Hi all,
I've got a 1UZ fitted into a 1970s Lotus, the 1UZ is from a 1992 Soarer with the three pin ECU (40-40-40 plugs).
I have air conditioning and it works well. However when I did the wiring on the car I didn't have any solid information on the aircon wiring for the ECU, so I just made the aircon control manually switched by the aircon button on the heater panel, and a temperature sensor in the cabin to turn it off when it reaches the target temperature. So the ECU does not know when the AC is on.
There are two pins on the ECU that seem to be concerned with the aircon. I wired these from the from the ECU pins into the connectors behind the dash.
- E9 connector pin 23 - white wire - called "AC MAG" on the Toyota wiring diagram
- E9 connector pin 34 - blue/red wire - called "AC" on the Toyota wiring diagram
I have two things I'd like to fix/change:
1. When I engage the aircon the RPM drops at idle by about 200 rpm. to compensate I have raised the idle speed a small amount, but it would be better if the ECU maintained the idle speed
2. When going to full power I can manually turn the aircon off, but it would be good if the ECU could decide to turn the aircon off during periods off full acceleration (lots of ECUs do this)
But I don't know how this works on this ECU - does anyone know how this is implemented in the 1UZ Soarer ECU?
For example if the "AC" is an input that I should put 12v on when the aircon panel control is switched on, I can test this by putting 12v on the blue/red wire and seeing if the idle speeds up (assuming that's what it does)
And if the "AC MAG" is the output to the aircon relay that drives the mag clutch, I can test this by putting a bulb to ground and seeing it comes on and off while doing some test driving, then i can wire this output to the aircon mag relay in place of the direct wire from the aircon switch on the heater panel.
But I don't want to muck about with it, not knowing how it works - the car runs well with no error codes, and I don't want to damage the ECU by guessing.
Any suggestions or help appreciated
Thanks, Mat.
I've got a 1UZ fitted into a 1970s Lotus, the 1UZ is from a 1992 Soarer with the three pin ECU (40-40-40 plugs).
I have air conditioning and it works well. However when I did the wiring on the car I didn't have any solid information on the aircon wiring for the ECU, so I just made the aircon control manually switched by the aircon button on the heater panel, and a temperature sensor in the cabin to turn it off when it reaches the target temperature. So the ECU does not know when the AC is on.
There are two pins on the ECU that seem to be concerned with the aircon. I wired these from the from the ECU pins into the connectors behind the dash.
- E9 connector pin 23 - white wire - called "AC MAG" on the Toyota wiring diagram
- E9 connector pin 34 - blue/red wire - called "AC" on the Toyota wiring diagram
I have two things I'd like to fix/change:
1. When I engage the aircon the RPM drops at idle by about 200 rpm. to compensate I have raised the idle speed a small amount, but it would be better if the ECU maintained the idle speed
2. When going to full power I can manually turn the aircon off, but it would be good if the ECU could decide to turn the aircon off during periods off full acceleration (lots of ECUs do this)
But I don't know how this works on this ECU - does anyone know how this is implemented in the 1UZ Soarer ECU?
For example if the "AC" is an input that I should put 12v on when the aircon panel control is switched on, I can test this by putting 12v on the blue/red wire and seeing if the idle speeds up (assuming that's what it does)
And if the "AC MAG" is the output to the aircon relay that drives the mag clutch, I can test this by putting a bulb to ground and seeing it comes on and off while doing some test driving, then i can wire this output to the aircon mag relay in place of the direct wire from the aircon switch on the heater panel.
But I don't want to muck about with it, not knowing how it works - the car runs well with no error codes, and I don't want to damage the ECU by guessing.
Any suggestions or help appreciated
Thanks, Mat.
