MoTeC Global Forum

Hi everyone ,

Want to clear up a problem with wiring on my SC 3SGE engine. Its summer , hot and my air doesnt work as it supposed to as OEM.
The 3 pins relevant are ACT , AC , FC



When the air conditioner is turned on the idle drops a bit but stalls after a sight rev.

Upon inspection 2 things noticed ACT and AC there is no connection to the MoTec, FC is connected to A33

Also with the OEM setup when the air conditioner was turned on the fans would come on buy they dont when connected to the M800 ?

Second thing found that there is nothing connected to the PRG purge valve



This is my set up



All i could find is the Temp activation control



This is the quote from the training manual




Last question as can be seen it the picture above the RSO idle valve.
Early on set up there was no connection( couldnt hold idle obviously ) but it was retro fitted

Am i correct that it should be connected to one of the AUX ?

We noticed that it was difficult to control at 250hz as per Toyota manual ? I believe its at 500 hz any reason for this and possible scenarios ?

All help much appreciated

Oh i should point out that on the Beams engine compared to the old 3GE's and Turbo there is no A/C idle up VSV.

The ECU must be controlling the idle valve under the Throttle Body

I own a Ford Falcon V8 where ACT is the Air Conditioning Evaporator Temperature(pressure switch goes open circuit when evaporator pressure gets too low indicating iceing on the evaporator where the ECU shuts off the compressor to de-ice: 195Kpa=0DegC with R134a).
AC1 goes to the A/C compressor solenoid on mine, which when power is applied to start the compressor, the ECU changes idle to idleUp(~100rpm increase)
FC is probably the A/C condensor fan power. I don't have a seperate fan, but the 2 main radiator fans run at low speed as a minimum.

With the purge valve, there are a number of conditions to be satisfied:

1: Closed loop lambda control
2: Steady state running(smooth RPM with only small fluctuations like on the highway)
3: Manifold vacuum- i don't know how much is needed
4: Engine temp
4: Conditions correct for 20+ seconds
Note: these are the required conditions from my workshop manual(AU2 XR8)

I'm assuming the RSO valve is idle control? My IAC(Ford's name) is 165Hz out of the manual and i found that there is a large deadband at each end of the PWM cycle. It's only useful between 10% and ~85%. The engine idles at 1000RPM at 35% PWM where 80% will give ~2800RPM, so it is quite sensative(38%=1200RPM)

Hope some of this info helps

The A/C system in the ECU needs a digital input to indicate that the A/C needs to go on/off. When this dig is on the ECU automatically switches the A/C clutch output (need one of these) and the A/C fan output (depends if the car has a sepearate fan for A/C). It will also add extra duty cycle to the idle valve if it has been setup. I would usually use some delay of 1sec or so to get the idle responding a slight time before the A/C cluctch and fan kick in.

The purge can be an output based on a table of throttle position, rpm, map, etc. We don't really have a dedicated function as no-one in motorsport has ever really asked.

Thank you for the responses.

All 3 outputs are from the AC Amplifier

I have confirmed that the AC input is to tell the ECU that the Air Con is on then the ECU to do its thing to steady the idle.
The ACT is to tell the Air Con to turn off at certain conditions that need to be set e.g above a certain position on the throttle body, hard acceleration.



Can anyone explain this , whats actually happening and what needs to be done by the M800 ?

Apparently the AC amplifier takes care of all the other duties such as
COOLANT TEMP. SIGNAL IS HIGH.
A SIGNAL THAT THE TEMPERATURE AT THE AIR OUTLET IS LOW.
A SIGNAL THAT THE REFRIGERANT PRESSURE IS ABNORMALLY HIGH OR LO

The CF is the most misunderstood pin. Its not an out put but input.
In the manual which i cant read it says



Can anyone explain this , whats actually happening and what needs to be done by the M800 ?

Its definitely related to the state of Relay No1 which is normally closed but open when ig is on



Next

Yeh i dont really see anyone having a charcoal canister on a race car but i would like it to be functional so thanks for the suggestions. Apparently the signal is 50hz and is activated by the temp conditions at the top of the page.

Next

I found out that its 244 Hz for the idle control valve. So is that the exact figure that needs to be used , not sure if it is set at that will have to check. For some reason i remember 500 Hz , what would that do ?

MANDALAY wrote:I found out that its 244 Hz for the idle control valve. So is that the exact figure that needs to be used , not sure if it is set at that will have to check. For some reason i remember 500 Hz , what would that do ?

A rule of thumb is that when the valve is at the quietest then the frequency is about right. This can happen more than twice in frequency spectrum, ie 244Hz is about half of 500Hz, harmonics. Both or some other could be usable, just test which has best response and behaviour.

Is this idle valve two or three pin model? If three then one coil tries to close and other tries to open it, and ecu outputs must be configured properly.

This is the drawing



Pin 1 RSO ECU
Pin 2 positive
Pin 3 negative

One side is grounded -12 V while the other is controlled by the ECU. This is a newer set up whereas the older Toyota set ups had both signals from the ECU

Normally for climate control systems they have an output to the ECU, MoTeC or factory. When this is active it means the ECU needs to turn on the compressor and possibly the fan. This will also control what the idle does, in most cases you add an extra amount of duty cycle to the valve as an offset to what is done when the A/C is off. To do this you just need a digital or switched input into the MoTeC ECU and configure it as A/C request. This whole system can also be told to turn off if you are at a certain high throttle range (up to the user) and also an RPM range, this save power when you want to go fast.

The A/C request is the only thing the controls the A/C to be on/off in our ECU. If there is some other logic output from the A/C unit to tel the ECU to turn off it would probably have to be incorporated in a relay (for example) to disable the main A/C request signal.

The CF....no idea, I don't read Japanese either. But again, if it is something that is supposed to override the ECUs decision to turn on/off the A/C clutch then we don't normally use it. Depending on how many inputs/outputs you still have left it could probably be made to work but I would need exact information on what you want to do.

As for the idle valve the frequency has a huge effect on the idle tuning. Basically once you have chosen a frequency and tuned the idle andy change in frequency would require a re-tune of the idle control. Lower frequencies will give a wide control range for the valve, e.g. maybe you have good resolution over 10-90% duty cycle fully closed to fully open. If you increase the frequency by a lot your low and high dead bands increase and the control will become less stable becasue the fully closed to fully open range of the valve may now be 35-65% duty cycle, this will make it harder to tune.......well much harder than it already is. I would generally try to use the lowest frequency possibly for the valve. 500Hz seems pretty high.

Thank you for the response.

So im sure with the input to the MoTec we will fix up the idle with the air on.

Maybe not having the ACT and AC connected to the M800 is opening the circuit within the A/C amplifier and not turning the fans on as they should. Will see

Here is a schematic of the internal to the ECU , are you able to explain the circuit to me ? The ACT and CF



Point noted on the idle control valve

Hi mate,
The ACT and the ATS are low side drive outputs and the CF is a switched input by the looks, pulled up to 12v, ours are only pulled up to 5v.