Hello guys
I may have a potential solution to the MIL problem, but did not have time to test it out, so if you guys got some time... and a couple of 80s laying around, you can try it out.
Long story short - my dad and I changed an H150f into his 97 TLC80 and of course the MIL light when ON for a couple of things during idle in the driveway... a DTC for missing ATF temp sensor, 3 for the missing solenoids and one for the speed sensor (number 2) on the output shaft of the transmission.
OK, so we unbolted the oil temp sensor and plugged it in the connector, and as expected that DTC (P0710) ghosted.
We attached the output shaft speed sensor and that DTC (P1700) also bit the dust.
Then we attached the solenoids and DTCs P0753, P0758, P0773, which signify basically missing solenoids, also turned OFF the lamp.
We were aiming to find everything necessary to imitate the scenario of the car rolling downhill in neutral as that scenario doesn't light up the MIL.
The MIL light never went ON, but once we started driving the car, it lit up. But this time the DTCs that showed were only 3 for malfunction in the solenoids or something in that system. The ECU just compares RMP of engine and RPM of speed sensors 1 and 2 and says sorry but things dont match.
On the electrical diagram for the ELECTRONICALLY CONTROLLED TRANSMISSION, the neutral signal from the PNP switch seems as if it's not used by the ECU, but in fact it is - it is the NSW wire on pin 22 of E7 connector and is a +12v signal directly from the ignition key and has nothing to do with the PNP switch on the side of the transmission.
One very helpful table about the behavior of the AT, is the table that shows electrical signal combinations that tell the ECU what gear it is asked to activate. What I found was that the ECU judges that the car is in NEUTRAL when no +12v signal is sent to either of the three gears (R, 2 and L) and the NSW pin 22 on the E7 connector. Simply removing pin 22 from the connector to prevent the +12v signal from reaching the ECU, isn't enough to make the ECU think that the AT is in neutral.
From another Toyota document (in the description for the DTC 1780 for ENGINE diagnostics, not ECT diag), we found that that same signal on PIN 22 of the E7 connector, is in-fact dual signal pin. When the car is driven, it receives +12v, but when the car is in NEUTRAL, +12v is cutoff and it is grounded thru the starter circuit (Pin 11 of E7 is also grounded thru this wire). So either you have to depin the original wire and attach a different wire with a pin and splice the other end of the wire into the ground wire of the ECU, or you have to bridge pin 5 and 6 to be in NEUTRAL. If you want you can remove the speed sensor signal number 1 (back of transfer case) from the ECU connector (pin 8 of E7) and viola - no more CHECK LAMP!
But hey...that's not all!
When you start swapping the MT in, what's the first safety thing Toyota tells you - remove the negative terminal from the battery. Well, by the time you realise what culprit that is, you probably have already installed the MT a couple of times and now you're sitting and wonder why the MIL is ON!
The prior initialization is lost from memory and that ECU will never complete its tests for it to become ready to pass inspection... because it has to check how the now phantom AT is changing gears with solenoids that are also ghosts!
So here comes a "relatively" simple solution for which you will need... a buddy with his own Land cruiser 80 in original form.
What you are about to do is to Frankenstein your ECU - give your ECU a separate power source to keep in memory the initialization test results long enough to be transfered to your own car, after it has been in your buddy's car and driven with for awhile.
On your ECU:
You take a 20 amph or so +12v battery and wire it in on the ECU as a separate energy source. Remove the cover and attach positive wire on pin 2 of E7 connector on the inside of your ECU (where the original EFI fuse keeps the ECU memory) and negative wire on pins 13, 16, 26 of E4 connector also on the inside (the three brown ground wires).
Attach a 15amp fuse to the positive wire to simulate 15amp EFI fuse for safety.
On your buddy's Cruiser:
Make a pigtail for your buddy's car - a decent diode with separate pins on each end - one for the depined pin 2 from E7 but male, and the other same as the depinned pin and attached to the connector. Use this pigtail as a block so to prevent current from going back into your buddy's car's system and powering the cars electrics in reverse.
Then take the ECU and plug it inside your buddy's TLC that has it's ECU removed and drive around until the diagnostics show initialization test complete. Then simply replace it back into your TLC and NEVER remove the negative terminal on your battery or the EFI fuse, unless you want to do this demolition devil trickery again!
The buddy's TLC should be free from problems. The check engine light should be OFF with no known malfunctions. And most importantly... a buddy willing to depin pin 2 from E7 and attach a pigtail with a diode, so not to cut it his original wire.
I am unable to try this as I am not near the car anymore and wont be for a long time.
Let me know if anyone wants to attempt it.
Should take a couple of hours.
Also on separate note - the main clutch cover throw-out bearing is different if you use the H150f (33030-6A420) from TLC 78/79 and also the slave clutch cylinder is also different. Part numbers are 31230-60181 for the bearing and AISIN (31470-60230) for the salve cylinder. You'll need transfer lever retainer base 36344-60040.
We had to move the rear mount support forward which was a bit of a custom job. The frame has openings but no nuts welded so you have to play around with it.
And lastly the rear prop shaft is lengthened and front prop shaft is shortened or you can use one from Gen3 4Runner.
The rest of the swap is mentioned in other threads.
