Hi, I'm Ben and new to Fort Worth, Texas. In the near future I will install a new ACD/AYC Pump on my Evo X, and I'm wondering if anyone in the area might be willing to lend a hand or learn with me.

Does anyone local have DIY experience bleeding the ACD/AYC System? My best option seems to be build or buy a tool that will drive the pump and solenoids directly. Should the EvoScan MUT III ACD/AYC Actuators work on an Evo X? I didn't have luck with the MUT III EvoScan actuators, but maybe there's operator error or something wrong with the ACD/AYC ECU?

 

How did you manage installation of new pump ?

 

Did you try turning on the key and flooring the gas pedal? This method works on the 8/9, you just have to repeat it over and over again

 

Howdy,

DIY PUMP REPLACEMENT:
I replaced the ACD/AYC pump and bled it using a 12V controller with switches to power up the pump and actuate the solenoids. I built pressure, opened solenoids, and bled the ACD, AYC left, then AYC right. I bled each valve until I had flushed the system and no air bubbles were present. This is similar to flushing and bleeding a brake system. I repeated this procedure three times while driving the car in between.

NOISE ISSUE:
There is a "clank" noise up front as the system pressurizes on startup. I know it's the ACD/AYC System causing the noise, because don't hear it with the system disabled via removal of the ACD/AYC relay. Perhaps the pressurizing clutch packs make some noise, but this isn't anything I've heard before the replacement.

I figured the "clank" noise must be the result of my own ineffective bleeding of the system, although I was very thorough with my approach.

DEALER EXPERIENCE:
I scheduled an appointment with a Mitsubishi Dealer to bleed the system and diagnose the "clank" noise if their bleed procedure didn't resolve it. I explained the "clank" noise and that I had just installed the pump.

The dealer ran the procedure. The technician said no air came out of the system when he bled, and the "clank" noise was not present anymore. That seems odd that no air came out, not even a bubble, but ok. When I started the car for the first time, the "clank" noise was present. I confronted the service adviser about the presence of the noise, and he said they need to have me drop the car off another time to diagnose.

MY THOUGHTS:
- How do I diagnose the noise?
- The MUT III Bleed procedure used less than 1/5 a quart of ATF. Is that normal?
- The MUT III Bleed procedure didn't get any air out of the system. Is that normal?
- The MUT III Bleed procedure resulted in an overfilled reservoir. (probably 1/5 a QT).
- Does anyone know what the MUT III AYC/ACD Bleed procedure does?
- Is there Shop that doesn't have a "middleman" called a Service Adviser?

I tried to watch the procedure, but missed the initial part where they bleed the ACD at the TC. They were bleeding the rear AYC already when I started watching. The service notes just say they bled the AYC system. The Service Adviser insisted ACD was also bled, but he wouldn't confirm with the technician. I wonder if the procedure is unclear and they might've missed the ACD bleeding? I will have to look at the service manual.

Any suggestions would be helpful. Thanks.

Cheers,
Ben

 

I didn't even attempt this, because I wasn't sure if it worked with the AYC as well.

 

Sounds like you already had the system bled which is why no air bubbles cane out, and also why they didn't have to use much fluid. Sounds like the tech slightly overfilled the reservoir which is pretty common and not really a big deal...use a suction pump to remove the excess if you want, but unless its actually overflowing I wouldn't worry about it.

 

Thanks for the response...My thoughts exactly. I just felt like I was missing something if nothing was bled from the system, yet the noise issue was resolved; what changed? I haven't driven much, but I've noticed less noise on subsequent startups. Perhaps its just working out some kinks.

With regard to the amount of fluid used: A pump replacement would introduce air at the acd/ayc hardlines and reservoir lines, so I'd expect they'd have to flush more fluid through the system to effectively get air out from those points. In my circumstance the lines were bled already and its not an issue, but if I had just replaced the pump without bleeding myself I'd be concerned.

The tech did good work and was helpful with all the questions. The service adviser just didn't show interest in answering questions or helping me understand my options to address the noise.

Cheers,
Ben

 

Had you not already bled the system, they would of had to push more fluid through, but since you had, no point in wasting new fluid.

 

That's logical of course They made an assumption that it was bled. I don't usually give the dealer folks that much credit.

I'll have to find a track day or autocross to test it out.

 

I don't think is was as much of an assumption as it was an observation.