FastWoman

Your fuel pressure is just where it should be. Your FPR seems to work fine. The $20 question is whether your fuel pump can maintain a healthy pressure and flow when it heats up. That's how mine failed. Fuel pressure was fine when I started it, but after I took off down the road, the pressure and flow began to fade until the engine died. Then when the fuel pump cooled down, I could fire the engine up again, and after 10-15 min, the engine would die again.

Correction: I have the Standard FJ3 injectors. I had forgotten that sscanf had a different part # than I do. The FJ3 injectors are listed for the 280Z. I can't say whether they differ appreciably from the FJ7. I got mine for $150/set off of ebay. You can find the same deal there now: 75 76 77 78 79 80 81 82 83 Datsun 280z Fuel Injectors | eBay The only incompatibility I found was that the hoses were about 3/4" too short. So I cut them off and clamped on longer hoses (pretty easy).

LenNY! LenNY! LenNY! Go, Lenny, GO!

I replaced my old (working, but quite elderly) OEM injectors with the Standard Ignition FJ707T, and it ran about the same. (It still had other issues that I corrected.) I've been running those injectors for the past few years with no problem. The hazard with the old, cleaned up injectors is that they can leak, which of course makes them dangerous.

I, too, appreciate your hard work. This is a great place -- a quiet corner of the internet where a bunch of friends can come together and share a passion for some fine old cars -- a refreshingly civil place. Thanks!

If free exhaust flow (hang the noise) is what your customer wants, then you don't need the midpipe muffler. That doesn't come with the exhaust kit. That said, the Magnaflow midpipe is a straight turbo muffler and does not restrict exhaust flow. But it certainly makes the exhaust more civilized. We regularly drive my Z between the coast and Richmond. It's a noisy, but otherwise comfortable car. If I had the exhaust drone added to all the road noise, I think that would tip me over the edge. Just saying! As I recall, this is the one installed on my car: http://www.summitracing.com/parts/mpe-14416/overview/

Well, in all fairness I should tell you that the exhaust is a bit noisy on initial warmup -- at idle, when it's blowing sort of hard. But then again, my idle is too low on warmup because of a stuck AAR. Hearing this, my uncle commented, "Needs a muffler!" Of course he's used to cars you can't quite hear running. Otherwise, the exhaust doesn't have any of that obnoxious raspiness under load. It just has a low, chesty rumble at idle that smooths out around 1200'ish RPM and above. My intent with this exhaust system was to try the turbo muffler and to replace it if I couldn't live with it. I can live with it, but I'll probably replace it with a conventional muffler next time around. The midpipe muffler is apparently an essential element for taming this system and getting rid of an annoying drone sound at cruising, and it works great. However, if it were available, my preference would be for the OEM-style exhaust -- maybe a tad bigger, but not much. I should also mention that the system sometimes needs a bit of tweaking for a proper fit, especially around the transmission. Of course that's where you'll add the midpipe muffler, so you'll be modding the system anyway.

Now there's another silver '78 that's proud of her bumpers! Nice!

Motor Sport Auto premium exhaust with a Magnaflow 4" midpipe muffler nestled neatly in the tunnel. Motorsport! 70-78 Premium Exhaust - The Z Store, Nissan-Datsun 240Z-260Z-280Z-280ZX-300ZX(Z31/Z32)-350Z-370Z Parts A bit of a rumble at idle, but not uncivilized. It doesn't sound at all like some tooner kid's Honda. It does sound like the Z is endearing itself to you. They do that. My '75 280 was my first EFI car, and I thought all the Rube Goldbergery on the side of the engine (instead of the carbs) was simply awesome. And the chain drive, flat tappet, OHC valve train? Just plain sexy, in a gearhead sort of way. For me, the joy of the Z isn't the performance. My Miata is more nimble, and so many modern cars will leave a stock Z in the dust. (With mods, though, the Z can still fight very respectably.) But there are very few cars that are as sexy as the S30 Z models. And I've always found my Zs (both of them, owned at different periods in my life) a true pleasure to work on. The Z is an easy car to fall in love with.

Congratulations! Now tell us honestly, don't you think that EFI L28 is a sweet engine?

My experience is the same as Zed's. I think priming helps a little, but it doesn't cure the problem -- not by a long shot. I think that's because the injectors and their hoses are still full of gasoline vapor even after priming. I've not tried the ZX cooling fan, but I bet that's the ticket.

Wow... texting while driving through an INTERSECTION?! (What could go wrong?) :stupid: Did he stop? If so, I hope you threw his smart phone on the ground and smashed it.

It sounds like a garden variety "hot restart" issue to me. This is common with the 280Z -- probably an incompatibility between modern ethanol-gas formulations and our operating fuel pressure, in combination with leaky fuel system components (e.g. fuel pump check valve). Most recently it came up here: http://www.classiczcars.com/forums/fuel-injection-s30/51224-1976-280z-fuel-injection-issues.html Search the forum for "hot restart," and you'll be able to read lots of theories and discussions about how/why this happens and how to remedy the problem (somewhat/mostly).

Christopher, on rereading your original post, I'm pretty sure the stutter is "normal" (or at least common) for this car. This is a known issue. When you warm up your engine and shut down, and especially after you wait for 10 min or so, then the engine will run very roughly when you restart it. It will only even out after you run the engine a bit, especially if you put it under load (e.g. pull out). There are many theories about why this happens. You can search the forum for "hot restart issue" and find lots written about it. My own take is that ethanol gasoline is too prone to vaporization at the low operating fuel pressure used by our cars, particularly if it is a winter formulation. There are a few things to check/correct that will lessen the hot restart problem. First and foremost, your fuel rail needs to hold pressure. There is a check valve on the fuel pump that prevents backflow. If that check valve is worn, the fuel pressure will bleed down fairly rapidly. Also worn injectors will leak down pressure (which might have been part of your original problem). Once fuel pressure has bled down, the engine heat will vaporize it, and thus your injectors become locally vapor locked. It takes a bit of run-time to squirt the fuel vapor out of your injectors and spray liquid fuel again. You should test your fuel rail for leak-down time. It should probably lose no more than 5 psi in a half hour. There are also two types of insulators at the base of each injector. The old style is aluminum, and the newer style is plastic. The plastic insulates better. You have the '76, which doesn't have the vented hood. A vented hood from a '77 or '78 helps. Insulating the fuel rail helps a tiny bit, but I think most of the vaporization problem occurs at the injector tip. The oil gauge's slow response is normal. It's just the design. It uses a bimetal element to flex the needle. If your gassy smell is gone, it might have been a leaking injector. That's a common enough issue. Crack in the FPR -- no good. That could also be a source of the gassy smell. The split in the vacuum hose could cause the engine to run too rich (fuel pressure too high), and that could be a source of "gassy" exhaust.

Wow... spooky! I had just mentioned a possible harmonic balancer issue to someone in another thread! I'm glad everything came out OK. Hope your wallet isn't too much lighter.

No danger. All you risk is a bit of wear on the belts, but a trip across town is no biggie. FAIW, it's a very easy job to tighten the belt(s) yourself. You can also try spraying the belts with a bit of belt dressing.

Subwoofer

Ha! Zed beat me to it! (I had walked away from my computer. I don't type quite that slowly!)

I don't know whether it's a potential issue with Z's, but I've heard of some old cars (e.g. Miatas) having issues with the harmonic balancers deteriorating, such that the timing mark randomly shifts. Have you verified that the timing mark really is TDC? Also have you pulled the valve cover and verified the valve train is aligned correctly to TDC? Just a tooth off can cause pretty crappy running. Also the distributor might be a tooth off, so that the rotor only aligns to the correct plug when the timing is retarded. Advance the timing enough, and the spark skips to the next plug, hence cylinders starting to drop out.

Nice! I look forward to seeing the video! Happy New Year!

We forgive you. Great progress! You should video your test vehicle running for the first time on your Hellfire system. Just curious: Would coil-on-plug be possible with your ignition management version? I think you said lost spark with flywheel timing would be possible. Well, you've put in a great effort. You may now take the evening off, but be right back to work on it tomorrow!

Thinking about my solution, I can only imagine two disadvantages: -- Without passage through the tank, the fuel in the recirculation loop could get warm (hot day, heat soaking). This could aggravate hot-restart issues. -- The system could be difficult to prime if run dry.

Pretty much. The return would circulate directly into the intake of the fuel pump. This configuration wouldn't do much to churn/mix the fuel in the tank, but that's not really necessary. At least it would provide a route for return flow.

Maybe you could put a "T" fitting on the low pressure line between the tank and fuel pump and connect the return line there.

Hey, welcome! The reman injectors should give you a better spray pattern and more even fuel distribution between cylinders, which is always good. However, I'm very skeptical that was your main issue. If the excessive fuel smell was in the exhaust (perhaps along with a bit of black smoke and fouling plugs), I'd say your Z was running to rich. It's rare for that to be an injector issue. Moreover, injector issues usually surface gradually over a very long time, not suddenly. It's more likely you had a bad connection to your coolant temp sensor, and when you did all your work, you jiggled the connector enough that it made good contact again. All the sensors and connectors in the thermostat housing get a lot of abuse, and rotted/corroded connectors are a common problem. Either that, or the gassy smell was coming from your fuel tank system. If your filler neck and/or ventilation hoses are split/rotted, you can get gas fumes in the cabin. You can also have a cracked joint in your fuel/air separator or a crack in a ventilation check valve. If this is the case, don't be surprised if you get another wave of gasoline fumes with your next fill-up! Anyway, you certainly improved your situation with the injectors, but I doubt that's the end of the story.