GeneralDisorder

Thermostat change on a computer controlled engine will only confuse the computer and potentially create codes. The ECU isn't going to run the fans till it hits 204 regardless of thermostat. GD

He's dead Jim.

Hello? McFly? I said YouTube.... search. Like a million videos on this. GD

Yes in all likelihood this will end up being related to aftermarket $hitty wiring. Things like this almost always are. Definitely a good idea to look that junk over. Barring seeing the problem there, the idea is to verify power and ground leads to the ECU and then trace back if they don't exist. GD

Could have been related to the coolant/ATF mixing issue and radiator replacement. Maybe they were original but it had still been overheated causing the damage but not a fire ring breach. GD

The ignitor on the firewall is the transistor(s) that switch power to the coil pack to fire it. Just match up a few wire colors with numbers and you will soon get a picture of the numbering scheme. It should take no more than identifying colors of each corner wire and the wires adjacent to them then determining the pinout numbers from there. Ignore the labeling on the connectors. GD

This is definitely chain cover pull. That sucks. GD

Make your own with urethane. SuperPro might have some EA bushings.... still easier to get some smooth-on two part urethane and make a cardboard form. LOTS of YouTube videos on the process. GD

Replace pistons with 1999 to 2000 SOHC piston. Head gaskets with Subaru 770's. Not if, but when. GD

Nope. Definitive diagnosis. Replace head gaskets. Or don't and continue to deny the reality. Matters little to me. GD

Then most likely the damage was from a prior head gasket failure before your ownership. These can suffer quite a bit of damage and still run seemingly ok. GD

Well one may be the harness connector pinout, and one may be the ECU pinout. They are going to be mirror images of each other. GD

It's a 95 ECU. They are the only ones with gray connectors. Here's the pinout (took 30 seconds to find this with google): http://busaru.com/attachments/article/116/1995%20Legacy%20Pinout.pdf GD

Optima is junk now - sent production to Mexico. LOTS of stories of premature failure in recent years. Terrible quality control and they switched away from pure lead to lead alloys. Crap IMHO. Odyssey is where it's at. They (Enersys) designed the spiral core that optima uses and their new flat plate design is 15% more dense. Their design life is 12-15 years. GD

Exactly. The reading when the head gaskets were blown is meaningless. Be concerned if it gets to 240 or above (without blown head gaskets and full on coolant). @ 16 psi system pressure, 50/50 mixture will not boil till 267* F GD

It's there in the manual. You just have to look harder. GD

Yeah I still think you need to try jumpering the ignition switch circuit so that it is sending power to the hot in start/run circuit all the time then try cranking it. Also sometimes with these ignition switches.... turn it very slowly till it just barely touches the start contacts. Don't push hard on it, and it might work. The connector pinout is in the FSM you can download from sl-i.net.... GD

You need to stop troubleshooting with Visa. Check all the power and ground supplies to the ECU. I really think you should check valve timing. My bet is that it has slipped time or broken the timing belt and the cam/crank reference pulses are not synced or don't exist. GD

Yeah it's not too much of a concern really. My Trans Am originally had the fan set points set to 222 and then didn't kick on the secondary fan till 243. Higher temps result in more complete combustion and fewer hydrocarbon emissions. One of the MANY reasons these engines have always needed synthetic. Amsoil synthetics can handle sustained 350 degrees with no damage. Definitely do run a 5w40 though. Viscosity decreases with temp. I run nothing but 5w40, 10w40, 20w50, or 15w50 depending on stock, modified, season, etc. GD

Put a 90 bend in it, and attach it to the carb mounting stud. GD

Phase 1 includes the dual cam engines like the EJ25D and they do NOT share intake patterns. Phase 2 is entirely different, turbo's are different, and besides that due to entirely different idle control systems you can't interchange any of the manifolds easily between phases anyway as the manifold must match the heads but also the ECU's preferred idle control design. GD

No

Correct - the small lead that runs to the PCM comes directly off the 10 AWG solenoid wire. But it's an internal splice inside the harness and as Fairtax mentioned it is completely inaccessible, buried behind the dash. I doubt you have a fuel pressure issue - the PCM has no knowledge of fuel pressure and would continue happily pulsing the injectors without any fuel at all. What you seem to have is either a slow cranking speed coupled with no start signal to the ECU, or a loss of 12v to the ECU. Did you say that you had solid 12v at the injectors? As for the ECU start signal.... they will eventually struggle to life without it if you turn the engine over fast enough, but the ECU gives additional fuel and changes timing to allow the engine to easily start at the ~300 RPM cranking speed. Without that signal, it may be difficult to start and the slower it cranks the worse that would become. Also typically harder to start when cold as the ECU's only inputs are crank and cam signals and without the start signal it just starts seeing engine rotation - it may not idle up and provide cold start enrichment. GD

If the top is rounded then it's likely either a nylon insert locking nut, or a tri-lobe nut that has punch marks on it where it creates friction on the threads. Put some blue thread locker (242 or 248) especially if it's being reused. GD

I would have to consult the diagrams. Download the manual here: https://sl-i.net/FORUM/showthread.php?18087-Subaru-Factory-Service-Manuals-(FSM)-Every-Model-USDM-EU It is not sufficient to just turn the starter - the ECU also needs a 12v signal from the starter solenoid lead telling it you are cranking the engine. GD