FastWoman

FAIW, the local carburetor guru swears by Sta-Bil. He deals with ethanol damage everyday. My own personal approach is just to burn it up, use it up, or drain it. I sometimes use stabilizers, but only sometimes.

I doubt you're hearing the injectors spraying fuel. You might be hearing fuel rush through the lines. I suspect Steve is right, even though he doesn't think he is -- perhaps if your description is a bit off. When you turn the key to "start," the fuel pump will operate for 5 sec, IIRC. Then it will stop if there's not either oil pressure or alternator voltage. So if that 5 sec is needed to re-charge your fuel rail, I suspect the fuel is leaking down. You can test this by putting a fuel pressure gauge on the fuel rail, probably between the output of the fuel filter and the inlet to the rail. Pressure should hold for at least an hour, practically speaking. If it doesn't, your injectors (including cold start) might be dribbling fuel, or the check valve on your fuel pump might be letting fuel wash back. Once you get air in the fuel rail (from a bad injector dribble problem), it can take several moments of engine running to eject it, as the bifurcated fuel path can prevent the air bubble from being "burped" out the return line. (The bubble has to be consumed through the injectors on one side of the rail.) The solution is to replace injectors and replace the check valve. Another solution that I used is to install a momentary switch (e.g. pushbutton) that feeds +12V to the coil of the fuel pump relay. You can use this switch to prime the fuel rail prior to starting. Now that I've replaced the working components of my EFI, I no longer need to use my primer switch, but I'm still in the habit. I think it makes the start a bit faster.

Eric, the air temp sensor is actually a thermister. The spec resistance values are shown on EF-31 of the FSM. At 68F, it should read 2.25 - 2.75 kOhm. Resistance should go up as temp decreases (e.g. 7.6 - 10.8 kOhm at 15F) and down as temp increases.

If your engine is misfiring, then readings of almost any sort can be misleading. My engine was running EXTREMELY lean and misfiring because of it. As a result, my plugs appeared somewhat sooty, falsely indicating a rich running condition. I would think any misfiring could throw extra O2 into the exhaust and fake out an O2 sensor to read lean, even if the mix isn't lean. (I might be wrong about that.) I would think you need to be hitting reliably on all 6 cylinders for lean/rich metrics to mean much. Dunno. Perhaps the easiest/best way is to experiment to see what your engine "likes." You can pop the cover of your AFM and manually move the vane farther open or closed. Figure out whether your engine wants more fuel (opening the vane). If so, then it's running lean. If the opposite is true, it's running rich. Once you get your engine firing reliably on all 6, then the methods suggested above would probably be more meaningful.

If your volt meter is reading only 12V with the engine running and the alternator actually spinning, then you either have a bad connection to the alternator, or your alternator is bad. With your engine stopped, measure the voltage at the output post of the alternator. If you get a 12'ish V reading there, then the connection between the alternator and the battery is good. There's also a smaller voltage reference connection that should get 12V. I forget whether the engine needs to run for that. Anyway, alternator tests are quick, easy, and free at most auto parts stores. Your battery is fine, and your voltage regulator is internal to the alternator on a '78. I have no idea about the brake warning light. I would think that would be a separate problem.

all of the tiny holes that the fuel flows through. You probably need to order rebuild kits. Disassemble the carbs, soak the parts in carb cleaner, blow out all the tiny holes with compressed air, and reassemble with the new gaskets, O-rings, etc. Be very careful to put them back together the same way they came apart. Take pictures! Do one at a time, so you have the other for reference.

I would bet it's either bad gas or clogged carburetor passages.

^ +1 The 1977 saltwater-cooled 318 engine on our powerboat has probably sat up every winter for 3+ decades in a brutal, moist, salty environment, with heavy condensation every night. The outside of the motor looks somewhat like a 17th century ship's anchor in its raw state, pulled by divers from the ocean's bottom. I recently did an R&R on the intake manifold, and the valve assembly, push rods, etc. were in amazingly nice, rust-free condition. There was only a touch of surface rust on the #1 exhaust pushrod, where some salt water had dribbled down from the riser over the #1 cylinder. I was truly amazed. After seeing the condition of the internals of that 318, I have nearly zero worries about any other motor that sits up.

Sledge, did you manage to make any progress? Just wondering...

I think you're right, Evil Turkey. The biggest ding I've ever gotten in any car was in my '75 280 right after having it repainted. I think it was put there with a hammer (seriously).

^ yep! Eric and I have some pretty long threads going about these issues. My long and meandering "purs like a kitten" thread chronicles what I did to straighten out my engine. Jenny has a very long thread going about her '76, and she's in the process of doing what Eric and I did. I don't know how new injectors would compare to old injectors. I suppose the old injectors could have deposits in them, but they might also be worn. Whether the end result would be more fuel or less is hard to say. In short, what Eric and I did was to put EVERYTHING right (to spec) with the fuel/intake system and then to correct our lean-running situations by adding resistance to the coolant temperature circuit.

Funny plate, Leonard! I can see how it would be for a niche population, though. I don't think many kids/young men would want to steal it.

Wow, that's a DEAL, Steve!

+1 Idling is hard on an engine and especially the exhaust, counterintuitive though that might be. An occasional drive during the winter is a good thing. It's even better if you do a little bit of hard accelerating (pedal to the metal) after the car warms up. This is different from revving the engine in the driveway.

Argneist, if you build computers, you can work on the Z. The connectors inside computers are much finer and more delicate. Nothing will fall apart, perhaps except for some of the fuel injection connectors in the engine compartment. However, you can easily replace those (see prior link in this thread). I think you'll do fine, once you get over your fear of the car. (It's pretty hard to blow anything up. If you want to be ultra-conservative, just pull the negative cable off the battery whenever you do electrical work. Then it will be near impossible to blow anything up.) The intermittent problem you describe in your last post sounds like classic dirty/corroded/loose electrical connections and/or dirty/corroded switches. Think of it as a rnd() function in your wiring. If you can find a digital fuel gauge with a long cable, go for it. However, there's a lot to be said for just laying the thing in the passenger seat, rather than screwing it to your dash. Personally, though, I really doubt your fuel pump is bad. Usually anything with an electric motor either works, or it quits. There's not much inbetween. If the pump operates correctly in the driveway, it'll almost certainly operate correctly when you're driving. The electrical connections are more likely the culprit (assuming you have fuel pressure problems at all).

Every year is a bit different for the fuel pump circuit. In the '78 (my year), the fuel pump runs with the key in the "start" position and then remains running if there's output from the alternator or oil pressure. If both the alternator goes dead and the oil pressure dies, the pump will shut off. This is controlled by a fuel pump control relay (a different relay from the fuel pump relay). Both relays are located inside the black box on the inside of the passenger side fender in the engine compartment. If the '77 is at all similar, your fuel pump control relay might be out. Earlier models (I don't remember how much earlier) have a fuel pump shutoff switch in the air flow meter that shuts off the pump if airflow drops below a certain rate. You should download a copy of the '77 factory service manual. You can find it free, but I forget where.

If I were you, I'd monitor the voltage right at the fuel pump. Put a ring connector at the end of a long wire, and connect that to the (+) terminal of the fuel pump. Run that into the cockpit, possibly around the back of the car and under the hatch door. Then wire a test light between that wire and some ground point in the cockpit area. Better still, just verify all of the wiring. It's not that hard. FAIW, the AFM has a fuel pump cutoff switch. Some people have trouble with that cutting out at low idle. It takes a bit of adjusting to stop it from happening. Regarding the fuel gauge, you would really do a permanent installation of another instrument just to debug your engine? That doesn't make any sense. There's nothing dangerous about running a fuel hose, especially if you secure it with a few zip ties. (Just be sure to bleed the air out of it, first, though, or your fuel pressure regulation will get sort of sloppy!) If it worries you that much, just pay the $4/ft for the fuel injection grade hose. It will still save you money over the permanent installation of an expensive gauge you don't need.

Well, if you simply need to diagnose a problem possibly relating to fuel pressure while you're driving, you could always run a long fuel hose from that T-fitting, out through your cracked hood, and into your window. If you need to close up the car, just roll up the hose and tuck it back under the hood. Theoretically you should only use fuel injection hose, which is about $4/ft, but I think you could get away with regular fuel hose for maybe $1.60/ft just for the testing. If your fuel pressure cuts out, remember that the problem could be electrical! I suppose you could also run some wire from your fuel pump terminals to a light in the cockpit. If the light flickers or goes out, then you're losing power to your pump. FAIW, there are two very large connectors on the cockpit side of the firewall on the righthand side. The fuel pump supply runs through one of those connectors. Mine was charred and melty (inadequate connector), and my fuel pump kept going out because of failure of that connection. I finally had to snip the wire out of that connector and connect with a bullet connector. Problem solved.

This method works. I've used it on an ancient marine engine with no timing scale or notch (both rusted away): http://atlanticz.ca/zclub/techtips/tdc/index.html I bet you have a notch, but you can't see or feel it because it's filled with dirt/crud/rust. Put the engine to TDC, and hit the crank pulley with sandpaper or a wire brush, and I bet you'll find a notch. Then hit it with a dot of white paint. (Liquid paper also works.)

Maybe a different shade in the same color family? Maybe a maroon?

Argneist, there's not going to be any dedicated fitting for measuring fuel pressure. You'll want to hook a guage to a roughly 5/16" "T" fitting. Disconnect the fuel hose from the output of your fuel filter, and put another tiny length of hose on it (with a clamp). Connect the other end of that length of hose to the "T" fitting (with clamp). Connect the hose that came off of the fuel filter to the "T" fitting (with clamp). The gauge should be connected to the third leg of the "T" fitting (with clamp). Then you're good to go. I personally wouldn't see any use to an in-dash digital fuel pressure gauge. Fuel pressure goes up and down with engine vacuum, so unless you have both gauges going (fuel pressure and engine vacuum) and are very quick with mental mathematics, it's not really going to tell you much. Besides that, dashboard instruments aren't generally used for monitoring and diagnosing conditions that might cause your engine to run poorly. Rather, they are used to warn you that your engine is about to self-destruct somehow or leave you stranded. They're useless if they don't give you forewarning. Even an alternator/voltage gauge gives you forewarning -- to keep driving to the nearest shop, because you won't be able to start your engine after you shut it off. You'll know if your fuel pump goes dead, because your engine will immediately die. A gauge won't help you. As far as dirty connections are concerned, how many 30 year old computers have you seen that still operate? Those usually have soldered and gold plated connections and have probably been stored in not-too-hostile conditions (e.g. in the basement or in a corner of a storage room). By comparison, a car's connections are mostly crimped. They might be tinned, but not gold-plated. The car would have spent much of its life in rather hostile conditions. I'm amazed these electrical systems work at all! I haven't yet cleaned every connector on my own car, but then again it was largely working when I bought it. However, I've meticulously cleaned every connector I've encountered when doing other work, and I've rewired much of the engine compartment (which was the crustiest, most deteriorated part of the system). That said, if I had intermittent electrical problems all over the car, I'd just start pulling connectors and cleaning, without much attention (for now) to debugging. Can't hurt. If you've ever had mysterious problems in a computer, you might have been advised to re-seat all the connections -- pulling and replacing each card, each memory board, each ribbon cable, etc. It's pretty much the same approach.

Jenny, yes, you can lose the clips, and I doubt you can buy replacements, but you can make them easily enough -- probably just bending them from small paperclips. Andrew, you wouldn't believe just how badly my connectors were coming apart! In fact one of my fuel injector connectors completely crumbled between my fingers. Yikes! Argneist, if you're having lots of electrical issues everywhere, it certainly wouldn't hurt to undo every connector, clean, grease, and reassemble. It would be a bit of a project, but from the sound of it, I think it would be well worthwhile. Don't forget to undo your ground connections, clean/sand the metal, and reconnect -- with dielectric grease. If you ever need to clean out dielectric grease, BTW, you can do it with any number of solvents. However, I've never had to clean dielectric grease out of a connector. I don't think you need to get too crazy with the cleaning. Your interior connectors probably just need a quick spray with WD-40, working the connection a bit (plugging, unplugging, plugging, unplugging), applying grease, and reassembling. Engine compartment connections might require a light touch of 600 grit sandpaper. Note: Don't use a coarser grit, and don't get aggressive. You don't want to remove plating/tinning. In all honesty, I think craft paper (e.g. paper bag material) wrapped over a small screwdriver tip, wetted with WD-40 or Deoxit, is plenty rough to clean the connections. I would recommend that first. There's no need to remove your dash. Your light connections are around the steering column. The ECU connector is behind the left kick panel. The FSM will show you where all the other connectors are. I've owned two Z's now, and I've never had to remove the dash. In fact I've never had to remove the dash of any car I've ever owned. I do lots of wiring work, so if it were necessary, I'd have done it already. One other thing I didn't comment on before: You mentioned replacing the fuel pressure regulator and fuel pump for good measure. You'll go broke quickly by doing this sort of thing. Not only that, but you'll be depleting a scarce antique parts supply for the rest of us. I've never seen a bad fuel pump or FPR, and there's no reason to believe yours is bad. You should simply test your fuel pressure. If it's good, then both components are good. You can borrow/rent a gauge from many auto parts stores, and you can buy one for around $50. If you're inclined to replace parts just "because," then please make your cast-off parts available to others in the Z community, as most of them will be perfectly good (and we could use them). Good luck with the cleaning! I'm sure you'll iron out at least a few problems just by having clean connections.

See if you can spray some WD-40 inside the switch, and then exercise the switch quite a bit, turning it on, off, on, off. That might work. Zs-Ondabrain also rebuilds these switches. Or it might not be the switch.... Eventually you should upgrade to headlight relays, BTW. Those switches take a beating. No idea about your window.

Ramps: Yes, they're a bit scary if you drive the car up onto them, as there's a slight chance you could over-run them if you're careless. However, if you use them like jack stands, they're quite steady (better than jack stands), and you can roll down off of them when you're done. Jenny, the next garage I build is going to have either a lift or a floor pit! Cleaning connections: Deoxit is excellent, but even WD-40 can do a good job -- rub with craft paper around a screwdriver tip. If the connection is crustier than that, try wetting some paper with vinegar. Even crustier? Try 600 grit sandpaper. However, brand new connectors would be the best of all. If your connectors are anything like mine were, they're practically falling apart.

Good advice from everyone! Yeah, what they said! I still think it's electrical! Fresh oil change, ignition, clean connectors. You should know a lot more after that. About your "dumb question" -- If you have scrap lumber sitting around, try this: Set the emergency brake, and put your car in gear. Put a jack under the control arm of one of your front wheels, and jack several inches. Put a couple of 2x6 blocks under the tire, and release the jack. Jack the opposite control arm, and put 4 2x6 blocks under that tire. Jack the first control arm a few inches more, and add two more 2x6 blocks. Then you'll have 4 2x6 blocks under each tire. Change your oil, and then remove the blocks in the reverse order -- first two on one side, then four on the other, then the remaining two. You can also use jack stands, but they're frankly a bit difficult to get under there -- even the short ones. If you want to get fancier, buy a pair of ramps, but be aware that they like to scoot when you're driving up on them, unless you somehow block them. Another method is to do the above with a couple of 2x6 blocks and two ramps. Substitute the ramps for the 4-block stack. When you're done, just back the car off of the ramps. Easy.