Guys I really need your help with this problem. It seems I’m missing something…

Car: Evo VIII RHD (UK) converted to LHD

Problem: ACD pump not activating by pushing throttle pedal with ignition on

So when I put the ignition on and floor the throttle pedal, the ACD pump does not activate. However there is also no error on the dash. A single light stays on and is switchable through the ACD button.

I tried several things like flooring the throttle pedal and then switching the ignition on, keeping the pedal floored for 1 minute.

I checked all fuses and relays, I even switched the ACD ECU with another one, switched the relay with another one. All without any success.

Also when putting the ACD ECU in error reading mode, it gives no errors (on both ECU’s)

I measured the throttle sensor wire @ ACD plug side. This perfectly gave good readings of 0.8v – 5.01v. Then I shorted the ACD ECU power supply pin to the relay pin. At this moment the pump started up. So it seems that all the wiring and power supply to the pump is working correctly. Also the ECU power supply seems to be good. I also measured the relay pin with the ACD ECU connected while flooring the throttle pedal. The ECU did not give any output on the relay channel.

I disconnected the pressure sensor connecter at the pump. The ECU immediately responded by lighting up the three ACD lights and giving the open circuit error.

I have the feeling that the ACD ECU is not receiving some kind of signal so it does not activate the pump with the throttle.

Does anyone have a clue why the ACD ECU does not activate the pump?

 

I personally have no Idea. Most guys however just remove the pump and T case and throw on a non ACD case. They have less problems cause there are less moving parts. ACD is nothing special any ways.

 

The folks who do this/say this are straight line folks or just aren't sensitive enough to detect the differences between an ACD and non ACD setup when doing non straight line things at speed.

On topic: Not seeing anything else easy....maybe the wiring itself is shot somehow?

 

I took all measurements and it seems that all signals are reaching the ACD ECU. Does anyone know if EVOSCAN now finally works with reading the parameters live? Or does a MUT-III give live readings of all data received by ACD ECU?

 

if you have a proper cable you can log the acd ecu with evoscan, yes..

 

Can confirm this. I had my ACD pump off the car for about a month because it stopped working and I got used to the open diff feeling. Finally got around to restoring the pump and installed it back on the car and instantly noticed the difference in steering input feel.

 

I'm curious, what's the difference?

 

Felt like there was slightly more weight to the steering feel and when taking turns quickly the turn-in felt sharper. Without the acd it felt more vague but with it I think it feels more precise with better feedback through the steering wheel. Just my initial impressions driving around town but I'm sure the differences would be much more pronounced on a track/auto-x.