Zed Head

Changing the thermostat is super easy. Get your thermostat at this place and get a new gasket too. https://zcardepot.com/engine/cooling-heating/thermostat-160-degree.html https://zcardepot.com/engine/cooling-heating/thermostat-gasket.html MSA has them also. Kind of hard to find on their site but they're there.

How long will it idle with the pump turned off? Could just be residual pressure from flexible fuel lines. I'd let it idle until it dies to be sure. The fact that it runs rich when the pump is on indicates that you have one or more of the common Z EFI problems. Do not adjust the AFM, unless it's already been messed with. If you find that, adjust it back to where it started. Your best path to getting it running well is to go through the tests in the EFI Guide. Clean and check all of your electrical connections. Read through the Engine Fuel chapter of the FSM and you'll see how the fuel pump circuit works and why the PO added that switch. If the engine runs right you shouldn't need it. It's a band-aid.

How far off was the lash on the valve that lost its pad? Curious if the PO adjusted it to run without the pad, or if the pad just fell off and he/she kept running it with no adjustment.

That's a lot of K&N bashing above, but those nice-looking foam pieces that people use on their ITB's or carburetors are probably worse. Just know the tradeoffs is the message. K&N's are dirty filters.

And, just ignore test results if you mean well. It's a top priority, whether it's achieved or not. K&N is a marketing company. Of course, efficiency is undefined so it could mean flow. Plausible deniability.

Check out the filter for the filter. FLOW is important. Until they have something else to sell you. Then, not so much. http://www.knfilters.com/news/news.aspx?id=5690

K&N made their name in the dirty filter area. They can get soaked in water, like when you dump your dirtbike in the creek, and will clear up after you clear the cylinders of water. The competition was oil-soaked foam though, not paper. There used to be ads out there showing how the dirt would build up on the oil soaked outer surface creating more and better filtration. Supposedly the dirt would drop off as it the buildup got too heavy, like some sort of self-sustaining media. I remember being fascinated by the concept of more dirt resulting in a cleaner air supply. Looking back, it was all marketing BS. I copied a segment from K&N's web site that should immediately trigger anybody's BS sensor. Setting the stage, mentally, for flow is more important than clean if you want to "win the race". http://www.nicoclub.com/archives/kn-vs-oem-filter.html http://www.knfilters.com/filter_facts.htm

Run the pump without the engine running and see if you can hear the hiss. Squirt some carb cleaner at the leak area and see if the sound changes. Grab the injector by hand and press it down and see if the sound changes. Pull the injector up and see if the sound changes. Lots of ways to learn more. Not uncommon for the seals to harden over time, then some bumping and moving can create a leak. Would have been super easy to replace the seals while the manifold was off. Still not that difficult. And they're cheap. I have a vague memory of writing this before.

The vacuum cawk, if you have one, also closes the coolant supply off completely at certain settings. Weird how complicated Nissan made their system.

The FPR can make a hissing noise. Did you use new seals and insulators on the injectors, small and large (the round rubber pieces)? Are you using the two-screw clamps? They actually put some pressure on the lower seal by tightening on the top, big, insulator. Does it run like there's a vacuum leak?

No offense intended on the "simpify" misspelling. I left it because it seemed funny. Oversimpify should be an actual word, I think.

The title of your thread is Wideband O2 Sensor. I missed the changeover point. I think that you're oversimpifying. It's a complex device.

Problems like these are why we have hobbies like Z cars in the first place. Worlds colliding here...

The ignition module for the 260Z is by the fuse box n the cabin. It's a cool-looking finned aluminum case. The gear-like thing is called a reluctor (wheel) and the trigger signal is generated when the metal tooth passes by the magnetic pickup coil. The FSM describes it well, at least the 1976 version does. If you start messing with different distributors, check the breaker plate action before you get too involved. Thee are many distributors out there that will trigger the ignition module just fine but won't have a usable vacuum advance mechanism.

You raise a good point. I realized that I don't really understand how the sensors/gauges work either (can't say that I do now either). Innovate has a paper that does a good job of explaining it. Excess fuel left over after all of the oxygen has burned apparently also cause a voltage in the sensor. The voltage is then used in a calculation to give the ratio. Pretty interesting and more complex than I had thought. It's the "pump" that makes the difference I think. http://www.innovatemotorsports.com/resources/news3.php Here's another. http://tayloredge.com/reference/Science/oxygensensor3.pdf One more. http://www.megamanual.com/PWC/LSU4.htm

Easy to get confused, especially since most "high-energy" coils (assuming means coils for high-energy ignitions, commonly assumed to mean constant current systems, like the GM HEI system) are below 1.0 ohm. The GM HEI coil is about 0.7 +/- 0.1., for example. Plus the FAQ's give conflicting information, and say 1.5 ohms is the limit. http://www.123ignition.nl/faq.php

What is the rate of this fluctuation? In other words, how long does it take to go from 800 to 900 and back to 800. How much time from 800 to 800? One second, two seconds, less than a second?

Here's a couple of Articles on electronic ignition. The various extra sensors outside of the distributor are for emissions purposes, to run that extra pickup coil and change the timing based on engine temperature. If you're only using one pickup you don't need them, you can simplify. The electronic ignitions use ~ one ohm coils and no ballast. The common early Pertronix swap isn't a "high-energy" system like the later electronic systems (GM HEI, for example), or the 1978 and on 280Z systems. It's "poinless" so lower maintenance but there are better options out there. http://www.classiczcars.com/articles/technical-articles/electrical/replacing-the-280z-tiu-with-an-hei-module-r67/ http://www.classiczcars.com/articles/technical-articles/electrical/gm-hei-module-install-r69/

@Mike Maybe Mike knows what's up...

I was kidding. 13 years is a long time. It's a good explanation though, of a topic that can be confusing.

It took you 13 years to get your thoughts down on the screen? I can empathize.

This guy, TimZ, found a rebuild kit for the original capillary control valve. Interesting reading. http://forums.hybridz.org/topic/126131-280z-heater-water-valve/ I've found that the heat supply available from the stock core and coolant flow rates is waaaaayyy more than needed. I have a similar valve to the one CO used and I had to extend the arm on it so that it only opens a small amount. Even so, I only use about 1/4 of the range of the heat control lever in the dash. Still waiting for somebody to find a complete assembly that we can transplant over that will do normal things like blow hot air from the dash vents, and fresh air through all of them at the same time. Those Z designers must have worn heavy coats and sandals all the time, based on their choices.

A cylinder pressure check (aka compression check) will give a good idea of if the valve is bent. After you get the lash pad reinstalled. I wonder if a PO didn't notice that the pad was missing and just readjusted lash to make it work. Better check lash even if you don't adjust it. Cold measurements are still informative.

Hence "boner"?

Sorry about that. Didn't mean to create an ordeal for you. The car looks good, my scrolling finger gets tired though.