ACD System Issues (constant stand-by mode after number of attempts)

[Johns_EVOIXSE]

Culprit: 2006 Evo IX

Problem: ACD keeps going into stand-by mode (3 setting lights - tarmac, gravel, snow)

Attempts to rectify:

1. Reset ECU (disconnect battery)
2. Bleed ACD manually
3. Bleed ACD electronically
4. Replace ACD pump with a pump with only 13k miles
5. Swap ACD ECU since mine was tuned and it was the only thing that changed in the ACD system since two events ago. ACD worked fine for two event's after the ACD tune.
6. Checked ABS sensors for broken wires or anything out of the ordinary
7. Checked Resevior level.

Things to consider:
1. No DTC's present on Evoscan
2. Pressure switch column on data log shows 0 the whole time. Is this normal? Evo scan calls it out as a confirmation switch for high and low pressure.
3. The data log is showing a correlations between the mA sent to the center differential solenoid and TPS / Steering angle etc. But, after 30 seconds up to 2 minutes, the mA falls off a cliff.
4. Oil Pressure in the accumulator stays constant at 72 psi. Is this normal?

The data log can be downloaded here for reference:

https://www.dropbox.com/s/p4gwwany06...9_19.41.37.csv (https://www.dropbox.com/s/p4gwwany0617i5g/EvoScanDataLog_2013.04.19_19.41.37.csv)

Questions:
1. Has anyone had an ABS sensor fail without it throwing a code?
2. Are the differences between the wheel speeds on the data log normal? Is there a plus/minus tolerance that it needs to be in so it doesn't throw off the ECU?
3. Are there any relays associated with the ACD?
4. Is there something I'm overlooking?

Thanks in advance. I appreciate any feedback on similar issues.

[ebevo]

bump for you and subscribed to know the outcome

[HMatt]

Have you noticed any leaks under the car? or have you attempted to drain any of the transfer case fluid?

[Johns_EVOIXSE]

Have you noticed any leaks under the car? or have you attempted to drain any of the transfer case fluid?

No leaks under the car. The resevior was full. Forgot to add that to the list of things I checked.

What are your thoughts on flushing the transfer case fluid? Fluid was flushed just prior to the event when it originally happened.

[HMatt]

It's worth a shot... If you had said the resevior was a little low or there was a leak I was going to say you blew an internal seal so when your pressures would get high, it would let go and a little ATF would drain from the diff into the transfercase. You can check it by draining a little oil from it and seeing if it's pink. The problem with that is if you use redline fluid, it'll be pink anyway...

The thing is, if you replaced the pump and controller, the only thing that's left is wiring, sensors, hoses, and the transfer case itself.

[EvoIX007]

Just stopped by KTM, just wait till you find out the cause....:eagerness:

[HMatt]

Just stopped by KTM, just wait till you find out the cause....:eagerness:

I'm guessing it was something retarded like a sensor was unplugged? haha!

[Mister]

< ---- Also curious what it was....

[FUEL]

All the tracking you killed it... just disconnect it and drive it with no ACD ... you don't need that shit anyways.

[HMatt]

^Yep, dead as a fucking doornail. HAHA!

On a serious note, OP, I don't think you killed it... I mean hell, the Sierra Sierra evo still uses a stock ACD in it. Granted they use an expensive-ass Motec controller for it.

[flyingscot too]

All the tracking you killed it... just disconnect it and drive it with no ACD ... you don't need that shit anyways.that doesnt work as your abs works with the acd,it controls yaw angle under braking,in other words kills the fishtailing,your car with no acd will have no abs and youll get constant lockup with your normal pedal pressure,ask me how i know?
John ,i have a spare acd computer if you want to try that but im thinking you guys have already tried that
You checked the G sensors right? They are located under the center console between the shifter and hand brake

[Johns_EVOIXSE]

that doesnt work as your abs works with the acd,it controls yaw angle under braking,in other words kills the fishtailing,your car with no acd will have no abs and youll get constant lockup with your normal pedal pressure,ask me how i know?
John ,i have a spare acd computer if you want to try that but im thinking you guys have already tried that
You checked the G sensors right? They are located under the center console between the shifter and hand brake

We tried the ECU thinking it fried. Your 13k mile unit now resides in my car however

It was just a stupid fuse that blew coming off the positive battery terminal. -_____-

Let me tell you driving with open diff sucks. Car drove like a Toyota Camera last month at Big Willow. When the ACD goes into stand by mode you basically have open diffs and the car is more fwd than awd. I was still able to run a 1:31.7 and get 2nd place at Redine Time Attack without it. But I can guarantee you I would of been in the high 20's with ACD.

Braking stability is vastly compromised. ACD locks the diffs under hard braking.

Intitial turn in sucks, you know that feeling you get when you turn the wheel, and you can feel the grip with the turn of the wheel. Gone.

Mid corner was actually not that bad. Probably due to my decent suspension.

Corner exit, forget about it. Under under under steer!


Overall, it's like driving a Toyota Camry. Car is very floaty. You know when your on the freeway and you barely turn the wheel and your over three lanes, and it's a floaty kind of feel? Yeah. Open diff sucks!

All the top TA cars went back to ACD. Cyber tried it for a few years without ACD and went strictly mechanical, only to go back to ACD.
Sierra Sierra, ACD. Tilton Interior's ACD. You can't beat having a computer controlled LSD.

Here is what it's like driving without ACD. You can see how floaty the car is cresting over T6 at big based on my inputs. Sure its a hill, but it's not usually like that. Usually that is one solid saw of the wheel. Instead its two saws and me compromising for lack of grip... I also had to modify my driving to not take corners exits as aggressively due to the amount of understeer the car now had. T9 was also sketch (more than normal) http://www.youtube.com/watch?v=6mchgNPvgmY

Luckily I was able to adapt quickly though. Car still sucked.

[ebevo]

wow fuse on the positive battery terminal caused all the fuss damn

interesting line you took at the top of the omega turn (turn 4, 1:06-10 mark)

[FUEL]

So of you disconnect the ACD completely ...wouldn't the Diffs work as mechanical Diffs? Sorta like an VIII RS? As for ABS ...RS ...no ABS either ?

[HMatt]

^Nope. The ACD pump pressurizes the center lsd, causing it to lock up. If the pump is in standby meaning it is off, then it doesn't pressurize anything. No pressure = no lock-up.

[Johns_EVOIXSE]

Kevin (Flyingscot Too) , thanks for the pump btw! Still an upgrade over my old pump from a mileage stand point.

[flyingscot too]

Kevin (Flyingscot Too) , thanks for the pump btw! Still an upgrade over my old pump from a mileage stand point.no problem,keep your other as a spare

[HMatt]

^Werd, even the rebuild kits are not cheap, then you still have to install it!

[GokuSSJ4]

Very interesting thread. Thank you guys for the valuable info. It's good to hear how wonderful the ACD can be. ;)

[Johns_EVOIXSE]

wow fuse on the positive battery terminal caused all the fuss damn

interesting line you took at the top of the omega turn (turn 4, 1:06-10 mark)

Yeah, it's the Jack Olsen line.

I take it like that to set me up for T5 which is the most important turn on the course. If you can't get out of five quick enough it slows you down for back straight going into T8.

[sipyohaterade]

A good working acd pump should be making at LEAST 10 bar and 72 psi sounds really low to be honest. Just pointing out you could possibly have a bad oring on one side of your pressure plate.

[Johns_EVOIXSE]

A good working acd pump should be making at LEAST 10 bar and 72 psi sounds really low to be honest. Just pointing out you could possibly have a bad oring on one side of your pressure plate.

Thanks for the heads up. I'll try and log it with some hard braking and full throttle blasts and see how the data reads.

[Orange Max]

I had issues with my ACD system. It turned out that the pump was bad. I choose to replace it with a new OEM pump. Not cheap by the way.
MAX:mitsu_logo: