FastWoman

That one looks fine. However, the approach I took was to have my T vertical, with respect to the ground (so that it would be oriented like the letter "T"). The bottom leg of the "T" connects to the fuel filter via a very short length of hose. The gauge points away from the engine on one of the two top legs of the "T", and a hose goes from the other top leg to the fuel rail. The gauge is then supported via the hoses and faces upwards. The path of the hoses forms a 90 deg angle, rather than the 90 deg bend that it would take if just a single hose were used. EDIT: Be careful fitting high pressure 8 mm fuel lines on 3/8 barbs! They can eventually split! I wouldn't go any larger than a 5/16" barb/nipple.

Varnish is brown. I'm guessing the black gunk is like soot? If so, it's deteriorated rubber from your fuel lines. It gets recirculated through your fuel system and back through the return line to the tank, where it deposits as a fine film all over everything. The only thing that will remove it is mechanical action. I found a pressure washer very effective in blasting the stuff loose, although you won't be able to get every nook and cranny. I suspect whatever is deposited on the walls of your fuel lines is there to stay. I'd replace each and every fuel line, including the vent hoses. The largest hose is about 5/8" and is hard to find, but you can get it at a tractor supply. Note: These are all FUEL lines. Don't use the heater hoses, or they will fall apart.

You can find the ECU beneath the DRIVER-side kick panel. I don't know what you mean by an "injection relay." If you mean the main ignition relay, that's inside that black metal box mounted to the passenger-side inner fender. Unscrew the screws around the backside of it, and remove the plastic cover plate that inserts into the back end. The best advice I can give you is to get hold of a factory service manual for the '78 Z (the Nissan publication). You can download it online for free here: http://www.xenons30.com/reference.html Better still, look for a paper copy on Amazon or Ebay. They come up occasionally. Without knowing more about your situation, I'd suggest attention to the following items: (1) Is there a working connection between the ignition coil (-) and the #1 terminal of the ECU? That's the clock signal that induces the ECU to fire the injectors (once every three sparks). (2) Do you have +12 feeding your ECU? (3) Are your drop resistors well connected and in working order? They are in series with the injectors and are located in an assembly just beneath the master cylinders on your firewall. (4) Are your injector connectors in good condition? They often get rather crusty and crumbly.

Rob, sometimes the steering column switches get pretty dirty, so that could be the problem too. If you can squirt some contact cleaner inside the switch and "exercise" it, that might do the trick. Also Zs-ondabrain refurbs these switches. He hangs out a lot in electrical.

Cheap fuel pressure gauge (under $10): Go to your local hardware store, and find a cheapo Chinese generic pressure gauge. I found one at True Value for under $5 with 1/8" NPT threads. I then found a 1/8" NPT "T" fitting and some 5/16" nipples to go in the remaining two ends of the "T." I think my total cost was $6 or $7. It's surprisingly accurate. I got the thing to install (permanently) inline between my fuel filter and fuel rail. If it doesn't hold up, no biggie (as long as it doesn't spray fuel!).

If you have a short, at the very LEAST you should wrap the bare wire with electrical tape. The only thing that should be keeping shorts from happening is intact insulation. FAIW the bullet connectors are the least likely to give you problems. The various Bosch-type connectors (on the injectors, coolant temp sensor, thermotime switch, cold start valve, air regulator, throttle position switch, air flow meter) are more likely to be corroded and deteriorated. If they make or lose contact by your wiggling wires, they're in terrible shape and need cleaning or replacement.

... or you might be able to apply the engine vacuum from another car to your Z's vacuum advance, via a long tube. Mighty vac = hand vacuum pump

Well, after you eliminate all the simple stuff -- and also the not-so-simple stuff -- then you're left with the ECU. What a few of us have found is that the ECU can drift over time in the pulse widths it delivers to the injectors. This drift always seems to be in the direction of a lean mixture. So after you've ruled out everything else, you can modify your coolant temp sensor circuit with an inline resistor to up-regulate fuel delivery, richening your mixture. If you use a variable resistor, you actually have a means to tune your fuel/air ratio. ... but we're getting ahead of ourselves.

Eric, I could suck on my vacuum advance hard enough to move it. It's not easy, though. IMO the easiest and best way to check it is really just to give the whole assembly a twist with your fingers. It should move smoothly and not feel gritty, as Zed suggests. I think if you were just to actuate the thing under vacuum, you'd lose that tactile feedback and couldn't really determine whether it's starting to stick/jump. $50 for a rebuilt dizzy is a good price, BTW!

NO, NO, NO, NO, NO! Slight movement is good. It keeps your contacts good. IMO that's why cars usually develop problems just from sitting too long. Your problem is that your connectors are crusty, crumbly, and corroded, not that you need to jiggle this wire this way and that wire that way. Your only path to salvation is to clean those connectors up -- or replace them if they are beyond redemption. Your Z shall rise again!

Yay! Glad it helped you!

KD, vacuum to the FPR will drop the fuel pressure. That's what it's supposed to do. However, if you can't get a static pressure higher than 37, your pump is marginal at best. FAIW, the OEM FPR is VERY GOOD at regulating fuel pressure quickly and precisely. I did try out a cheapo chinese Aeromotive FPR knockoff, and it regulated pressure very sloppily. I returned it for a refund. I have no idea how tightly a real Aeromotive FPR regulates, but I doubt it could do much better than the OEM.

Also make sure your distributor's vacuum advance works. Take off the cap and rotor, and try to rotate the innards with your fingers. They will be under spring tension and should move smoothly. They should obviously also move if you apply vacuum to the vacuum advance fitting. You should get this to happen if you suck on the fitting really hard. The vacuum advance is poorly designed in these cars and prone to failure. You can get a rebuilt unit for around $100 at your local auto parts store, but supply is limited. When your mileage is absolutely terrible, the most likely culprits are misfiring (usually ignition problems) and air/fuel ratio problems (most likely rich, but possibly also extremely lean). Dirty/old injectors don't usually cause bad mileage. The best place to check your CTS resistance is at the ECU. Remove the passenger kick panel trim to expose the ECU. WITH YOUR IGNITION OFF, remove the ECU connector by flexing the little clip and pulling the connector straight off. (It's hinged on one end.) Then measure between contact #13 and ground. By doing it this way, you're also checking the integrity of the wiring and the connectors from the sensor to the ECU. Often the connector on the CTS is corroded and/or crumbled and does not make proper contact. This is true also of the thermotime switch connector next to it.

Congrats, Cesar, and welcome!

KDMatt, your pressure should rise higher than 37 psi static pressure -- more like 45 to 65 psi, as I recall. It sounds like your pump might be failing the same way mine did. It would pump just enough pressure to pressurize the fuel rail and provide some return, but the pressure would start to sag as the pump warmed up, leaving my engine in a lean-running state and with no return fuel flow to the tank. You're going to find out a lot more by hooking up your fuel pump, pulling off the return hose from the fuel rail, and hooking up your long hose there. Put your fuel pressure gauge on a "T" fitting between your fuel filter and fuel rail. Then leave your engine off, but hot-wire your fuel pump. If you do this for a long time, then also put a battery charger on your battery. Now fire up your fuel pump, and watch the gauge. You should get 36.3 psi with the engine not running, as I recall, and you should get a healthy return fuel flow. (Mine reached this pressure, but the return flow was meager.) Then just let it run for a while. Take a break, and come back to it a half hour later. It might look a lot different. (After 15 or 20 min, min was down to 25 psi, with no return fuel flow.)

Yeah, road trip! Grantf, the yogurt cup is tapered, so it fits like a sink stopper. I don't really know/remember where on the yogurt cup taper the thing fits, so I don't know if a beer can would also fit. I guess I'd have to try it. Unfortunately we buy our beer (and softdrinks) in bottles, so I'd actually have to go out and buy a canned beer for that!

A set of Sorensen or Standard Ignition injectors should work fine. They're much cheaper. I'm running Standards on my Z.

When you first start the car, it's running very rich. Then it gradually leans out as it warms up. You're almost definitely running too lean, rather than too rich. That can give you incomplete combustion and the black, sooty plugs and exhaust that go with it. That can also give you backfire through the intake, as the burn takes a very long time and can extend through the next intake cycle. To verify that you REALLY DON'T have any intake leaks, try my yogurt cup test. For some reason nobody wants to do it, but one guy on this list would have saved an ENORMOUS amount of diagnostic time if he had simply followed this advice. If it helps you to do it, consider it a "beer can test," although I don't know whether a beer can is really the right size to plug the intake. You'll need one cup of Yotastic yogurt -- any flavor you like.

That's what I'm thinking too, which was why I suggested replacing ignition components. Sometimes the center contact between the cap and the rotor can be bad. For instance there might not be physical contact between the two.

If your maintenance ignition components are old, just replace them. It's not expensive. You need: NGK B6ES-11 plugs (pretty sure that's the right one) NGK blue spiral-wound plug wires cap rotor Also inspect your distributor. Does the shaft wobble? Does the breaker plate (what you're looking at when you remove the cap and rotor) turn freely and without binding. If your distributor is bad, you can (sometimes/usually) buy a rebuilt one from your local auto parts store for around $100.

To be clear, did you still experience a 3000 RPM rev-limit with the TPS unplugged? If you didn't, that *IS* the source of your rev limiting problem. You then would need to verify the TPS is working properly and adjust it correctly.

If you want to look at your return fuel flow, just get a long, clear vinyl tube, and connect it to the return line on your fuel rail. You can watch what comes out, and you can either pour it into a gas can or return it directly to the tank through the filler neck. When my pump was just starting to fail, I found there was no return.

Yeah, but what happens ABOVE idle requires gauges in the cabin, dynos, or somesuch. I guess I'm sometimes cheap/lazy. I'll probably end up running some vacuum line into the cabin for some on-the-road tuning someday.

I suppose it all comes down to shifting style. I think a dashpot helps to establish a certain rhythm in shifting. I see others agree and experience clunkyness and stalling without one, so I'll probably search for a solution somewhere. I know there's a dashpot on a Miata (which I own), so logically I should pop the hood of my Miata and see if a Miata dashpot would fit a Z. Duh! (Too many projects, too little time.) Thanks, guys!

I think that would be true, Olzed. However, I've heard of some people trying to mount a righthand drive rack up-side-down -- other forums, other types of cars, as I recall. So over there in the UK, Bippu, you might want to find a lefthand drive ZX rack from the US and flip it over for your righthand drive car. Check out the HybridZ forum. They discuss this sort of stuff a lot. Some of the members seem to have a good retrofit worked out using a Subaru Impreza (?) donor rack. As I near a half-century of life myself, I often ponder whether I should try to retrofit with P/S. Then whenever I top off my tires (which are not the big, fat tires some of you guys run), I wonder what the big deal was. Running a skinnier tire helps a LOT with steering effort. I'm currently running 195/60R15 Bridgestone Potenza Grids on Panosport rims.