FastWoman

Ben, you need to measure the pressure with a T-fitting inserted between the fuel filter and the fuel rail. (Just add another little length of hose.) Normal pressure should be 36.3 psi with the vacuum hose removed from your fuel pressure regulator. Then with the vacuum hose reconnected, the pressure should drop about 7 psi to 29 psi (at idle). When you rev the engine hard, you should see the pressure surge to 36.3 and then drop into the low 20's as the RPM comes back down. In addition to Zed's suggestions, a stuck cold start injector can also richen your mix. BTW, I just finished installing a "permanent" gauge under my hood, fashioned from fittings from True Value hardware. I used a cheap, generic gauge and a brass T-fitting -- total cost about $12. The gauge and two 5/16" hose barbs both screwed into the T via 1/4" NPT threads. I came up from the fuel filter to the first barb at the base of the "T". Then one side of the T went to the fuel rail, and the other side went to the gauge. No brackets were necessary, as the gauge is small and is held nicely in place just by the hoses.

I go back and forth on the LEDs. This year LED Christmas lights made their big splash in my neighborhood, and the older tungsten lights had mostly died during previous years. It just wasn't the same. The LEDs were cold and unsatisfying. To me there's something magical about a hot, glowing filament that we will miss someday. However as a spotlight on our sailboat.... That's entirely a different issue!

The new kid at my local AutoZone has one of those newer-fangled turbo V6 Z cars, but he knew all about my '78 Z. After discussing common failure modes in my Saturn's O2 sensor (why I was there), we talked archaic analog L-Jetronic stuff for several minutes. I was impressed. Yes, there's hope.

Dude, check the breaker plate in your dizzy to see if it still rotates freely with vacuum applied to the vacuum advance. The vacuum advance mechanisms in Z dizzies aren't very well designed and often/frequently/usually stick. For $100 you can buy a rebuilt dizzy from your local auto parts store (e.g. AutoZone), but supposedly supplies are getting a bit scarce. Backfiring through the carbs strongly suggests a fuel/air mix that's too lean. I bet your engine vacuum is pretty low too.

I'm assuming it's important to you to stick to 100% stock. If not, you might want to install MaxiFuses to replace that fusible link mess. I did it and am still very happy I did. My saga is here: http://www.classiczcars.com/forums/showthread.php?35588-Upgrade-from-fusible-links-to-circuit-breakers&highlight= If you do stick with the stock fusible link assemblies, you need to be careful with the bases, as they can break. (Mine were both broken when I bought my car, and the fusible link blocks were hanging off the end of the wiring harness.) There are no new replacements for those, and in fact they are an integral part of the wiring harness. Your only replacement option would be salvage, and I didn't have much luck finding the things. Obviously I gave up.

Dunno... Tapping with a vice will wear most people out! :cheeky:

I'm not saying household AC is different from automotive DC. I'm only saying the standards are different. You won't find 10 ga wire anywhere on an automobile's 30A circuit, and you won't find a car anywhere that would meet US household wiring codes. .7 ohms/km?! Wow... Impressive!

Rob, I found that the main alternator-to-fusible-link wire in my '78 was pretty small -- perhaps 10ga, if I remember correctly. That's already too small to carry the sort of current that might be sent through that wire. A 10 ga wire is rated to carry 30A in household wiring, and automotive wiring seems to be twice as permissive in general. So Steve's quote of 55A for 10 ga would seem fitting. He says the rating drops a little bit in a bundle, but I think more correctly that it drops quite a lot. When you put the 10 ga wire inside an insulated wall, that's how you get a 30A rating. The alternator wire lives inside a rather large chunk of wiring harness, and it sees quite a lot of engine heat (another adverse factor). As such, I doubt it can really carry the rated 55A before melting its insulation. In my car, I upgraded my alternator wire to 8 ga, if I remember correctly, and then I fused it at 80A. However, if I still had the same 10 ga wire, I'd probably go with a 60A fuse and be rather uncomfortable that the wire might not be adequately protected. Of course I never like risking such things, which is why I upgraded the gauge of my wire. Keep in mind that if your wire gets hot enough, it will melt not only its own insulation, but also the insulation of surrounding wires. Pretty soon your wiring harness becomes toast, and you will have weird electrical problems you couldn't begin to imagine.

I believe the red/white wire is from the fusible link. This establishes that your fusible link is good and that you're getting power to the switch. Try testing for continuity between the switch terminals on the disconnected switch when you turn the key. That's the most direct approach to determining whether your switch is good. Again, red/white is the power supply to the switch, so test for continuity between that terminal and the others.

Yikes, they're now NLA? That makes me wonder how they're going to honor the lifetime warranty. I'm sure more will become available, but I suppose the supply will be trickling away. I guess I got in towards the tail end of a good thing. Anyway, glad you found your problem!

Ezzzzzzz, I don't know the specifics of the Pertronix rig, so I'm just making an educated guess: I would presume different magnetic lobes correspond to different cylinders. If there's anything marginal about the operation of the system (e.g. distance of sensor from lobes being incorrect or marginal sensitivity), and if there's any difference at all in the strength of the trigger for each cylinder (e.g. magnetic field strength generated by each magnetic lobe), then at least one cylinder will be prone to fail while the others are still (barely) operational.

FAIW, Autozone sells a remanufactured dizzy for around $100 with a lifetime warranty. These things don't actually last anywhere near 38 years, due to a bad breaker plate design. It doesn't take long before the breaker plate freezes up and the vacuum advance sticks. The reman parts often aren't very good, but I figure if the R&R is an easy one, why not do it? So far my reman AZ dizzy is doing great. My original reman AZ alternator did start putting out slightly too high a voltage at one point, and AZ was very good about replacing it.

Green tape?! Are you serious?! Hmmm.... Yeah, that's where I'd look.

D'oh! I can't read. Might still be in your distributor. You can try swapping BOTH your #5 and #6 wires AND plugs to see if the problem migrates to #5. If it doesn't, well, that's the entire ignition system after the distributor. I would think that would mean the problem is in the distributor.

In trekkie alien voice: What IS... "carbs?" But seriously... :bulb: Do you also have points? I'm just guessing here, but if the cam (correct term?) in your distributor is worn a bit more on the #6 than the other positions, OR if your distributor shaft is wobbling just right, AND if your points are adjusted so that they barely break as the distributor cam rotates, then you might be (barely) breaking on #'s 1-5 and not on #6.

This is all great news! You might need to lean your mixture out just a bit, so that the TPS can make the appropriate enrichments for idle and WOT without making the mix too rich. I suspect the adjustment would be so minor that you might be able to tighten the AFM's clock spring a bit to do it. Isn't it great to be pulling strong on all 6?! IMO, there is nothing more delightful than a properly running inline 6 motor. It's the only configuration of motor that has inherently perfect primary and secondary balance -- well, that and a V12, which is essentially two inline-6 motors stuck together.

Run your engine in the dark, and look for stray sparks. Your current might be shorting to ground prior to the plug. Check the connection to your #6 injector to make certain it's firing. Obviously check compression. Your problem is probably in there somewhere. FAIW, a weird problem one forum member had (argneist) was that the EGR port on his intake had eroded through to the manifold, bypassing the EGR valve. The leak was dumping lots of exhaust exhaust into his #4-#6 cylinders, causing them not to fire. There was possibly some blockage that prevented the exhaust gas from reaching #'s 1-3. I've not heard of this problem in any other car, but I thought I'd mention it.

I could easily be wrong, but I think having the right fuel/air mix will eventually result in the burning/eroding away of carbon deposits in your cylinders. I suspect there's no compelling reason to clean the valves or intake, beyond clearing varnish from the valve guides and injectors. Flushing the motor oil will clean up the valve guides, albeit a bit slowly, and running a bit of a strong solvent through the gas will slowly clean the injectors. I think that's about the best you can do. That said, the old-school way of cleaning carbon out of a flathead engine was to open up the head and dump rice into the intake. Apparently the rice would bounce around inside the cylinders, and the pulverized carbon would come shooting out the exhaust -- not that I'm recommending that to anyone, but I just find it fascinating!

I think your #2 is the vacuum supply from the throttle body to the thermal vacuum valve, which supplies vacuum to the EGR system. I don't know what year your car is ('78?), but there's a vacuum tubing diagram in the Emissions Control section of the factory service manual, fig. EC-14. You can download the FSM for free, or you can buy a used hardcopy off of Ebay or Amazon. I prefer having the book, myself, because you can spread it out over your work area, unlike your computer.

Oddly, that part on the throttle body (the dashpot) isn't really supposed to have a hose attached to it, appearances to the contrary. All the part does is to ease the throttle down when you come off the pedal.

Jack, the problem is more than a faulty alternator. If it were JUST a bad alternator, your electrical system wouldn't run down that fast. At least a few possibilities come to mind that could be true in any combination: 1. Your alternator is bad. 2. Your voltage regulator is bad. 3. Your battery doesn't hold much charge. 4. You have an enormous short that drains your system very quickly. It's hard to guess which combination of these factors is in play. However, you can pull your battery and alternator and have them tested at an auto parts store. If you know your battery and alternator are good, try measuring your running voltage. It should be around 14 volts. If not, you might have a bad voltage regulator. Also keep an eye on your ammeter. What is it telling you?

Now you want a bad name for a car company? How about Citroën, which almost spells "lemon" in French. It would be somewhat like an American car company called "Lemoen." But then again, a person has only to look at almost any French automobile to understand that nobody in that country would actually care.

Same logic, but I'd recommend mineral spirits. It has a bit of bite but will not attack polyurethane paint (if that's what you've got). Just the same, I think heat may be the way to go.

^^^^^ What JWTaylor said. Lay it out on a 2x4, and whack it. Maybe flatten it in a vice. Or if you have problems with the layout of the holes, use a rat-tail file on it. It's not as though this is a precision bearing.

Jan, do you mean diesel motor oil, or diesel fuel? I use diesel motor oil. (See post 14.) Some people have been known to add a bit of diesel oil or kerosene to the crankcase to flush gunk from the engine just prior to an oil change. Gunk engine flush is a more aggressive flushing agent with higher volatiles. It's a bit like an engine enema. But no, I've never tried flushing with diesel fuel. I've used Gunk flush, though, and it's a great product. I would not recommend it for cleaning anything but varnish and minor sludge, though. Same thing for SeaFoam, which I think is a very similar product.