Zed Head

Texas plates and kind of looks like it's been under water. Apparently it runs though. The hub caps alone are worth thousands, right? "1970 Early series 1 January build date. car number 795 has a little rust but runs and drives white with the blue 4 speed matching numbers has hub caps in trunk if you would lime more pics or ? Call show contact info Nick"

It looks like the electrical part is right, doesn't it? The switch is doing its job, there seems to be a pressure differential. The brakes might need bleeding. Some people say that the 240Z switches need to be reset after the valve moves. I could get my 280Z light to go off, when I had a problem, by pumping the brakes to remove the differential. That was a clue, for me.

Actually this is not quite the same. You need to compare pressure inside the rail to "pressure" inside the manifold. The big confuser for the fuel pressure regulator operation is that they/we use vacuum for the measurement on one side and pressure for the other side. Convert vacuum to pressure and do some math and you can see what's happening. That's what I did in post #103. But I have to go search around for proper values every time this topic comes up. CO's cool tool is a direct reading of what's happening. But a calculator and two gauges will get you there too. Kinser you almost seem more interested in the measurement and diagnosis than actually driving the car. You will do well here...

You can swap carbs on to the EFI engines easily. Bolt on. Pick the car that has the least of what you hate doing.

The problem with the switch is well-documented for all of the Z's. They pit, then get hotter, then the solder joint fails. Wasn't talking about your newer switch. If you want to drive your car in the city and you can't use high beams because of other cars then Big Phil's fix will work. If you decide to use the high beams you run the risk of damage. But low beams will be just like normal, except grounding at a different point. Good luck with whatever you do. The simplest fix, of course, is to find the original problem before deciding on a "fix". Even Big Phil knew that his real problem was somewhere in his wiring harness.

Big Phil shorted the low beam so that it always has ground whenever there is power. You have to watch the video. The low beam will always be on by Big Phil's video "fix". It's shown in the wiring diagram.

Looks like a decent quick-fix. I think you end up with both filaments on, high and low, when the high beams are on though. So more current than normal passing through the HL fusible link. Might be more for the switch on top of the column also, if I recall right. That switch already gets hot with just one beam circuit running through it. Might melt if you run high beams for long. Unless you put a relay at the fuse box. Good old Big Phil...

In real life usage the backs of the valves tend to get coated with crud. From the PCV system and back-flow of exhaust gases and fuel vapor. The fuel additive industry makes a fortune claiming to be able to clean them. Not to be a downer, it's cool for that first dyno run or individual races or drag strip runs but long-term might not stay effective. There's a neat thread over on Hybridz about weight reduction and balancing of rocker arms. Lots of grinding of non-critical areas.

Did you bypass the switch to see if it's causing excess resistance?

My burned EFI-Pump relay has a diode and a resistor in the circuitry. A few more pictures of Dreamzz's burned relay might show something. Maybe I'll pull mine out and take a look, to be sure it's not slow-cooking.

Actually it "unlights" the brake warning lamp. So the relay isn't as simple as I said previously. It's a normally closed relay. One of those 5 pin Bosch units, I think, would work. Hundreds in the wrecking yards and eBay for cheap. I remember some basic AC to DC conversion stuff, with rectifiers and wave forms getting their bottoms flipped over and all that, but learned it long ago and only 101 level and it's all corroded now, so I can't even make a guess on what N is doing here. The relay in question sees 12 volts through the switch contacts, where the power comes through the lamp on its way to the relay, where it is grounded, and it sees N voltage through the relay coil which opens the circuit causing the lamp to go off. The relay coils are what has crisped here. Maybe my relay is living on borrowed time. Is there any way to tell what voltage a relay coil is rated to? Marks, codes, etc. The coils look just like the EFI and fuel pump relay coils. Which get crispy also, over time. The brake warning relay also tends to get wet since water pools in that area when there's a leak. There are no drain holes.

N has a branch off to the relay. It must get wired to battery voltage in the swap diagram. Can't speak to what it's rated for, voltage-wise, or even what comes out on N. Not my forte, and mine works. Being lucky, I guess. Anyway, many possibilities.

Could be. N enters the VR and probably serves multiple functions. See attached, below. CO knows more. @Captain Obvious Dang, looks like he's here... posting anyway!!! Output is in amps. At 12 volts or higher. Amps do the damage. My relay has been fine on the 14+ volts my alternator puts out on the fuel pump circuit. Good luck. The key is to have power to the control function of the relay only when the engine is running.

12 volts should not have fried it. That's what it's designed for. Are you sure it's dead? I had the same problem with the battery draining. The atlanticz wiring diagram doesn't take the relay in to account. The relay is supposed to get power when the engine runs, but the ZX swap scheme gives it power all the time. I ran a wire over to the fuel pump power plug by the passenger seat to use the same power circuit as the pump, which only gets power during starting and engine running. It's about as basic as relays get, if you did fry yours. Any old relay should work. The line from the alternator is the power wire that gets misdirected after the swap. It actually comes through the VR. Weird that the diagrams don't show it though. This is the 1976 drawing.

Suddenly all of those old worthless automatic transmissions have value. I'll bet most have been scrapped. Could be a problem.

Looks nice and not a bad price. Location might help interest. Lot of Main Streets around. I can almost read your plate but not quite.

Actually, his basic problem is an idling problem. Lots of traffic, and sitting while idling causes the plugs to load up and the engine to run rough. A good drive and quick engine cut might offer a clue, but the problem is the idling. I know that my old engine would start to run rough at idle, I'd take it out in the country and give it an Italian tuneup and it would idle smoothly for a while. Then load up again. IT was fun for a while but got old eventually. I put my spare engine in to fix it. 246's issue is similar. Not clear how the cracks cause the fouling though.

Sounds pretty good. Nice that the the fuel Injection guys owned up and fixed the injector problem. Although, you'd think they would know better. I see 32 psi on the fuel gauge, and 20 inches of mercury on the vacuum gauge. That calculates to about 42 psi fuel pressure with no vacuum. I think that you can borrow a gauge from the local auto parts store, for a cross-check. They require a deposit but give it back afterward. Looks like you're still working with a gauge of unknown quality. Good luck. Carry on.

That's a good one. 1-5-3-6-2-4 is correct. Maybe he some wires switched. That fits bad spark.

I'm not trying to crush ideas, just reviewing past discussions with Jalex and others. The simplest solution would be to find a mechanic who knows engine basics but they seem hard to find down there. Any good mechanic would look at those six plugs, if they are actually new and came out like that, and have some ideas. The picture of all six plugs fresh from the engine is new info. Seems much clearer than any of the past discussions about Far311 cams, and percolation, and poor idle.

I thought it might be bad valve seals myself. But folks are fairly convinced that the fouling is fuel fouling. My old 76 engines with worn valve seals had all six plugs pretty dirty, but not wet though. He says that all six cylinders give a solid 180 psi pressure reading.

He has carbs though. What would the "compensation" be? The air-fuel mix happens at the carb and should be essentially the same for each of the three runners being supplied. The other side of the view would be "how can an engine run on two (or three) cylinders. Assuming the clean ones are "dead" and the dirty ones live. He said that those plugs were actually in the engine but there's no way to confirm. Hopefully he wasn't just putting new plugs in the picture for comparison. One reason we've focused on ignition is, like you said, internet diagnosis is difficult. If we could confirm that spark is good for all six then we could ignore spark and focus on fuel-air, or oil, or compression, or valve timing, etc. The power balance check is a good idea except for the fact that he has electronic ignition. And ignition modules tend to be sensitive to having nowhere for their spark to go. He might fry his Pertronix module, as CO implied in his comment.

I have another wild arse guess, based on an old memory about the Pertronix trigger ring and the tape holding it on. I believe that the magnetic ring is actually six magnets isn't it? Or it's six bits of iron that pass a magnetic sensor. Not sure which. In the past, Jalex noted that the tape was peeling off of his, if I recall right. If the trigger ring slipped, could this give two bad triggers out of six? Do the bits inside the ring move separately? I've never had a Pertronix igntion system so don't know all of the fine details about how they work. But it might explain why the plug wires and plugs and cap all look good but there still seems to be some misfires. Each magnet or iron piece triggers a certain cylinder. Another reason to use an analyzer, I think, then work backwards to find the cause. In the meantime maybe take a good close at how the Pertronix parts are fitting under the cap. Edit - it's magnets. Hall effect is the term I couldn't remember.

I've never used one of those flashing spark checkers, the kind that fit between the plug and the wire. Has anyone used one of those? Would a misfire show up in the flashing even though it's fast? Don't know if the human eye could catch it. Here'a thought that just came to mind. One of those old engine analyzers. That would show misfires, if I recall right. They might still be around down in Panama. That would be a quick easy way to show if spark is good or bad on all six at the same time. If I was down in Panama I'd try to find a shop with one of these I think. Might make things clear pretty quickly. http://www.enginebuildermag.com/2015/10/old-gold-vintage-engine-analyzers-and-distributor-testers/

I started a new thread on just the unusual pattern of fouling. Somebody might have seen it before. It's weird.