Zed Head

Just found another reference to hot-start from the 1981 280ZX Turbo review. Surprised I didn't catch these before, I've borwsed through most f the articles. This one is with the cooling fan. From May 1981. Note that they didn't report actually hearing the fan run. "we found that cold starting and driveability were very good but the the engine wasn't overly eager to start following a hot soak, and ran tentatively for several seconds before clearing out. An auxiliary cooling fan actuated by coolant temperature and positioned to blow cool air over the fuel rails is supposed to minimize the problem, but it obviously isn't a cure-all for every hot-soak condition."

Thanks FW. I think I know where it is now. Found another drawing in the FSM. I'm pretty sure I've checked the check valve function from the engine bay in the past. It seemed to have a one way action and I thought I knew what I was looking for, although, looking at the drawings, it's not clear to me what it's actually designed to be checking. But I get no whoosh at all. Might have a slow leak down to the charcoal canister. Redwing, it could be that somebody removed your charcoal canister and blocked the vent line. The canister is about the size of a gallon coffee can and sits right next to the radiator, passenger side. It's black and has three small hoses connected to the cap on top.

I think that it should work fine. You could even mix and match AFM and ECU, I believe. I have an assortment of ECU's and AFM's, from 75 to 78, that I have run together in various configurations. No significant differences, besides small effects of age and wear and tear. Wasn't it you that had the altitude correction on your car? You might lose that if the 75 ECU doesn't have it. But you could still run the AFM. And the ECU would work it just wouldn't do anything with the altitude switch. If the price is reasonable and the parts are in good shape you might buy it just for spares. I was just looking at my new MSA AFM that I bought five years ago but haven't really used much and it's already showing a good amount of wear. I don't think the reman parts are anywhere near as durable as original Nissan parts. A 100,000 mile Nissan AFM might have another 150,000 miles in it, while a reman AFM might last 50,000 only. Mass manufacturing has its benefits.

I think that the later 4 speed, and 5 speed bolts might be the same. carpartsmanual shows the same part numbers, just different quantities. Weird. I just used my 4 speed bolts on all of my 5 speeds. Seemed to have plenty of thread engagement. Looks like the very early 4 speed had one bolt different from the later 4 and 5 speeds. Also, I think that the bolts are still available from the dealer. $1.12 each at courtesy. A good parts guy could find them on the microfiche. Of course, if you're not looking for the parts, just the specs. this may not help. http://www.carpartsmanual.com/datsuns30/DatsunFairladyZIndex/PowerTrain/TransmissionCase/5Speed/tabid/1702/Default.aspx http://www.carpartsmanual.com/datsuns30/DatsunZIndex/PowerTrain/TransmissionCase/4Speed/FromSep-71/tabid/1701/Default.aspx

Pretty sure that EuroDat knows. I think that he made a list. You might find it with a search. Or a PM.

This guy seems to be the most popular for finished complete rails for the L6 engine. He offers a variety of fittings from 11mm to barbed, along with a gauge fitting if wanted. Check the last few posts to see how to order. http://forums.hybridz.org/topic/99098-pallnet-fuel-rails/ And a few of us have made our own. You can get stock from Ross Machine Racing on eBay. If you're not worried about finish sometimes he sells dinged stock for a discount. http://stores.ebay.com/Ross-Machine-Racing

It definitely helped. I had it on a 20 minute timer and if I turned it on I had no problems when I came back, if I forgot and came back in the critical window, it always had the problem. But I had a hose with holes directly over the injectors to direct the air right at them. Then I added an aluminum fuel rail with different injectors and solved the problem completely (I thought) so I removed the fan. Adding others' experiences in to the mix suggests that the larger fuel volume and the better heat transfer of the aluminum rail keeps the injectors cool. Fastwoman suggested heat-pipe technology as a reference, like distillation but for the purpose of removing heat. Things were fine unit just this winter when the problem came back, probably due to fuel changes. So I added insulators to the injectors and it dropped it to about a 2% level. Occasionally, after a long drive and a stop I'll get a second of roughness. But it goes right away. Everything points to hot injectors.

I think that the CHTS hole is dry. On the ZX distributor - some, the later ones, came with an E12-92 or -93 module that has an electrical timing advance connection. It can cause problems sometimes, apparently. The E12-80 only has one external connector, with two pins, and the reluctor connections on the inside. You can swap the modules, or there's a method to lock the advance connection into one state by applying power to it.

I looked for it in the FSM but didn't see it referenced anywhere. From what I've read, most people that have the fan have never actually heard it run. The switch is set for 210 degrees or somewhere close to that, apparently, and it's mounted in the thermostat housing. I mounted a ZX fan on my car, with a manual switch, and they're pretty noisy so you'd know if it was on.

Where is the check valve located? I see that it's in the vent line, but haven't seen its actual place on the car. I've never had my side panels off to look at the reservoir and lines above the tank. Afraid I'll crack the panels getting them out.

I have a book that compiles all of the Road & Track tests of the Z cars over the years. Found an interesting comment in a test of the 1979 280ZX from April 1979, compared to three other sports cars. "And we found that after a brisk workout, it would sputter and spit back through the injection on restart." Think they meant intake, not injection. So it looks like the hot-start problem has always been there, even with ethanol-free fuel. Just a consequence of placing the injectors next to the hot exhaust manifold. The R&T guys probably got things pretty hot so there would be a lot of excess heat in the block and manifolds.

Are these big bumpers or small bumpers?

"Ripped off" is in the mind of the buyer. I'll guess $3000. Never mind, Nada and Kelly apparently don't even do old cars any more. Try Hemming - http://www.hemmings.com/priceguide/ Notice the difference between 70 and 71. 70 is a collector car, 71 is just a 240Z. No offense to any post-70 owners.

There are two engine pictures there now. I see one potential problem right off the bat. The wires to the battery. Probably not the cause of the engine problem but they look bad. I assume it's the negative terminal although I can't be sure. That exposed junction probably would have shorted by now if it's the positive. But usually it's the positive that corrodes like that. The PCV hose from crankcase look unusual also but maybe that's the rerouting that Nissan retrofitted in 1977. It looks like the original hose connection is plugged. The battery connection alone suggests that the engine has not been maintained at the highest level. So there's hope that the cause of the problem is a simple one. Isn't it tic-tac-doh!..?

This will make things difficult but not impossible. We all, out here, tend to forget where we started. I worked on cars all through high school and many years after before taking a break and buying a new car. When I came back to it, even I took some time to get back up to speed. Here is a simple thing to look for that might help determine if you have a fuel problem (clogged lines or bad fuel pump or bad fuel pump power circuit), versus a bad ignition system. As you're driving down the road, if the engine dies, leave the car in gear and watch the tachometer needle. If the needle drops directly to zero even though the engine is turning over, that's a sign of an ignition problem. If the tachometer needle still shows RPM but the engine is obviously not running, that's a sign of good ignition but no fuel. I don't know if the engine turns fast enough to make the needle move during starting but it might, So if you end up dead on the road, watch the needle while trying to restart. If it moves with the engine turning over, you probably have spark. Of course you'll still need someone to work on it, but at least you'll have a better idea of what it needs. You might also consider letting the engine run in the driveway and seeing if it dies eventually. If it does, you can do some detective work within walking distance of your home. It will cost you some fuel but won't hurt anything.

That is not correct. It's one of those things an "almost there" mechanic might screw up for you. There are two temperature units, one for the ECU and one for the gauge. The engine can run fine without a gauge and can indicate temperature just fine but have a problem with the fuel mixture due to a bad sensor. Two totally separate issues. One thing that any decent mechanic could do for you is to put a fuel pressure gauge on your fuel rail, between the filter and the injectors. If they could mount it where you can see it while driving you'd be able to see if you're losing fuel pressure. You'll have to drive with the hood partially open so the gauge can hang out but you'll know something very important. Since the problem is happening frequently now, it should only take a short while to see if it's fuel or ignition.

Those lines run to your Auxiliary Air Regulator (AAR) mounting block, and,probably, the EGR system. You could get a T fitting to put in to the hose for the return line. I think the hose size is 5/8". I posted a picture but the size is wrong so don't buy that one. An auto parts store will usually have a selection of sizes.

The liquid could just be spray from a bad hose fitting. Might just take that hose off and smooth the hose nipple. They tend to get cruddy and corroded. Pictures before cleaning are best.

Like a NOS setup except the pssst, psssst is for cooling, not clearing the NOS lines? All the kids would think you want to race. The scary thing about rapid cooling of hot parts is that they tend to distort and sometimes break. I had a cooling air setup on my injectors for a while, with a hose with holes in it to direct air on to each injector. It worked great but I had to twist a timer dial every time I stopped the engine. Keeping them cool, instead of cooling them after they got hot. A turbo timer would probably work. It was a lot of complexity though. The aluminum fuel rail and the insulation of the injectors seems simpler. A timer on the fuel pump do the trick. Keep the cool fuel running through the rail. I had pondered that but never tried it. Leaving the fuel pump running with the car unattended bothered me, plus heating the fuel in the tank. I also thought about running a line from the coolant system over the injectors with an electric water pump, but air was easier. The situation is just aggravating, overall.

Probably a ground wire and the condenser body. Don't let any well-meaning person start tweaking and adjusting things to try and get it to start. If it ran well before, and now you just have a no-start problem, the solution is probably a simple one, like an ignition module, or bad battery. A picture of the wires and your engine bay would help a lot. And keeping everything in one thread. This thread, for example, doesn't have the description of the car dying and not starting. But the other thread does.

Ideally, your struts have been cut to give the desired ratio of compression travel, to extension travel. That's the main goal of the strut sectioning. John Coffey posted some numbers a little while ago, somewhere. Can't remember it but I'd guess it's like a 2:1 ratio. So if you have 6" total, you'd look for 4" compression, 2" extension. On the springs, I've looked at spring extenders myself. They're basically spring perch elevators. Molded plastic pieces designed to fit the spring shape and sit in the perch to lift the spring. I found some but they were more than I wanted to spend. I'll probably fabricate some, eventually, just to get another 1/2 inch. They are out there though.

Aside from engine mechanical issues, 1976 comes with EFI, unless somebody swapped carbs on to your engine. It really could be a project if you don't find someone who knows the system. It's fairly simple but has it quirks. A mechanic who isn't familiar can really make a mess of things. Once they're dialed in they're very dependable, on a daily basis. But when they have a problem they can be a nightmare.

Good point on the spark plug well leak. I didn't think that one through. Another possibility case is a cracked head. Hopefully not. My gas cap doesn't whoosh, and the system seems to work fine. Could be that my check valve is weak though. Copied a picture just to show all of the parts of the system.

I second SteveJ's recommendation. You need to find a mechanic that knows how to work on these old cars. There aren't many out there. Both siteunseen and madkaw know what they're doing and still feel uncomfortable with their mechanics. The trouble starting when hot could be the common "hot start" problem. The "whoosh" could be a modified tank venting system (some people don't understand that the charcoal canister in the engine bay is important no matter how ugly it looks). The leaking "main motor gasket", actually called a head-gasket, is not uncommon after many miles. My 76 engine had a leaking head-gasket. The head was also warped, but in the opposite direction of the leak. That's an example of a how a small job, gasket replacement, turns in to a big one - a head rebuild Unfortunately, many well-meaning mechanics will spend a lot of your money and time before admitting that they don't know how to work on the old L6 and its EFI system. Find that local club. Southeastern USA covers a lot of territory, more details could lead to more suggestions.

A spare engine I picked up had had water in the fuel and it rusted the inside of the fuel rail. The filters on the injectors are only meant as a last resort, thy can clog easily. On powering the injectors for cleaning or testing - I run six on a fuel rail with power from the battery in series. This gives about 15 ohms of resistance and keeps the current flow down. It's the current that would overheat them, they're made for 12 volts. For precise characterization though, a PWM would be the way to go. For comparing wide open flow rates to see if they're clogged, just turn on the power and fill six containers. I've seen up to 20% deficiency in flow rate this way, with old crummy injectors. You could either add resistance singly or rewire all six at once. Be careful with vaporized fuel and sparks though. Once you see an injector spraying well, out in the open, it makes you nervous. Edit - somehow I got a funky font, WTH. And I can't change it in the first sentence, it's locked in.