probably stop working again in the future when the temperature and humidity changes unless you start using them regularly.

Can't really understand what the problem is. Can you be more descriptive?

This is on the 72 240Z in your profile, right? Did it run before you installed the ZX distributor? And have you reset the timing? Your idle will drop if the timing is retarded with the new distributor. No good ideas on the high-reading gauge. Check your ground, maybe they read high as resistance goes up. One more thing - which year did the distributor come from? Your centrifugal and vacuum advance curves could now be quite a bit different from what you had before.

Too bad, I thought you were the lucky owner of four cars, plus parts. Like FastWoman suggests, I have used Liquid Paper/Whiteout to mark the notch. It seems to hold up well. I think I found mine by putting the car in high gear and slowly rolling it along the garage floor by hand so that I could make sure that I saw all of the damper pulley. You can't tell what you're missing when you try to bump it around with the starter.

The 77-79 5 speeds and 4 speeds used 3.54 diffs. You should check the FSM or the diff itself to be sure which ratio you have. I think that they changed ratios in the 4 speeds somewhere between 74 and 75, so might have changed diff ratios too. Edit - Agree with Fixitman. He beat me to it. Still worth double-checking what you actually have.