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Guest |693|

Mazda RX7 S7-8. DI 1 AirCon request not accepted

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Guest |693|

Hi!

Mazda RX7 1998 w Vipec PnP

Vipec ECU will not see DI1(aircon request) when switched on.

AirCon works w stock ECU.

Voltage @ DI1, pin 4V(measured between gnd & pin 4V) is 1.2V w AC switched on.

This is due to AC request beeing fed through blower motor resistor and a diode(0.4V over resistor & 0.6V over diode).

If I bypass the diode Vipec will recognize the signal(0.4V) but 1.2V is to high.

How do I solve this?

Regards

Marco

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This problem is resolved on some of our other plug in ECUs by placing diodes in series with a resistor to lower the DI voltage. Each diode will drop around 0.6V. Your ECU already has the resistor on the bottom board, so only a diode needs to be added. If you put one diode in the wire to pin 4V the problem should be resolved. Put the stripe end of the diode towards the ECU. Pretty much any standard diode will do (eg 1N4148 or 1N4007).

[attachment=0]AC on DI.JPG[/attachment]

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Guest |693|

Hi!

In the picture 2 diodes are installed? Is this correct?

Tried installing one diode and it helped a little bit, with fan in pos one Vipec D1 will recognize AC on but @ higher fan levels the voltage @ pin 4V goes over 1v and DI1 shuts off.

Marco

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Guest |693|

More questions........

When AC button is off voltage @ 4V is approx battery voltage.

When AC button is on voltage @ 4V is approx 0.6V w diode connected.

When AC pressure switch(in series w AC button) is open due to high pressure, voltage @ pin 4V is 0v=gnd.

This means that Vipec ECU does not understand that AC systempressure is to high and just keeps running the AC compressor.

How is this supposed to work?

All i now is that w stock ECU AC button works and AC compressor starts/stops depending on system pressure(pressure switch)

Marco

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Hi Marco

We did strike this on early production boards.

Can you check the board you have has a couple of wire links on the bottom side.

If you do we will have to do some more investigating.

I would also suggest avoiding use of the AC in its current state as if left on the system will over pressurise and blow a hose.

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Guest |693|

Board looks like this.

Can you send me a functional board today? Have already spent 15hours to work out these AC issues which i probably will have a hard time getting paid for :(

Regards

Marco

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Hi Marco

The board you have is current. The catch is that even a replacement board will have the same problems.

Do you by chance have a pin out for this car or know all the AC pins and their function.

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Was this problem solved at the end? I am having the exact issue with Link G4+ plug ins on my FD.

"When AC pressure switch(in series w AC button) is open due to high pressure, voltage @ pin 4V is 0v=gnd.

This means that Vipec ECU does not understand that AC systempressure is to high and just keeps running the AC compressor. "

 

Once the AC pressure switch 'clicks', I no longer able to turn off AC compressor, it will stay on.

It's like the pressure switch is working the opposite way as it suppose to be.

 

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