2nd Gen Tacoma 4.6 V8 1UR-FE and GX powertrain Swap

I was just referring to the stock one rather than the GX. Only thing I’m not using from it is the ac compressor on/off button.

 

How are you solving the rpm and cool temp pwm signals?

 

That’s why I’m replacing the normal “ac” button with a dummy push button switch to manually activate the compressor relay. The Holley has a switch to disengage the relay under high rpm. Thinking about just leaving it at this, but someone @Dm93 posted a temp controller I might try to integrate too. Or maybe it would be easier to feed the amp RPM and ECT. lol.

 

Can you guys tell me the difference between the Tacoma AC compressor and why it has this line on the diagram? Is the lock sensor some how connected to the magnetic clutch?

Tacoma:


Gx460:

 

Use this information at your own risk but at a high level I think it is an accurate overview. I would ask for feedback though from the experts. Validation from someone more hands on than me would be ideal. I'm nucking futs about your project and hope I can help in some small way. Good Luck.

The magnetic clutch is a device that engages and disengages the A/C compressor from the engine pulley by using an electromagnet. When the A/C is turned on, the A/C amplifier sends a signal to the magnetic clutch relay, which then supplies power to the magnetic clutch coil. The coil creates a magnetic field that attracts the clutch hub and the clutch plate, which are attached to the compressor shaft and the engine pulley, respectively. This causes the compressor to rotate and compress the refrigerant in the A/C system. When the A/C is turned off, the power to the magnetic clutch coil is cut off, and the clutch hub and the clutch plate are separated by a spring. This stops the compressor from rotating and reduces the load on the engine.

The A/C compressor lock sensor is a device that detects the speed of the A/C compressor and sends a signal to the A/C amplifier. The A/C amplifier compares the compressor speed signal with the engine speed signal, and determines if the compressor is locked or slipping. If the compressor speed is too low or too high compared to the engine speed, the A/C amplifier will turn off the magnetic clutch relay and stop the compressor from running. This is to prevent damage to the compressor and the A/C system due to excessive pressure or overheating. The A/C amplifier will also flash the A/C indicator light on the dashboard to alert the driver of the problem.

Therefore, the magnetic clutch of a second gen Toyota Tacoma is connected to the A/C compressor lock sensor through the A/C amplifier and the magnetic clutch relay. The A/C amplifier controls the magnetic clutch relay based on the signals from the A/C compressor lock sensor and the engine speed sensor. The magnetic clutch relay controls the power supply to the magnetic clutch coil, which controls the engagement and disengagement of the A/C compressor. The A/C compressor lock sensor monitors the speed of the A/C compressor and reports any abnormal conditions to the A/C amplifier.

 

So, it looks like that highlighted line would be providing power to the lock sensor when the magnetic clutch signal is also hot. But not sure what that does.

I see why you are confused. This is an odd one.

 

Happy Thanksgiving Denis! This has been my favorite thread to follow for 2023! Looking forward to seeing the finished project!

 

Happy late thanksgiving to everyone. Sorry I haven't been updating for a while but I did get the AC lines figured out. I still need new clampshells and O rings. This was a major pain to weld the new tacoma fittings on the lexus lines. Everything clears with the exception of my placement of the SAIS pump lol. I will likely have to elevate it to make the hose clear the AC line.

 

Christmas update?

 

Hey Guys,

I am back, sorry I got side tracked and overhauled a 1UZ for my boat. Well I ended up buying @Braddman 's module that will make the PWM coolant signal. I am very happy that I could just buy a unit instead of making something to emulate the coolant temp signal. I am in process of getting it wired up. On another note, it appears that the AC compressor LOCK sensor signal on both cars are the same or at least it appears to me, can one of you guys confirm it?

To connect the lock sensor I was thinking to do this

Tacoma AC amp - (A14- 3) SG and splice in GX ac amp wire (G13-13) SG-2 to also keep the thermistor.

Tacoma AC amp (A14-6) LOCK and connect it to (G13-8) LOCK

Tacoma AC amp MGC (A14-21) and connect it to GX ac amp wire G13-20 (MGC). Looks like this one is a ground wire that actuates the magnetic clutch relay.

Also @Jeff Lange thanks for the heads up about "Tacoma A/C Amplifier A14-22 (IGN) signal can be grabbed from pin G45-29 (TACH) on the GX460 Engine ECU." which I found yesterday on the GX ecu and did precisely what you said.

What do you guys think of this?







Also here is the 1UZ I overhauled. Cleaned all the sludge/carbon, lapped valves, new piston rings and shes making around 180 psi on each cylinder. New oil pump, water pump, timing belt kit and seals.

 

Okay I wired it up like I described above. I also wired ACT and AC1 directly from GX ECU to Tacoma AC amp (there could be a voltage discrepancy here which may be contributing to AC clutch not kicking on). Everything works including the AC light on the button but the AC clutch is not engaging. However I don't have any refrigerant in the system yet. I don't know much about this system but I suspect the pressure switch will prevent it from kicking on if there is no pressure in the line. I am waiting for the new o-rings and pipe clamps to come in the mail. But man it was satisfying getting hot air into the cab today and the blender servo works on all selections now.

Would the pressure switch prevent the AC clutch from engaging?

 

Yes, you need around 40 psi to close the switch.
You don't really want to run the compressor with the system empty anyway.

 

Perfect, that makes me feel like I am on the right track. I will install new rings and fill it with some oil and refrigerant sometime next week. I am so excited because once this is completed, the dashboard is going on for final assembly!

 

This was difficult to stuff in there without anything interfering. Also I got an email today saying that my AC pipe clamps are on backorder, awesome. I guess it'll be a waiting game and I'll work on other stuff on the laundry list.

 

Hey Guys

These are the wires that I straight across connected to the Tacoma wires with the same functions and everything works. I couldn't figure out why the DRLs were not coming on until I remembered that on my GX470 it wouldn't kick on the DRLs until you disengage the parking brake. Today I tried that and it the DRLs came on lol. The only issue is that the GX is wired up to run the high beams and low beams simultaneously. It is not a problem for me because I plan on retrofitting projectors so that works out nicely. Running both filaments could melt your housing, I don't recommend it. All functions work now: low beam, high beam, DRL and DRL turns off when the blinker is turned on which has no hyperflash. Also I wired in the corner light on the DRL circuit.









The 2nd issue I need to overcome is that I am getting a B2424 and B2425, Right and Left Headlight Beam Level Control Motor communication is lost. I suspect this is also triggering a "Check headlight system" message on the gauge cluster.

Do you guys think I could I get this message to go away by soldering in a 10 kΩ or higher resistor in between LH A46-30 and ground / RH A46-11 and ground?

 

I wonder why Toyota considers this only a 2015 TSB, when the trucks are the same...

Always noticed my 08 is not that cold (A/C) when outside temp is high
even though R134a is in spec

I guess this is why
Makes sense. Every other car has 2 electric fans, with one or both kicking on with A/C on.
I don't see how radiator fan running directly off the engine would have that same amount of control or added airflow of a second fan.

 

I ran into this problem last summer while on the trails with my clutch fan. Over 100 degrees outside and the engine was running a little hotter than normal and the AC wasn't blowing cold at all at low speeds. I swapped to a custom dual 13" Spal fan setup with a Derale PWM controller and AC blows cold at any speed with better than normal engine temps. Didn't really have to but I upgraded the charging system with a 250a JS alternator, 1GA Big 7 wiring and an Odyssey AGM bat. Best mod ever.

 

that sounds like a better solution than the TSB kit that people are reporting only gives them a difference of 3-4deg and didn’t feel worth the $600 for the kit not including recharge R134A which is only really convenient if you happen to work at a shop with an A/C machine to tinker around on an off day.

 

Don't mean to hijack the thread but that TSB is a joke. A single tiny 8 or 10in fan blowing on a small section of the condenser. That's why the small difference. My mod pulls on the entire radiator and condenser.

 

TSB’s usually are. Theres a recall, I shouldn’t say what brand or model. Water leaks onto an important computer. You know what the recall is? Put the computer in a sandwich bag.