FastWoman

Sure thing! Glad you got it straightened out.

I'd replace it, as it's not very useful trying to patch rotted materials. I remember when I was a kid in my '75 Z. The guy in front of me didn't notice the green light, so I gave him what I intended to be a short, friendly mini-beep. The horn pad came apart and jammed the horn, which blew continuously, and the pad dropped into my lap. The situation quickly escalated into a minor road rage incident, where the guy dropped back beside me (after we were moving, and as I was desperately looking for a place to pull off), rolled down his window, and started screaming at me. I picked up the horn pad and waved it at him to show him that my horn came apart. He interpreted that as an aggressive gesture and became even angrier. Fortunately he left the situation, disgusted with me. I pulled off and was able to silence the offending horn. Yeah, just replace it. It's a safety item.

Twice I looked at this thread and thought the problem was solved! But since it's not, I'll pitch in too... Let's simplify a bit. Disconnect your (-) battery cable, disconnect the big wire from the B post, and keep it safely out of the way. (Wrap with a bit of electrical tape?) Reconnect your (-) cable, and start your engine. You should get 14.5V from the alternator, give or take. This is your alternator's output when not under load. It should reflect what the integrity of the voltage regulator. Next connect a heavy piece of wire from your B post directly to the (+) terminal of the battery (remembering again to pull the (-) battery cable to do your wiring). Start your engine again. You should still get maybe 14.5V at the B post. If you're still getting 12.5V with that setup, either your alternator isn't putting out adequate current (my guess), or something is wrong with your battery (unlikely). If your alternator and battery work, then the problem is somewhere in your car's wiring. The more likely guess would be a fusible link issue (still), but if that's not it, take a look at the alternator-to-battery wiring. If you unwrap the wiring harness between the alternator and the fusible link assemblies, you'll see a scary mess of funky spliced wires (spliced at the factory). You could beef up those wires and connections. BTW, the alternator and fuel pump do interact on the later models. The alternator output and oil pressure signal feed to the fuel pump control relay to signal that the engine is running. If both of these signals fail, the fuel pump is shut off. Also the 12.5V reading at B and S, compared to the 12V reading at L is normal. B and S have a direct path to the battery, while L has a semiconductor junction inbetween, thus dropping the voltage by about a half volt.

I'm assuming you have a points ignition??? When you turn your ignition on, do you get +12V to the (+) side of the coil? (You should.) If you do, then what happens if you disconnect the wires from the (-) post, connect another loose wire, and then CAREFULLY tap the other end to ground? Do you get a spark then? There's probably a ballast resistor involved somewhere in there too, but I don't know how it's wired. Nevertheless, you can determine if your coil is good by manually tapping a ground wire to the (-) post of the coil. If your coil has +12 to the (+) post and tests good, then your next step is to look at your points. Are the points and condenser new/recent? Are they properly adjusted? That's about all there is to the ignition, at least up to the point of the coil wire.

The thing is, though, the little connector for the voltage ref and alternator fault light melted. I don't think it would have anything to do with the condenser. OK, I'm now looking at an internal schematic of the '78 alternator in the '78 FSM, page EE13. If you were to ground terminal L of a running alternator, you'd have a direct short and would probably melt the connector. I'd check there.

Steve, actually the wire of the noise suppression capacitor (condenser) would be +12 and connected to the output post. The body or can of the capacitor would be ground and would be connected/bolted to the alternator. I had looked at this thread earlier, and I haven't a clue either. Ordinarily both of the smaller wires would be fed 12V. One is the voltage reference line, and the other is the alternator fault light line. The fault line is grounded when there's a fault with the alternator, thus grounding the fault light in the dash. (The other side of the light goes to +12). Is it possible there's an alternator fault AND the fault light is miswired? Perhaps you have +12 going directly to the fault line, sans a bulb? Anyway I wonder whether your alternator is still good. What you describe makes no sense otherwise.

Scott, I was going to replace the seals on my quarter windows. I removed the passenger quarter window. The process was VERY easy -- no risk to any of the parts. Upon removing it and seeing how the whole assembly went together, I was satisfied the area was perfectly tight, so I simply put it back together. On a scale of 1-10 in difficulty, it was about a 2 or 3. Spark plug wires and the air filter might be a 1. BTW, the interior panels are very easy to remove. You'll need to pull out your dome light, then remove the panel that fits into, and then remove the quarter window trim. To release a plastic rivet, simply push the little black rod through the rivet with a small nail or paperclip. It will fall harmlessly into the body cavity. Then you can pull the rivet out. If you're lucky, you can find the little rod again, so that you can reuse it. Otherwise you can order new rivets.

Hannah, I think what Steve is saying is that you should first search the archives for an answer and, if still clueless, post a question in a new thread. FAIW, I'm not sure what you mean by a "diverter valve." On the fuel injection style pumps there's an internal bypass valve and an external check valve. I don't know the anatomy of the pumps for carbureted models. Anyway you might search for either of those terms. Obviously when you do post, it would help greatly if you could tell us a bit about your car, as there's a world of difference between a 240Z and a 280Z, and there are even important differences between the years. Anyway, welcome to the forum!

Jenny, the screw tightens down on a tiny plate that has a dimple in it to grip the clock spring wheel. I think it's that dimple that makes the semispherical dent, at least when it's been tightened down in the same place for decades. My AFM was also a bit loose per the Atlantic specs, so I tightened it a bit. It's possible the Atlantic spring tension specs are off. They are based on measurements on two used AFMs that were believed to be unmolested. Both AFMs agreed with each other, but it's still a small sample. You have two good choices for the resistor. One is to put a fixed resistor in the wiring harness where you suggested. The other is to put your variable resistor inside the cabin of the car. However, I wouldn't put a variable resistor under the hood, unless it's designed to be exposed to those harsh conditions. It's very easy to put the variable resistor in series with the #13 wire to your ECU connector. You'll have to unwrap a bit of the harness and then wrap it back up (with electrical tape). It's no big deal. If you do it that way, you can readjust the thing later as needed.

@argneist: Cool! I think you're really going about this the right way! @jimslaton: FAIW, my '78 tank was in pretty nice shape, and I didn't do anything more to the inside than pressure wash and rinse it out. In truth, it probably didn't need even that. However, it was probably time to replace all my hoses (which I did), and I did have a pin-hole leak on one of the fittings on my fuel/air separator. So my pulling the tank wasn't for naught. Besides that, I had a chance to repaint my tank and clean up the underside of the car above the tank.

Yeah, I do mine just like Zs said, except with the sparkplugs removed. A bungie cord is great for holding the throttle open.

Jenny, you won't need much wire. Just try soldering a joint. I'm sure you'll say, "Oh, gee, wow, that's easy! I don't know what I was ever fretting about." If I were you, I wouldn't try changing the resistances in the AFM. The CTS circuit resistance will compensate for any out-of-range resistances in the AFM, as long as you get smooth, graded responses from the potentiometer. I get that you don't want to hook up power to the thing, but there's another way. Get an old-style meter (with a needle), and simply measure the resistance between terminals 6 and 7. Don't worry about what the resistances are. Just move the flap smoothly back and forth throughout its range, and make certain the multimeter needle moves smoothly and doesn't jump and skip. That's all. Nothing fancy. If it passes that test, just make certain the spring tension is stock, and put it back on. Regarding your spherical notch: I have one too. It's just a depression made throughout the years by the pressure of the set screw. Anyway, get everything back together, find a potentiometer like I linked to (above), solder up some wires that will get you a safe distance away from the fan belts, plug the thing into the CTS connector, and see what CTS resistance your engine "wants" when it's warmed up. ------------ PS I just upgraded my machine! No, not a laptop. Laptops aren't very useful for photoediting.

Ron, wow, I'm a photographer and I didn't even think of that! Good idea!

Sounds like your motor is pretty worn to only get 90 psi. What are your compression numbers when you squirt a bit of oil in the cylinders?

I am sending to you my most Gracious Greetings, kindest Mr. FixItMan, and I am hoping this important dispatch finds you in the magninimous of excellent constitution! FAIW, some people are tempted to deposit such checks, thinking they will somehow get the best of the scammer. The funds do show up in the account, but they are ultimately reversed, often with a service charge imposed for the counterfeit check. They get people coming and going! May God endow its humble blessings upon yourself.

Was it a backfire (out the intake) or an afterfire (out the exhaust)? If it was a backfire, you might be having fuel starvation issues. Does the engine die very suddenly, or does it sputter briefly before dying? If it was an afterfire, you might have ignition problems. If the engine is running, and the ignition very briefly drops out, the exhaust will fill with raw gas fumes and oxygen. Then when the ignition kicks back in with the engine still spinning, the first load of hot exhaust gas (and flames) ejected into the exhaust will ignite the raw fuel and air.

I wonder whether they somehow neglected to replace the potentiometer board. I'm sure theirs have resistances all within a tight range of each other, and the resistances you reported were quite different from their normal values. Don't worry about the lead. Just don't eat it, OK? Obviously wash your hands after handling it. If I were you, I'd just practice soldering on bits of copper wire. That's better than sacrificing working computer parts. Remember, I suggested practicing on boards when I was suggesting a modification to your potentiometer board. There's no need for that now. You won't need much practice anyway. I bet you'll succeed brilliantly in one try. It's that easy.

Hmmmm.... Well, maybe no, then... The style might be different, but I thought all S30 doors were essentially the same. Might be wrong about that.

1: Righthand side??? Maybe the windshield washer reservoir and pump, although it's on the opposite side on the 280Z (with which I'm familiar). 2: Yes.

Easy: A collection of tools and loaner test equipment. To borrow an item, you have to put up a deposit.

Argneist, you'll be able to see where all the hoses go after you do all your disassembly. You'll need to remove (almost?) all the plastic panels around the hatch area. That will reveal the fuel/air separator tank in the right rear quarterpanel, as well as the vent hoses that loop around the back and exit through the floor. Remove the separator tank, pulling off all the hoses. Then push the vent hoses through their respective holes in the floor of the hatch. Loosen and break loose the rubber filler neck. Remove the metal shield from the lower part of the right rear wheel well. Then unbolt the tank straps, and lower the tank down -- probably with some help from above to feed the filler neck through the hole. You'll be able to see and replace each and every hose.

Wow, I've never heard of that playing out! I'll never slip a hose in a gas tank again! Why not just pull the sending unit out to clear your tangle? It's a lot easier than dropping the tank. FAIW, the easiest way to drain your tank is to remove the plug at the bottom.

Seemed that way at the time!

Ah, geez! That happened to my mom in Laredo -- a nice late-model Cressida that she had entrusted to a valet parking garage. She never got it back. I hope you have better luck.

Oh yeah! I forgot too! OK, you're good. I think you've got the valves on your list (which is a satisfying, non-stressful thing, I promise). Put your best non-rebuilt AFM on, get your CTS screwed in, go to Radio Shack for parts, and you'll be good to go. Here, get these. You can even mail order them: http://www.radioshack.com/product/index.jsp?productId=2062308 http://www.radioshack.com/product/index.jsp?productId=2062758 Optionally: http://www.radioshack.com/product/index.jsp?productId=2062715 http://www.radioshack.com/product/index.jsp?productId=2049747 http://www.radioshack.com/product/index.jsp?productId=2104090&clickid=prod_cs Watch this (or any number of other videos): While you're at it, also order this, so that you can test the potentiometer in your AFM: http://www.radioshack.com/product/index.jsp?productId=2999093# The reason you need a needle is that you can see it twitch if you have a dirty electrical contact. You can't see a digital display twitch. Let's get your car running!