NewZed

Your thread is interesting, but probably not for your original reason. To those who question how an R&P can be cheaper than a set of tires - ivemade is in the region of the world that makes most of the world's stuff.. He just happens to be in the R&P region instead of the tire region. To ivemade - the desirable R&P ratio is determined by the transmission ratios and the tire size. Most cars come in about 12:1 on first gear x rear ratio (for example 3.062 x 3.9 for a 280ZX), and use about a 24 - 25" tire. Many early transmissions had very low first gear ratios, like 3.592 (with the 3.36 rear gear - 12.07) for the early 240Z, but that changed over time to higher first gears, and lower rear gears. So you need to do the math from first gear to tire size to decide what R&P ratio you want. It's interesting outside of your goal, because you know somebody that can make custom ring and pinion gear sets. The ring gear size is not changed when the ratios are modified, it's the number of teeth, with the ring gear size kept the same, to fit the housing and differential carrier. So if your guy really knows what he'd doing, all you need to do is give him a ratio and a ring gear size and he should be able to tell you what he can do, within a certain range, like 27:1, or similar. As I understand things... p.s. my use of terminology could be off.

Thanks. Still not clear what caused the temperature instability to go away (or what caused it in the first place). So you did everything at once, or did 1 first, then 2 and 3 at the same time? And the line from the water pump inlet that comes from the thermostat housing would just allow flow through the pump when the thermostat is closed. Not seeing that correlation. Probably insignificant in stock form but it actually is another short circuit for the pump, but a little different. A loop of coolant that doesn't pass through the radiator. So it cools the engine and head but doesn't get cooled itself. Anyway, it was an interesting problem. If you get a chance and want to add to the body of knowledge you might open up that ball valve and report what happens.

For the record - you did these three things in order, and confirmed the problem still existed for #1 and #2. But it went away when you did #3? I'm kind of nerdy and like the scientific approach. Just wondering.

Sounds like it's flooded, and the plugs are fouled. Remove all of the plugs, clean them up (or replace with new) and let the cylinders dry out. Don't make it complicated. It ran before, you have spark, wet plugs show that there's fuel. Assuming the "wet" is fuel and not coolant. Shops have been known to hoon a customer's car. Is the wetness fuel, for sure?

The comment about the AAR was just a point about things not working right. But it would be worthwhile to make sure it's not stuck open. Anything that lets air get by the throttle blade. Don't forget the EGR system. They've been known to leak. Intake manifold gaskets too. If the engine is running rich, any vacuum leak at all will raise idle speed. You should be able to drop the idle low enough with the idle adjustment screw that the engine dies. The fact that it stays down after stalling the engine seems to point at the BCDD. It's designed to use intake vacuum to determine when to open the bypass port, I think, along with engine speed and a solenoid. Could be that your high idle is self-reinforcing by creating high vacuum. Maybe. The system is described in the Emissions chapter.

It's not the CSV. That valve just adds fuel when starting. The BCDD can do odd things like that. It has a diaphragm that can leak and bypass passages that could get stuck open. Could also be a sticking throttle blade. Either linkage or gummed up in the throttle bore. All of these things have caused a high idle for many people in the past. Try pulling up on the throttle pedal with your toe to see if it's the linkage or blade. The BCDD is harder to diagnose. If the vacuum advance hose was on the wrong port then other things may have been messed with. The 800-900 RPM right after starting indicates your AAR isn't doing its job. "my latest breakthrough was moving the vac advance line from intake mani to the throttle body which fixed numerous idle/power issues. " Some background on who installed the engine and when would help give some context. Problems from nowhere are tough to figure out.

I've only been on the site a few years but even I can see that your numbers seem all wrong. Way lean for a turbo, even lean for a performance NA. Timing is completely off, actually probably impossible to be there, the engine wouldn't start. Slipping clutch so you don't really know what power output is. You should start from scratch and confirm things like TDC, measure cylinder pressure to get an idea of CR, adjust the carb for more fuel at the critical portions of the power curve. Stuff like that. Not sure you'll get a lot of advice with what you're reporting because the situation is probably incomprehensible for the guys who do turbo. And, don't forget, dyno numbers can vary by dyno and operator. Comparing numbers is pointless.

Reorganized some phrases. Basically, your problem is that fuel pressure drops below the normal 26 - 36 psi range it should be in when off-boost. Zero means that the pump isn't pumping, there's a blockage between the pump and pressure gauge, or that the FPR is stuck wide open. Your assumption is probably off. Cavitation and heat are not a direct correlation. Vaporization is not cavitation. "Vapor lock" does not cause cavitation. Just saying, these are all relevant words, they just don't really fit what you're seeing. Forget about heat and cavitation for a while and confirm the basics. Pump power, supply to the pump inlet from the tank, etc. If the problem lasts eight hours, that's plenty of time to get underneath and do some looking and measuring.

And a bunch of MAF settings that have to be set - http://www.msextra.com/doc/pdf/html/ms3pro_manual.pdf/ms3pro_manual-140.html Pretty sure I saw that you can run on MAP and use the MAF for other things. Probably what you're doing. But it allows you to drive the car until the MAF is right. Good luck.

Don't know what manual you're using, or what your settings are, or how you wired your Q45 MAF, or what you're looking at when you say the MAF won't change voltage or registrate ariflow, but there's a ton of good information here that might help you out. No mention of a pull-up resistor. http://www.msextra.com/doc/pdf/html/ms3pro_manual.pdf/ms3pro_manual-38.html Here's page 1 - http://www.msextra.com/doc/pdf/html/ms3pro_manual.pdf/ms3pro_manual-1.html Here's a setting that needs to be changed to "MAF" - http://www.msextra.com/doc/pdf/html/ms3pro_manual.pdf/ms3pro_manual-139.html Don't have MS, of any version, but it looks like fun...

Are those Nissan rotors or aftermarket? Just looks like inconsistent coefficients of friction. Uncontrolled metallurgy. Probably averages out over a revolution though so if you can't feel it, no matter.

Acetone is a solvent for plastics also. Stay away from any solvent, even carb cleaner might mess it up. A light oil would work. Vegetable oil, olive oil, the oil in WD-40. It will soften the glue so it can be wiped off. Since WD-40's proven, that would be the way to go. Alcohol's probably safe also. Don't rub too hard, you can scratch the plastic. It's soft.

It's been documented that too much flow from the back of the head back to the pump inlet (the typical bypass that people do when they get a leak in the cabin) reduces overall cooling capacity. It reduces flow through the head and thermostat and back to the radiator. A short circuit, effectively reducing pump output. You might try clamping your heater core line closed and seeing what happens. Maybe your new core flows more than the stock system. If it has an effect, you can restrict flow through the core to improve cooling but still have heat.

The thermostat does look suspect. I had an old thermostat and it would do the same, even though it looked fine when tested in a pan of hot water on the stove. No flow there though. It allowed a wide range of temperature, about 170 to 190, and moved up and down with engine use and daily temperature. Bought a new Nissan brand 180 degree unit and it's very steady now, hits the number quickly (actually about 185) and sits there. Might rise 5 degrees on a hot day after some use. Using an inexpensive parts store Murray brand radiator. Stock NA engine.

What "blew"? Looks like you're shot-gunning "upgrade" components. A targeted approach might be better.

Don't forget the two "CV" joints (tripod-tripod or double offset-birfield, whichever, the joints in the two back driveshafts), and the splines in the diff that couple to those shafts. If you add up all of the movable joints and couplings on the way from transmission to wheel it's easy to see why everybody has some degree of clunk

How do the insides look? New bearings and seals won't fix differential wear. Maybe it's just worn out. A better gauge of "play" might be to have both wheels locked with the parking brake, and turning the propeller shaft by hand, with the transmission in neutral. Your videos show movement, but don't show that the other stuff isn't moving. When you turn the wheel, the propeller shaft could also be taking up play in the transmission, for example. This is a 300ZX right? So the typical S30 diff mount and/or loose strut mount issues won't apply.

You could be done by now if you learned how to use that meter. With a meter you don't look at the parts you look at what they're doing. Shiny new cables don't matter if the battery post is covered with a thin layer of insulating corrosion. Test resistance from the positive post to the fitting, from the post to the starter lug, from the negative post to various ground points (block, body, starter body, etc.). Just look at the numbers on the meter and fix the things that are wrong. It's very fast. If you look at old wires, and crusty old parts without testing them you'll just end up replacing a bunch of stuff that was fine and probably creating new problems. "using multimeter" will get you a bunch of tutorials on the Google.

I only watched from :30 to 1:30 but noticed that both stumbles were after you had just turned left. Typical of fuel sloshing away from the pickup tube in the poorly baffled 280Z tanks and happens to everyone below about a quarter tank. Probably worse in a 260Z tank designed for carbs. If you have a hole in the pickup tube it can happen with even more fuel in the tank . And the fuel pump noise rising and falling with the turn signals is just a voltage issue, with the low output of the alternator at idle. Mine does the same and I have pretty good output. You can make the same noise by turning your lights on and off or flicking the fan on and off.

What you wanted to do was check for power to the coil with the key on. You're not getting much value from the meter if you only checked resistance on two coils. Looking back on the complete saga, it wouldn't be a surprise to find that you just have dirty/corroded battery cable connections.

There's good stuff here - http://www.wolfems.com/downloads.html It looks like the 3D has its own ignition drivers (ignitors). There are instructions on using a locked distributor also, as input for the ECU, but they're not the clearest. There might be more details, I only looked at page 14. http://www.wolfems.com/downloads/installation-manuals.html Ron Tyler used to be a distributor for Wolf I believe. You might send him a PM. But I'd read through the 3D instruction manual first, just for a solid point of reference. Doesn't seem like you've been in there yet. The Megasquirt stuff will probably help with understanding the concepts but the details for Wolf will be different. I get the impression that Wolf products are not really user-friendly.

Looks early to be having any real discussion. There's potential. The wheels seem a bit big.

Pretty sure everything is short-nose by 1991. Your 260Z has a long-nose. You'd need to fabricate mounts or buy a kit. It's not a bolt-in.

Post some pictures here so people don't have to sign up for another forum they'll only visit once.

What you described initially is also somewhat typical of having ignition timing too advanced. Have you checked timing? Could be that your breaker plate is stuck advanced, or sticking occasionally. It starts when it frees up, doesn't when it's stuck. The breaker plate moves for vacuum advance. On the dead engine after the coil swap - where's the meter? Super simple to check for coil power, solenoid power, starter cable power, etc. You're not doing the basics of problem solving. You can even do the meter checks with a beer in hand.