SleeperZ

A bit of polish and that crank will be good as new. LOL, that's a pretty complete breakdown.

IIRC, all the turbo models had rear panels that screamed "TURBO!", without the exclamation point. Personally I'd dive right under and look for the finned diff cover.

Sure it's possible. You will want to isolate it from vibration though, that will kill a coil faster than anything.

That is just too cool. Congratulations.

Personally I would use only steel.

People get 400whp with stock pistons. Reliably, with good engine management. And forgies will not protect you from bad engine management.

Looking good. Those are some kind of crazy wheels you ended up with. Nice find, good luck with the build.

Good point about altitude. The main thing is less air resistance at highway speeds. The intake air is always metered and during cruising the oxygen sensor will maintain the right mixture, so the thinner air does not significantly affect combustion. But my high 20s mpg at 70mph have always been at 5000+ feet.

One more thought. What is the condition of your injectors? If you have one clogged it could throw off the whole engine while running closed loop as the other injectors will have to flow more to compensate for the plugged one.

Do you have an air dam? Aero effects are going to be more noticeable at 70mph. How are your tires wearing? Excess camber and toe can affect mileage by a good amount too. It's sounds like engine timing is close, verifying the advance at 3000 rpm sounds reasonable. I also used the fuel temp sensor, but I doubt that affects the fueling very much. I did not have a knock sensor, if I hooked it up, I immediately got the knock code. Unless your air filter is plugged, that's about all I have. I was on a road trip once where my mileage dropped below 20mpg, and noticed my air filter was very dirty. Replacing it immediately restored the mileage.

The Supra injectors flow twice the L28ET units flow. You will not be able to drop the fuel pressure enough to make them run acceptably, and if you do, what will you have gained? You will not get more power unless you increase air AND fuel and you are not proposing changing either.

I never ran an MSD, I used stock Z31 coil and ignitor, using the ignition coil wire. But that is the correct signal to use for an MSD, whether the MSD can use it I do not know. You need the FACTORY service manual for a Z31, not a generic repair manual (although they may have wiring diagrams, I bet they will be difficult to see the model year differences). These are year specific. You may be able to find .PDF versions of these like the S30 manuals.

Believe me, mine was not setup incorrectly. An incorrect set up will not return 50% better economy and normal driveability. We are not entirely fact-free; fuel economy may be dependent on many variables, but it is not black magic. However, I agree, more information is needed, especially ignition timing and tire size and inflation. Those are critical, as well as a good clean air filters.

I understand, but it seems to me the idea is not to start modifying the system away from factory but to find out what is wrong, since the factory setup is capable of delivering the appropriate economy.

No tricks, no codes, no emissions controls, I regularly got 29 mpg at 70 mph - Z31 ECU, stock L28ET in my S30. If you get 20 mpg under similar conditions there is something not being accounted for. That's 30% low.

1. There are differences in pinout for some of the sensors. When I wired one, I got the diagram from the service manual for the specific model year of Z31. Before the internets there was the library, that's where I photocopied the reference material. 2. Shielded refers to metal overbraid that protects sensitive signals from interference from engine noise like spark events. 3. You don't need to hook up the tach, it is separate from the ECU. As a matter of fact, my tach never operated properly with the Z31 ECU. You do need to hook up an ignition wire from the ECU to the coil driver (ignitor) so the ECU can drive the coil.

Same here, if the ECU and engine are running well, this is appropriate fuel mileage.

I thought the injectors were set to a specific ON time while cranking, not %, 2mS (2 milliseconds) would not be unusual. What are the parameters you set for PWM? On time, %, and frequency IIRC.

If it's not running, you are not burning any fuel, making any AFR measurement completely useless. AFR is only relevant when the engine is running. Since you are getting fuel out of the injectors, I would speculate your ignition timing is off by a whole lot.

I'm confused. The engine is not running, how do you have or measure an AFR?

What are your symptoms of "not running"? Just crank with spark, and no firing? Check crank timing, make sure injectors are wired right and get pulled to ground while cranking.

The resistors you use depends on which injectors you have. But you can forego resistors even if they are low impedance. You should be able to use the PWM feature so you get the fast opening without the extra power dissipation.

Personally, I think you found exactly the right balance, it looks amazing.

Nice find, I'd jump on that in a heartbeat.

Wow, that's got to be it. 10.7 on an NA L6 is ridiculous. I was impressed with Norm the SU dude running 12s on the NA L6.