FastWoman

This low-tech freon reclamation method might be of use: If you can find an empty refrigerant cylinder, you can evacuate it with a vacuum pump. Note: It must be free of any oils, which it almost certainly would be. Find an R22 cylinder to be safe -- compatible oil. After evacuating it, hook it up to your AC system's low side port (engine NOT running). Put the cylinder in an ice bath, and the freon will evaporate from your car's AC and condense into the chilled cylinder. This will take some time, and the process will go faster if your engine compartment is nice and toasty. You can hear the gasses transferring by putting your ear to the cylinder. When you hear no more hissing, and when the gauges stabilize in pressure, the transfer is complete, and you've got almost all your R12 in the cylinder, ready to re-charge your system later. If you want to do a much more thorough job, use dry ice instead of (water) ice. There will be almost no residual R12 in your system. If you use 1/2 of a can of freon, you can use your new R12 tank to hold the other half (same ice method). If you don't transfer it, the can will leak the remaining 1/2 pound before you have the opportunity to use it, and our planet will also suffer needlessly for it. The big tank is much more leak-free, particularly if you cap the valve. Obviously, use this advice at your own risk. I'm not responsible for the consequences. Hire a licensed professional instead. You will die or become seriously injured. Void where prohibited by law. Some restrictions apply. Batteries not included.

One more thing: A drop-in replacement doesn't mean you can mix refrigerants. You would need to evacuate/reclaim the R12 anyway. If you do mix refrigerants, not only will it muck up your system, but nobody will want to touch the witch's brew in your system, meaning it will cost you a lot of money to have it reclaimed. You can't intentionally vent it, and the fines for doing so are huge -- like $25,000! By the time you pay a shop to reclaim the R12 (even in its unmolested state), you might as well have bought a can or two of old-stock R12 and shot it into the system yourself. As I recall, the system in my '78 holds 1.5 lb. Your system is probably a bit different.

And the million dollar question: Did your car start up effortlessly after it cooled off? Don't get too heavy into the diagnostics yet. The classic hot-restart issue is that the car starts fine cold, you run it around, getting the engine and engine compartment good and toasty, you shut down, you return 10-15 later, and the engine won't fire up. Let it sit for another hour, and it will start up just fine. Your case is interesting because you have headers. I assume you have fresh gas in the tank? I, too, am interested to hear Backdoor report back. I tried running some ethanol-free gas here, and I didn't have a hot restart problem, but my hot restart issues are too seldom for me to conclude whether that was just by dumb luck. The fuel did make my engine run a bit too rich, though, which is why I went back to the ethanol blend. Remember, I have the potentiometer mod to richen the mixture. I could re-tune for the ethanol free gas, but I don't want to have to buy all of my fuel from one gas station.

I don't have an answer to your question -- only a comment: As long as R12 is still available (which it is), it seems better to use R12. Last I checked, a can was about $30 on ebay. In fact I bought some guy's last private stock (2 lbs) for $1 a can at a garage sale. It was in a box of automotive products labeled $1 each. I remember his wife shouting into the house, "Are you sure you want to sell this stuff for $1 a can?" And he shouted back, "Yeah, $1 each for anything in the box." (I think she knew it was worth quite a bit more than that.)

Just another option to investigate: You might be able to find all the used parts you need for an R12 installation. There's a possibility you might even be able to buy a remanufactured R12 compressor. The R12 freon is still available and is cheaper than it was, shortly after its manufacture was halted. You might even be able to do an R134a adaptation of a stock R12 system. The advantage to either of these approaches is that it can become a DIY project. If you go with R12, you'll of course need to have a certified/licensed shop evacuate and charge. I think you can handle the R134a yourself without any special certifications. I think $150 - $200 is all you'd require in special tooling -- a vacuum pump and a set of manifolds.

Off the top of my head, an 18'sh or 19'ish in Hg vacuum is about 7 psi, and if you take that 7 psi off of the 36, you get roughly 29 psi at idle -- for an engine running at proper mixture. Anyway, the differential between WOT and idle should be about 7 psi, which it appears to be.

You could also diversify your family's toys. For instance, how about an old (e.g. '70's) Toyota Land Cruiser?

I seem to recall the cost of a Vintage-Air system for my '66 Mustang being around $1600 back in the late 90's (installed). I know that would be more in today's dollars, but I don't know how much more. The system was very nice, but I think the professional installation was a bit ragged around the edges. The freon lines were pointed up into the hood (touching it), and the ducts to the side vents were installed over an accessory fuse block I installed. (The installer could have easily moved it, but he didn't.) If I had to do it over again, I'd install my own. Oh, and FAIW, your decision to install AC for Texas is spot-on. I can't imagine NOT having AC there. (I've lived all over the state.) I would also recommend you consider installing louvers over your hatch glass. It makes such a big difference not to have the sun beating down in your black-carpeted hatch! I wish I had done that when I owned my Z in Texas.

It's the brand I use simply because the guy who would rebuild carbs for our boat, back when we had a gasoline powered boat, told us he wouldn't guarantee his carb rebuilds unless we treated with Sta-Bil. It's also the brand our local marina owner swears by. Having said all this, I don't really have much need for a fuel stabilizer anymore. All our cars get driven year-round, so our fuel doesn't sit for too long. Everything is fuel injected, so corrosion-clogged carburetor micro-passages are no longer a problem. And all our carbureted yard equipment gets real gas -- the old fashioned stuff with no ethanol. Oh, and we sold the power boat. Now our only marine engine is a diesel. But in answer to your question, the reason I use the product when I do (which is really seldom) is that it is so universally recommended by people I trust to know what they're talking about.

As long as you're not letting your fuel sit for months at a time, you can run it without stabilizer. It's only when you store it over the winter that you need to stabilize. I use Sta-Bil as well.

Awesome! Wow, you're the only person in the family interested in restoring this car... Lucky you! A word about bad gas: Don't just "not drive" the car on the old gas. I would recommend not even running the engine on it in the driveway. Old gas can have lots of varnish, which can gum up your valves. The problem is when a hot, gummy valve train cools down, and the varnish solidifies. Then your valves are stuck, and when you crank an engine like that, it will literally fall apart and require a rebuild -- valve collisions with piston tops, rockers popping loose, and all sorts of chaos. Please don't ask me how I know...

Hi Deb! Always good to see another female Z owner on the board! Like siteunseen says, your '76 280Z will have a (roughly) 3/8" supply hose from the tank to the pump. The actual size is 10 mm, but the 3/8" hose is only a half millimeter too small and will work just fine. You don't need the expensive fuel injection hose for that one segment. AFTER the pump, all your fuel hoses are approx. 5/16" (actually 8 mm, but 5/16" is almost a perfect fit). You'll need the (rather expensive) fuel injection hoses there -- approx $4/foot, as I recall. The one tricky little fuel hose segment is a tight, right-angle bend in the fuel pump area. That can be replaced with a short piece of copper tubing bent with a bending tool, and connected via two short pieces of fuel hose and four clamps. Siteunseen's suggestion for the Fram G3 filter is a good one that is popularly implemented. It will protect your fuel pump from rust in the tank. Oh, and these are some of the best fuel hose clamps I've found: http://www.summitracing.com/parts/cca-g3912 They come in a variety of sizes. The inside is smooth and won't cut into your hoses, and it's very flexible (well suited for small hoses). The material is stainless. Summit has some miniature fuel injection hose clamps in zinc-plated steel that look promising, but these Comp Cam clamps work so well, I think I'd prefer using them anyway (because they're stainless).

Dan, I think everyone buys control-type potentiometers from Radio Shack for the potentiometer modification, but those would be very fussy, imprecise, and prone to getting knocked out of alignment. I always recommend using a screw-adjust, 15 or 20 turn trim potentiometer instead, which can be adjusted very precisely and which will NOT get knocked out of alignment. Radio Shack apparently has this one in 1 kOhm: https://www.radioshack.com/product/index.jsp?productId=2062307&znt_campaign=Category_CMS&znt_source=CAT&znt_medium=RSCOM&znt_content=CT2032230 You can also order these things off of ebay. My recommendation is that you determine your target resistance (in your case 500 Ohms) and then find a potentiometer that's comfortably higher than that value, but no more than approx 2 times higher. (One reason your 5k pot is so fussy is that your adjustment is down in the very bottom of its range.) Happily, the 1k Radio Shack pot would be just right for you. I will note to OTHER people, though, that this is not necessarily the right value for YOUR car. For instance, my own car needs about 2.4 kOhm of compensation to run right, so I have a 5 kOhm potentiometer installed. If you want a switch as a theft deterrent, you should not have it on your potentiometer, as you would lose your tune every time you engage the switch. Instead, have a switch that's separate from the potentiometer. I would suggest wiring it in series with the potentiometer, so that when you open it, the engine will dump massive amounts of fuel. I think it will run, but it will be belching black smoke out the tailpipe, and the plugs will probably foul after a minute or two. There are better places to install a theft deterrent switch, though. You can interrupt the fuel supply with a fuel pump shutoff switch. You can interrupt the sequencing of the ECU by interrupting the #1 wire to its big-hunkin' connector. You can interrupt the power or reluctor connection to the ignition module. You can interrupt the starter control wire. I always thought a great theft deterrent would be to wire a single-pole, double-throw (SPDT) switch to the starter wire. Have the common connection wired to the key switch and the starter wired to one leg of the switch. Then wire the other leg of the switch to your horn (or horn relay?). In the theft deterrent position, the horn would blow when the thief turned the key. If you want to be a bit stealthier about it, you could power some sort of transmitter with that wire, so that you'd get an alarm signal inside your home. There are many ways to design a theft deterrent system. I think making the engine run poorly is probably the least effective of these -- because it still runs, right?

I replaced the electronics of my '78 tachometer with an aftermarket board made by rt-eng (RT Engineering) for Mopar tachs. They're sold on ebay, for instance: 1967 1974 Mopar Replacement Tachometer Board | eBay I had to disconnect the meter movement from the board and solder connections to the board, which I mounted on the back of the tachometer inside a tuna can (for a shield/housing). The meter adjusts fine to the Datsun I6. I suppose $80 is a bit of money, but at least your tach will be accurate and will last into the future.

To elaborate further, there are non-Nissan check valves that can be adapted. Someone started a great thread on it -- perhaps Captain Obvious? If you still have the pump, throw it in a box, and save it to sell/give to someone else with a failed pump, for the good of the Z universe and general good karma!

The last time I replaced mine, I used Anco. I don't know whether they fit better than Trico, but I don't recall any problems with the fit. As I recall, they supply a gazillion little plastic pieced for adapting to whatever you have.

ZH, I did miss the part about having a new fuel pump. I think 40 PSI static is shaving the pressure pretty close. When you stomp on the accelerator, vacuum goes to almost zero, and therefore pressure goes to 36 (ideally). At the same time your fuel demand is quite high. Your pressure might drop when you're dumping lots of fuel, causing you to lean out at WOT. I know that's not your "cutting out" problem, but it would still be a worrisome point to me. It would be interesting to see if you can maintain 36 PSI at WOT (accelerating on the road, with your fuel pump hooked up normally and a fuel pressure gauge zip-tied to your windshield wiper), but that's a test for another day. Yes, the reason to hook to an external test hose is so that you can watch the fuel come out the end, measure flow rate, etc. Of course you're not looking for a "tired" pump, but maybe one that's overheating and/or malfunctioning. Oh, and here's something to consider: If you don't have a good return flow, and if you're not using a lot of fuel (e.g. idling), then your pump might get hot. (It uses the fuel flow to cool itself -- or at least the OEM style does.) Anyway, by doing this, you can verify that the pump is working correctly and sufficiently. If that's the case, then the problem is in your wiring or relays. You're systematically eliminating possible trouble points this way. Here's another possible cause for your fuel pressure cut-out: Let's say you have a bad electrical connection somewhere in the line. When it passes current, it heats up, and when that happens the contacts flex slightly, breaking the circuit. You should check all the electrical connections from A to Z. You might find a black, melty one somewhere. You might have already done this, but I don't want to re-read the thread. I can't really remember what's in it -- sorry.

Count me out!

Too large a hood ornament, perhaps? :cheeky:

Very nice! I really like the look of the headers showing through where the intake webbing has been removed. Purty! Yeah, when there's a super rich condition, it's usually the CTS at fault.

FAIW, a properly running Z shouldn't backfire. To me, the sexiest sounds are of a smoothly running engine coming down to idle, stepping through various stages as it winds down -- first the fuel cut, then the reintroduction of fuel, then the BCDD. Each changes the running tone as the engine winds down. Sadly, my engine doesn't wind down gracefully like that anymore. I'd need a working BCDD. Also your running sounds will have a LOT to do with the exhaust, and there's no such thing as stock exhaust anymore. Thus I question whether there's any such thing as a classic "Z" sound. It's a very individual thing.

Before you unhook anything, identify which connector on the pump is positive and which is negative. The easiest way is to do a resistance measurement with the ignition off. The negative/ground connector will show zero'ish resistance to the body. The other will show a few ohms more. When you disconnect the one that shows a few ohms more, the resistance between that wire and the body should be infinite. If that's true, then you've identified the positive side of the pump. Now run a long wire from the battery to the positive side of the pump, and the pump should run. This all assumes your ground connection is good. It might be worth tracing that connection and cleaning/tightening it up. I believe the ground connection is inside the tool box area somewhere, but I might be wrong. Once you're able to run your pump this way, then do all of your flow and pressure tests in the driveway. Don't drive your car this way! You also don't need to run your engine during the testing, although I suppose you can if you want to. I would do two tests: Hook your test hose to the outlet of the fuel pump, so that you can test for restrictions. With the pump running (and obviously not the engine running), you should get a pretty strong and steady stream that won't diminish over maybe 5-10 min, while rocking your car around to slosh the fuel in the tank (e.g. by pushing on the bumpers). If your stream diminishes it might be because junk is clogging up your filter or your pickup screen. Then hook the fuel rail back up with a pressure gauge between the fuel filter and the fuel rail. Connect your test hose to the return barb on the fuel rail (the one not connecting to the fuel filter). Run your pump again, and observe both the pressure and the return flow rate. They should remain steady over time. If your pump is tired, you might find that the return flow rate starts to diminish until it stops altogether. If this happens, then you probably need a new pump. (This assumes your system passed the first test without clogging up.) Note that to do these longer run-times, you can put the end of your test hose right into the filler neck of your fuel tank. If your hose isn't long enough, I suppose you could fill one gas jug while you dump the other into the tank.

That sticker reminds me of a classic sign: ACHTUNG!!! Das machine is nicht fur gefingerpoken und mittengrabben. Ist easy schnappen der springenwerk, blowenfusen und corkenpoppen mit spitzensparken. Ist nicht fur gewerken by das dummkopfen. Das rubbernecken sightseeren keepen hands in das pockets. Relaxen und vatch das blinkenlights!!!

Siteunseen's list is a good one. I think you can assume this car has MULTIPLE issues that affect how the engine runs. I think you would be doing yourself a disservice to approach your engine's issues as though they came from a single cause. The best approach with an engine like yours is a shotgun approach: Go through the thing from one end to the other, checking and verifying everything, cleaning or replacing where necessary. Just assume everything is bad until you can verify it good. These engines are actually rather simple by today's standards, so it will take less time going through all the potential trouble spots than picking away at them one by one, hoping that you will find THE reason your engine isn't running right. (Again, I can almost promise you there is no "THE" reason. There are multiple reasons, after this many years of neglect.) I would add to site's list the following: -- Download a free copy of the official Nissan Factory Service Manual for your year/model of car from xenons30.com. It is the most authoritative source of info on your car, and it's actually a very good manual. And if you hate electronic manuals like I do, buy a paper copy off of Amazon or ebay. -- Replace every vacuum line. Don't just inspect them; replace them. Don't forget the HVAC control vacuum lines. You may need to correct some incorrectly configured lines, so check the FSM to ensure you're doing it right. -- Check your "accordion" boots (especially the one between the AFM and throttle body) for cracks. Be sure to check the underside. Cracks let through unmetered air, resulting in lean running. -- Check your brake power booster for vacuum leakage. -- Search for the "yogurt cup test" on this forum to find a procedure for checking for any vacuum leaks you might have missed. The intake manifold interface with the head is a common leak point, due to broken studs at #1 and #6 and gasket erosion. If you've got a leaky intake gasket, obviously pull the intake/exhaust manifolds and replace the gasket (shared between intake and exhaust). -- Renew, refresh, and probably replace every engine electrical connector. You can get new connectors on ebay. Don't forget to clean up the injector drop resistor connections (beneath brake MC). -- Remove your distributor cap, and rotate the breaker plate. If it sticks and binds, either fix or replace the distributor. -- Replace ignition parts: distributor cap, rotor, wires (use NGK), and plugs (also use NGK). -- After you've addressed these "shotgun" items, run the engine for a while with fresh plugs, and then read them. Do they all read about the same? If not, you may have injector issues (e.g. clogged). -- After you're done, the engine may still be running lean, due to old age issues with the ECU. There's a remedy for that, but let's only discuss that after you've verified all the other stuff.

Captain, it appears you and I have similar interests in tourism! LV does have some interesting things around. Adding a few more obscure or distant things to your list: If you're seeing the Grand Canyon, you might also enjoy Lake Powell. (I've never been.) Extreme low water levels have apparently revealed some stunning formations. In the general direction of California, I fondly remember seeing... The Tehachapi wind farms (You can get a GREAT personal tour by a real engineer who will patiently answer all of your most technical questions. Best tour of anything I've ever had!) The Ivanpah solar farm (Engineers will tour you there, too, but in tiny groups, answering fewer questions.) The Mojave Airport. I don't think there are any tours, but you can look through the chain link fences at an ENORMOUS airplane graveyard. I also remember peering at experimental goings-on with SpaceX before I ever had any notion who they were or what they were doing. The Joshua Tree National Forest. Extreme heat and drought from climate change are starting to kill off the Joshua trees. You might want to see them while you can. I'm sure there are other things of interest in that part of the world. However, when were were blowing through there on a schedule, with a big camper loaded with furniture, destined for LA, that's about all we could take in.