Zed Head

I would replace the rail gauge with the new gauge first. I think that your gauge is bad. A quick swap will at least confirm that you have a problem. The gauge before the filter would show if you had a clogged filter (big pressure drop), but the FPR should still take pressure to 36-37 psi with no vacuum hose connected. A clogged filter would just make things take longer but pressure would still get there. The fact that the vacuum hose causes an 8 psi change is normal, the starting point is just off. 36-37 (no vacuum hose) and 28-29 (vacuum hose) psi will be what a good gauge will probably show. Your fuel supply is probably fine and your problem cause is somewhere else. Again, sorry for the bad advice, I just assumed that the pressure numbers reported were good. Should have asked, since I have three gauges of my own that I swap around to the various devices that use them, just to be sure they're all working correctly, because a bad gauge screwed me up for a few months on a bad FPR.

Backfilling with a realization - the Standard brand FJ3 injector has the "normal" pintle valve nozzle. Only the FJ707T has the odd-looking nozzle. Weirdly, the more expensive BWD injector has the odd-looking nozzle, BWD 57519P - Fuel Injector | O'Reilly Auto Parts, and the cheaper one has the usual type, BWD 27519 - Fuel Injector - MFI | O'Reilly Auto Parts In case it matters... Here's another, from Autozone, that appears to have the odd nozzle. It's the only one they sell. Different brand, GP Sorensen. http://www.autozone.com/autozone/parts/GP-Sorensen-Fuel-Injector/1978-Nissan-Datsun-280Z/_/N-ivfvlZ8vd08?itemIdentifier=79726_2390_0_

Many other old car nuts use the GM HEI module in place of their more expensive or outdated ignition modules. If you search the web you'll find a lot to read, and there are a few threads on this forum that describe it's use with the 280Z's. It was developed at about the same time as the ZX module though and has about the same capabilities as far as I can tell. They're both "smart" modules that control current to avoid system overheating. Actually, the 1978 ignition module was also pretty modern, I believe, it did not use a ballast and point gap was specified at ~.040", which is the typical high energy ignition setting. The main advantage of the GM over the 78 Z and the ZX modules is cost, since it is a widely used part. ~$20 versus ~$100 or more. Those three are probably about the same performance-wise. I get the impression though that the ZX distributor with its six point pickup, might be more precise than the Z distributor. There might be other advantages there also. Check by your fusebox. You might have your original 1978 module in place, ready to be re-used.

The stock 280Z modules seem to last about 35 years, and ~100 - 200K miles. So do the ZX modules, change 35 to 30. The GM HEI module is a cheap, reliable alternative. 123ignition has a module in a programmable distributor that apparently is reliable (based on reports from users of the other cars it's used in). What car are you working with, what distributor are you using to drive the MSD (points or reluctor) and how much are you willing to change? The MSD is one of the few external modules designed to be a "bolt-on, wire-in" system. Others, like Crane, work the same way but they appear to use the same general design as MSD. Might even be the same product under a different name. Lots of options. Many will require a distributor change though. Your heat problem might just show a need for a different location for the MSD module.

Actually, I am running now with the pot either completely open (knob stopped out) or a slight resistance. The tension on the knob is high, it's vibration resistant. And the pot is behind the hood release handle in the cabin, so ranges from 60 - 80 F probably. The changes are from outside the pot, I believe, either fuel or 1970's components. Always ready for a new experiment though. Interested to see what happens.

Curious as to what your plan is. Maybe some small adjustable pots in place of resistors, for tuning purposes? I have a 5K taper potentiometer in my car and it is a little touchy, but I've also noticed that the performance seems to change occasionally for no obvious reason. Maybe with tanks of fuel, but hard to tell. I drive my car almost every day and can go a tank or two with out touching the knob, but occasionally I have to add a little fuel to cover a lean spot, or reduce it to change the smell of the exhaust. Who knows, it might also be ECU temperature itself causing some drift, but something is going on.

You've given some good details but not the big picture. Is this car new to you, maybe just arrived, sitting in the driveway and you're trying to get it running? It's never run right for you, or you've had it for a while and this is a new problem? It could be flooding due to coolant temperature sensor circuit problems. When it's cold, the extra fuel is good for starting. Then it runs for a little while until the engine is too hot to use the fuel. Then there's too much fuel on the restart since the engine is warm. There are some tricks that you could probably try with your fuel pump relay, or pinching the fuel supply line, but the best thing to do is the standard advice of "get the FSM and a meter and do some testing". If you have a meter and download the manual, many people here can run you through the circuits to test. IT's not that hard and you'll learn a lot. Test before starting after the two day wait, then test when it won't restart. Something will show up. Unfortunately, the parts are so inter-connected that it's easy to get mis-led. It's rare that someone's first guess is the right one. Fuel pressure testing is also important. FPR's have been known to be affected by heat.

I would go all the way and put a bench seat and column shifter in there. Then you can cruise with an arm free for your passenger. Haha. The residual hoses attached to the radiator imply that it's the stock radiator unless someone was getting fancy with oil cooling. Looks like it was a factory auto car. The typical mod for autos were called "shift kits". I searched the Google and found a few links. Shift kits for auto Zeds Technical Information Page ..... Transmission Jatco Valve Body Shift Kit Installation 3N71B & 4N71B Datsun 240Z VL Turbo - DragTimes.com

Is this a car sitting in the driveway running for a few minutes, or are you driving it around then turning it off? Are there high RPM involved? The ECU's have been known to go bad, though it's not common, and typically die by dumping too much fuel. Either cracked solder joints, or bad injector transistors.

Look at the shift linkage in the Craig's List ad. It's different than later transmissions. People called it "monkey motion" because it felt different when shifting, apparently. I've never tried one. Probably not what you really wanted anyway. Looks like you ended up at the right place. A free 4 speed just for shipping. Can't beat that.

I think that the OP wants a "monkey motion" 4 speed.

The third wire is for the second pickup in the distributor. There's a whole separate circuit in the ignition module to advance the timing when cold. Lots of engineering and work for a small thing that they got rid of later. I just realized that I could have used those wires and junction box for my injector cooling fan and my coolant circuit potentiometer. Three wires in the harness, running from the engine bay to the cabin. Pretty handy.

The Bosch injectors use different part numbers for the same injector based on hose length and shape. These 0280150105's are the same as 0280150116, except for hose length. Not mine, just posting for anyone that might be using the 116's and looking for spares. It's a cheap price. 5 Bosch Fuel Injectors ERC3620 Part 0280150105 New in The Box | eBay

Here's that list I was thinking of. cygnusx1 posts it every now and then on various forums. Post #26, although the whole thread is generally relevant to what you're thinking of. http://www.classiczcars.com/forums/fuel-injection-s30/44688-280z-fuel-injection-good-system.html

It's not really clear what causes the "lean mixture" problem. Electronic component drift or a system tuned to 1970's gasoline have been suggested. But the coolant circuit resistance mod seems to work to get back to normal. That seems to be the "fix", it's just a question of where you put the resistance. The ECU is very primitive so the best fix you could probably come up with would be a smaller resistor on the coolant circuit, inside the metal ECU box. Same solution, just a different appearance. There is a list out there of what the various components inside the ECU do. I think that the coolant sensor is one. So once you knew the resistance change you needed to make it might be fairly simple to swap a resistor. I could probably dig up the thread.

Any chance you could take a look at the bottom edge of the cylinder? Still curious about what caused the rod to punch a hole in the block.

Did you swap a manual for a manual? So the old pilot bushing is still installed? Might not be a huge problem, but the nose of the mainshaft on the old transmission will give a clue. If it's dry and worn then the pilot bushing probably is too. If it's smooth and lubricated the old one might be okay. That bearing noise is pretty common. The bearings used are generally loose (C3) and noisy. People have reported doing lots of work to quiet things down only to have the noise come back almost immediately with brand new bearings. The noise might be more apparent now that you're hyper-sensitive to transmission problems. Every transmission I've had in my car (four total) makes that noise that goes away when the clutch is disengaged.

Just another update for those with The Problem. I haven't had a single hot start issue since that one weird episode mentioned above (somewhere). We've had some hot weather here and I drive my car almost every day, multiple trips. It's great to finally have a normal car that I can get in and out of without turning on timers or waiting for the engine to settle down after starting. Still hoping for more feedback from anyone using the FJ707 or FJ3 injectors, with stock exhaust manifolds.

I've had the clicking under the dash and it was the fuel pump relay being kicked on and off by the AFM switch. I believe that I removed the clicking by adjusting the metal arm in the AFM to where the AFM vane could close farther before hitting the switch. But the low RPM on closing the throttle still happens, when the engine is between cold and fully hot. I found that the RPM drop got worse as I advanced my timing set point, and since I removed the other pickup coil that kept timing advanced while cold (that's contradictory but idle speed has to be reduced after advancing the static timing, the second pickup coil was for cold engine only, run off of a temperature switch). At this point I just live with it during warm up, since the engine doesn't die and it's only there for a few minutes. After the engine gets warm the issue goes away. The dash pot adjustment helped, but it lasts for longer than the dash pot can stay up. It still bobbles around at ~600 RPM for a second, when the engine is cold and the AAR has closed before rising to 900-1000. It's a weird thing, I think it might have to do with cold air and fuel. Maybe the cold enrichment formula in the ECU is off or, the 10% ethanol in the gasoline is screwing things up. Newer cars control idle speed via the ECU by changing timing and/or an idle air control valve (edit - actually called an idle air adjusting (IAA) unit. Idle air control is our AAR. Browsing my other car's manual).

Most are sealed bearings, I believe, and pre-lubed. But who knows, you could get a dry one. Another test that you could do is to push the slave cylinder rod in and disconnect it from the clutch fork completely. Then, with the engine running you can push the clutch fork back and forth by hand to see what effect it has on the noise. You'll be able to get it completely off of the bearing face, and also apply pressure. You'll be able to feel what's happening also through the fork. Here's a video I found about TOB noise. I don't really like his explanation of the fix though, it doesn't make sense. And here's a general description of a company's bearing. Pre-lubed. Hays Throwout Bearings - Free Shipping on All Orders @ JEGS

That mount or adapter is the piece that 123 USA (probably ED0 had designed and manufactured to make the 123 distributor a bolt-in piece. Prior to that, not too long ago, they suggested that people build their own. Ed probably got a minus tolerance, or worn, shaft to use for his dimensioning and they made a bunch of minus tolerance pieces.

I believe that the push toward using ethanol in gas really started when the US was trying to gain oil independence since we weren't developing oil supply here. That's also the reason behind the new oil fields in North Dakota and the shale-oil and the fracking. The corn lobby is just one of several trying to gain advantage in the situation, and added some lies like many PAC's do, about how it's a natural product and good for the environment and carbon-neutral. The government institutions have no reason to debunk the BS since it helps their efforts to be more energy independent. That video is amusing but the idea that "grit" is transferred from the corn that the ethanol is produced from is nonsense (no offense to anyone that thought it sounded reasonable). The ethanol is distilled, no solid material comes along for the ride. If it did, you'd find grit in your bourbon. And burning ethanol-containing gasoline on a table, under no compression is not representative of inside an engine. Anyone with an old car or engine is kind of screwed since the government's decisions are based on what's good for the masses. I'm not saying it doesn't screw up old engines, only that there's a lot of nonsense out there. The nonsense is great for the borderline repair shop as a tool to explain why you need to replace a bunch of parts on your engine. The more confusing, the better.

It's the thing that holds the big ball bearing, under the filter. Image of it removed, way below. BUT, your problem might be in the filter itself. Anti-Drainback Valve. Some oil filter mountings may allow oil to drain out of the filter through the oil pump when the engine is stopped. When the engine is next started, oil must refill the filter before full oil pressure reaches the engine. The anti-drainback valve, included in the filter when required, prevents oil from draining out of the filter. This anti-drainback valve is actually a rubber flap that covers the inside of the inlet holes of the filter. When the oil pump starts pumping oil, the pressure will unseat the flap. The purpose of this valve is to keep the oil filter filled at all times, so when the engine is started there will be an almost instantaneous supply of oil to the engine. FAQs| FRAM Datsun 240Z Oil Pressure Relief Valve, 260Z 280Z 280ZX

I've never considered the failure mechanism for a "thrown" rod but it looks like the wrist pin breaks free from the piston, leaving the piston pieces in the bore, then the rod is smashed through the side of the block by the crankshaft on the next up stroke. Is there any damage to the skirts at the bottom of the bore? It seems like that would be the fulcrum, or ramp, to redirect the rod sideways. If the rod came off the big end first it seems like it would just get pounded up the bore and stay there with the piston. That's why I thought that there would be head damage.

Sorry for the bad advice. If you had a pile of spare parts like I do you could have double-checked the FPR. Thinking back, people have had cases where something loose in the tank covers up the screen on the outlet port of the tank. Either rust particles or gas tank sealer or just junk that ended up in the tank. Then when the pump turns off it floats away, and the cycle starts over. I would let the pump run on battery power in the garage, without the engine running, and just listen. You'll hear a change in pitch from the pump if there's something happening back there. Then crawl underneath and run a line to an external tank. Do the same thing. If the pump runs fine for extended time on the external tank, but not the car's tank, you'll know where the problem is. Forgot to say - make sure your gauge is good. They go bad. #5 and #6 here - http://www.classiczcars.com/forums/fuel-injection-s30/52413-78-no-start-w-out-fuel-priming.html#post457924