FastWoman

I think it really helps to use a single pan electronic balance if you have one. You can make your weight however you wish. FAIW, Zed Head and I played around with a calibration method that used voltage output as a function of weight against the air vane. I think it's a valid approach, but unfortunately neither one of us had an AFM we could 100% trust as being correct. Anyway, you can find the relevant posts somewhere around #225 (both before and after) in this very long thread: http://www.classiczcars.com/forums/showthread.php?40392-76-280Z-Question-on-dist-manifold-vacuum-dist-timing-fuel-pressure-brake-booster/page11

Ah! Well, now! Yes, you have a very good find there, indeed! So do you see the red "Glue Blob" label in the top photo? That's the set screw for the wiper. Loosen that, and re-set the wiper arm to where it travels from end to end on the trace (rather than undershooting the low end and overshooting the far end). I'm trying to remember the year of your Z. Does your fuel pump use the shutoff switch in the AFM? If so, you might be able to carefully bend the arm of the switch mechanism so that the switch will stay closed when the engine is running. But yes, moving that wiper arm will definitely make your engine run leaner! I'd say that's your smokiest gun! If I were you, I'd do a full re-calibration of your AFM. If you're even a little bit careful and thoughtful about what you do, it's not going to fly apart in a million pieces and ruin your day.

Excel!

WOW! You've done quite a lot! I suspect you've still got multiple issues going on, although you've apparently eliminated most of the major stuff. There's no way the yogurt cup test was inconclusive when I did it, so I'd say if you're scratching your head as to whether there might be a leak, there's DEFINITELY a leak somewhere -- or multiple leaks. However, they would probably be small leaks. As a guideline, my intake system would hold pressure for maybe 20 sec when I "inflated" it. The glue blobs in the AFM don't look factory to me, so perhaps someone did molest it. The blobs don't look neat or small enough, and I believe the blob in the center should be a dot of red lacquer (?), not silicone. So I'd say that's your most likely culprit for rich running. I'd look at the Atlantic Z site for the article on adjusting/calibrating the spring tension ("the beer can method"), and I'd go through the tests in the FSM. The TPS is your other potential problem spot. I'm not sure what is left/right on the thing, but it needs to be calibrated not by RPM, but by throttle position. Make your adjustments with the engine stopped. You want the idle side of the switch to make contact until the throttle JUST MOVES FROM ITS REST POINT. At that point neither side of the switch should make contact. This should continue until you're maybe at 2/3 throttle, at which time the other side of the switch should make contact. You should adjust and verify this with a multimeter. Although it's tempting to suggest you need an "anti-resistor" , I think addressing these last small issues will bring you home. When you think your engine is running about right, you should replace your plugs, drive for a hundred miles or so, and give your plugs a read. You want a nice mocha/tan coloration on the insulators. If the insulators are black/sooty, you're still running too rich. If they/re white/gray and chalky, you're running too lean.

Yes, your WIRES are probably just fine. As we've been trying to say, it's a switch or connection (e.g. ground) that's at fault somewhere. I think Pete's suggestion of juicing the various switches (particularly the dimmer switch) with contact cleaner is a good one. I'd also trace the ground wire from the dimmer switch to the ground point, take that connection apart, clean it, and bolt/screw it back down. Putting a dab of dielectric grease in there before bolting/screwing it down is also a good idea. I'd bet money that your problem lies somewhere between the dimmer switch and the ground. I suppose it's also possible it could be a fusible link issue, but I think you'd notice other things not working too.

1972 240Z (It helps to know this.) fuel starvation bad mechanical advance on distributor failing points spring binding in the SU pistons? any number of other things Can you be more specific? Are the cylinders missing? How do the plugs read? How recent is your fuel filter? Do you have adequate fuel pressure?

I think the common denominator in the wiring (between low and high beams) is the ground. I'd check that first. You can download the factory service manual for free (!!) at... www.xenons30.com Welcome, BTW!

Just make sure your alternator is running at the right voltage! You don't want anything higher than maybe 14.6V. (Even that's a bit high, but I think Datsun liked to run their voltages high-ish.)

Dunno... I know it was very bad form, but I reused my O-ring when I re-did my tank. It looked in good condition, and I made certain all surfaces were clean and smooth. As far as I could tell, no leaks. I suppose someday I should top off the tank and pull the inspection plate to be certain. Anyway, you might indeed have your O-ring askew.

True, Enrique! It's not just Ace, but most of the smaller hardware stores, many of which are independent. My go-to place for stainless fasteners is our local True Value. Not only do they have a great selection, but their prices are actually quite good. Because of the importance of boating to our community, we also have a number of auto parts stores with large stainless selections. And of course there's always the marinas! FAIW, www.boltdepot.com has some nice stainless variety boxes in metric, very reasonably priced

You need to see where your voltage drops are with the alternator in place in the running engine. That will tell you where you've not got continuity. Connect the (-) probe of your multimeter to the case of the alternator (E terminal), and probe the following: -- Engine block (should be almost exactly 0 V) -- (-) terminal of battery (should be almost exactly 0 V) -- (+) post of alternator (should be approx 13.5 - 14.5 V if voltage regulator is regulating correctly) -- each side of the fusible link (should be same voltage as (+) post of alternator) -- (+) post of battery (in theory should be the same as alternator pos post, but might be a fraction of a volt lower) Any deviation from your expected voltages will reveal the trouble spot(s). Wherever you've got a suspect connection, measure the voltage across it. It should be 0 V. If you have a voltage greater than that, you've got a bad connection.

Hester, I had never looked at Steve's parts link. (Very nice! Thanks, Steve!! ) However, if you're not wanting to pay $3 for each screw (or whatever they charge), you can use generic metric screws. The thread pitches are pretty standard. If it fits the hole, the pitch will almost certainly be right.

^^^ Good idea about the steering rack and bushings! I'll have to remember oven cleaner. Sounds like a great idea! Threehz, the propane torch is for breaking loose frozen bolts/studs/nuts. When you heat the things up, they expand and squirm slightly in their threaded holes. That fractures the rust/corrosion. As the hardware cools, you spray it with PB Blaster, which then flows into the fractures. Once the hard corrosion has turned to an oily, crusty powder, you have a chance of backing the stud/bolt out. This technique is particularly useful for steel studs/bolts threaded into aluminum, as the aluminum expands faster than the steel. I simply couldn't have removed at least 5 or 6 of the studs in my cylinder head without the torch! I don't think there is much you need to know about removing the manifolds. You'll probably get better advice here than you will get in the FSM, as the FSM isnt' really meant to tell you how to service an antique car with loads of corrosion. Here's what you do: First hose down all the bolts/studs/nuts with PB Blaster NOW. Do it again tomorrow. Do it again the next day. Keep those things soaked for as long as possible before you start work. Since you have the luxury of tilting the engine, position it with spark plugs down and manifolds up, so that gravity can be your friend. Then start unbolting the manifolds. I'd say use the blow torch method if you encounter resistance, except that you don't want to risk warpage of the manifolds. Turn the nuts/bolts/studs firmly and steadily, and give them time to move. If one rings off... well... it happens. After you've removed the manifolds, then you have to remove the studs. To remove an intact stud, jam a couple of nuts on it, and back it out by turning the lower nut with a wrench. If it offers resistance, torch it. If you're removing a broken stud with no thread left, turn the stud with a SHARP/NEW pair of vice grips. Be VERY careful not to break the stud, because your last option is then to drill it out. You don't want to get to that point! Go slowly and methodically, and ask for advice here on the list before doing something you think might be a bad idea. If you get tired, get some rest and come back with a clear head. After you've gotten all the studs out, clean out all the threaded holes with a tap. (Pay attention to my warning about the thermo housing!) To clean out a hole, squirt it full of PB Blaster. Screw in the tap a few turns, back it out, and clean it off. Then go a few more turns, back it out, and clean it off. You don't want to load up the flutes on the sides of the tap with corrosion, because it can jam in the hole and even break. It's an easy task if you take your time. It could become a miserable task if you were to get careless and take too many turns with your tap. Next, clean up all of your mating surfaces. I like using this sort of rasp for the job: You can lay it flat on the surface and slide it, and it cuts away any debris quite well -- in a perfectly flat plane, no less. After you've cleaned all your mating surfaces, blast out all your threaded holes with compressed air -- or chase out any debris again with a tap. Now reassemble per the FSM instructions. I followed ZTrain's suggestion of using a touch of Permatex cement around the exhaust ports. So far that's worked fine. Last step: Clean off as much oil as possible from your exhaust manifold. You'll have an impressive plume of smoke when you first fire up your engine -- normal. Oh yes, add to your tool list a torque wrench. You'll need that for torquing down the manifolds to spec. All of these tools are very cheap at Harbor Freight or Northern Tool.

Paint is cheap, if you want to throw some paint on your engine. It's mostly elbow grease. You can de-rust with a medium strength solution of muriatic (hydrochloric) acid. Wear gloves, apply repeatedly with a paint brush, and let the acid slowly do the work. Rinse well, and then apply Ospho (phosphoric acid), which will convert any flash rush and render the surface paintable. Both of these products can be found at the hardware store. Then use your choice of engine paint, available in a spray can at your local auto parts store. FAIW, leaks are fairly common in these older Z's between the manifolds and the head, particularly around the #6. They often slip by inspection. An intake leak will cause poor running, and an exhaust leak is both noisy and potentially dangerous (CO entry into the cabin). Anyway, if you DO have an intake/exhaust manifold R&R in your future, it's a lot easier to do it when the engine is removed. You'll have better access for drilling out studs, turning studs with vice grips, etc. It CAN be a miserable process having to do all this with the engine in the engine bay. (Your back will get quite a workout.) If it helps you to size up the job, a local Z specialist quoted me $800 to R&R the manifolds. This price would have included re-using whatever studs didn't break. His expectation was that he'd have about 3 that would break and require removal/replacement. The problem with this approach is that it leaves mostly weak studs cemented in place with corrosion, particularly if there were any oozing coolant connections nearby (e.g. around the #1). It's best to extract all the studs and start fresh. I'd say that approximately doubles the work. So if you choose to take this on, I'm guessing it would probably be about a 2-3 day job for you. Tools would include an ordinary hand tool collection with a couple of long 3/8 extensions, a propane torch, and a good/new pair of vice grips. Supplies would include PB Blaster or Kroil and some nickel antisieze (available from a nut/bolt supplier, approx $20). Parts would include the gasket and a new stud/nut/bolt set (from MSA), which I think would run you under $100. You'll also have to learn some Japanese metric curse words, BTW. The American SAE curse words sometimes don't work.

You can get a box of assorted metric screws from your local auto parts store. However, they won't be painted dark olive green like the originals. I suppose you can paint the heads with black epoxy spray paint (appliance paint) from Home Depot. Black makes more sense than dark olive green, don't you think? BTW, welcome... and love the literary name!

This ebay seller (f0rrest) puts together a good little kit: http://cgi.ebay.com/ebaymotors/injector-connector-kit-6pc-datsun-280z-280zx-300zx-_W0QQcmdZViewItemQQhashZitem43a04f8954QQitemZ290452375892QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories The heat shrink he provides is of very high quality, and he even throws in a packet of dielectric grease. The connectors themselves seem a bit flimsier (or at least more flexible) than the original Bosch, but I don't think that's a significant issue. If you give them a hard wiggle, you can pull them off without first undoing the wire retainer. I suppose that can be either a good thing or a bad thing. All of mine have performed quite well over the past year. I'd recommend getting additional connectors for your cold start valve, air regulator, thermotime switch, and coolant temp sensor, as well as one spare. Why a spare? It will make testing of these components soooooo much easier! I just picked up a separate 4 cyl kit from him (I think it was for a Jeep), but maybe there's a 5 cyl kit. Either that, or just ask him to put together a kit with 11 connectors. He's a pretty nice guy and will surely do it for you. The 3-conductor throttle position sensor connector is best obtained at a junk yard. You'll probably have to live with your AFM connector in whatever condition it is. The good news is that it's in a pretty protected place and is probably in good condition. But yeah, while you're into rewiring the injectors, I'd just do the whole engine. If your engine harness is like mine was, you'll make a couple of discoveries in the process.

In that case... Well, if there's any chance you're going to R&R either the intake manifold or the exhaust manifold/header, then this is the best time to give it a go. Those studs can be cemented with corrosion into the head. Depending on how long you intend to own the car, you could save yourself a LOT of frustration, pain, anger, blood, and heartache down the road by breaking these things loose while you still can. MSA sells replacement studs, BTW. I'd pull the thermo housing off the head, clean up the threads, and replace. When you chase out the threads, pay special attention to the forward most threaded hole. There's a chain guide just beneath it. You can pull off the valve cover and watch the backside of that guide as you screw the tap in. You don't want to bend it! Perhaps the water pump? It's no fun replacing that with the engine under the hood. How clean is your engine? This would be a great time to pull the oil pan and clean out your engine from top to bottom (sans the cylinders). I assume you're also repainting the engine? Other than that, everything is very easy to reach/service on a Z. I'd just fixate on breaking loose any corroded nuts/bolts/studs/screws, cleaning, and painting.

I'd consider repainting the engine bay. There's no better time. Prep it, and drag it into your local el-cheapo auto paint place (Maaco?) to have it shot for a couple hundred bucks. Or spray it in semigloss black.

Systematic is good, grant. Although Eric is right that the CTS is a pretty cheap item, I suspect there's something else going on besides a failed sensor. I say that because resistors (including thermistors) tend to fail by opening up (infinite resistance), rather than shorting or partially shorting. I suspect there's some issue in your wiring. Either that, or you're not looking at the correct pin when looking for #13. I'll be very interested to find out what your finger tweaks of the AFM mechanism reveal. It's very quick and easy and will tell us quite a lot.

Yeah, it sounds like something electrical/electronic is overheating. I'd suggest having a can of starter fluid close at hand. When your engine fails again, you should immediately pop the hood, pull one of the vacuum hoses off of your intake manifold, and squirt some starter fluid inside. Reattach the hose, and give it a crank. If it fires up briefly, you have a fuel problem and should start scrutinizing your EFI. If it doesn't fire at all, it's probably an ignition problem, and you should check out your ignition module and coil. If it fires up and keeps running.... well... then you're going to have to wait for it to fail all over again, because you weren't fast enough to catch the problem.

Grant, your air temp reads a bit warm -- around 120F. Your engine compartment might have been a bit warm. It would be better to take a reading when your engine cools off. Park your car in the shade, so that the air temp sensor would be approx the temp of the outside air. If you get another "hot" day of 70F , then you should get a reading of about 2.25 to 2.75k. Something is definitely off with your coolant temp sensor reading. At 180F you should get a reading around .29 - .36k. After remeasuring your air temp sensor on a cool engine in the shade, I'd do the same with the CTS. You should get that same 2.25 - 2.75k measurement. Assuming you're really getting that low a CTS resistance, I'd pull the connector off of the CTS and see if you get the same reading between the two pins. You should get the same resistance. Then with the CTS connector unplugged, re-measure from 13 to ground at the ECU connector. You SHOULD get an infinite resistance, but it's possible you have a short. Anyway if you've got a 13-to-ground resistance of 46 ohms when warm, your engine should be running pretty lean. Either your sensor needs replacing, your wiring needs attention, or both.

Patcon, that's exactly the approach I want to take with my own speedometer. It reads a consistent 10% too high. I'd also love to know what a German style plate looks like. Do you have a pic to delight our eager eyes?

Maybe you mean .68 kOhms between 13 and ground? A reading of .068 would be quite low and would result in very lean running. You'd best double check that one. Asolutely change out all the vacuum lines! It's quick and cheap. You'd be surprised how many little splits and breaks the average old car has in its vacuum tubing. I'm guessing you'll find at least 3. And yes, do the valve cover gasket too, if it looks as though it needs it. Be certain everything is tight. (And let's hope you don't have an intake manifold gasket leak like I did.) The silicone caulk blobs in the AFM might be factory. I'd need a better picture to tell, but they did use silicone glue/caulk. Mine was sort of a translucent milky white -- not as clear as yours. Now that you've got the cover off, warm up your engine, and then turn the mechanism just a bit while the engine idles. Try to find the highest idle, and read your vacuum there. Then guesstimate how far CW or CCW you've rotated the thing from where it normally wants to rest. That will give us some idea how rich or lean your mix is.

Hmmmm... Well, I suppose Homo is just a bastardized form of Australopithecus. The market wanted a car with a better ride, and thus the 240 evolved into other forms. I suppose that could be called "market selection," or at least that's what I think Darwin would have called it if he were an economist. This evolution is not a good thing if you're after a lean, mean track machine, but if what you want is a daily driver GT sort of car, the 280 is probably a better fit. At least that's why *I* own a 280 and not a 240.

I had an Edelbrock oil/foam-type filter on my Mustang that was about 10 years old. It was getting a bit fragile. As far as I can tell, the paper filters get much dirtier than the foam/oil ones, which is a very good thing.