BluesunsXIV

Im making a thread because to the uninformed this problem may baffle you. To those that are in the know, please understand im only writing this for those that dont know what im talking about and are new to the tuner scene like myself----

I had an issue where at a high rpm my car would jerk violently and it would feel like it wasnt flowing properly. It would eventually lead to an ASC off and service required light in yellow with and (!) in the center

If you have a boost controller the problem may be that your "overboosting" or if you do/dont have a boost controller you may have a leak somewhere. The car will compensate for this problem by cutting off your fuel so that you do not blow up your motor. Somehow my MBC was turned to a higher psi then it was originally set for and this caused the overboost. By turning it down the car ran perfect again. What you need to do is lower the boost and continually adjust it until you get to a boost level suitable for performance but one that will not cause fuel cut off. Remember to unplug your ground to your battery so that the car will not register the fuel cut off once you drive it again or else it may turn on again. Give it 30 seconds b4 you plug the ground back on and start driving.

Incidentally the ASC off and service required light is only indirectly related to the problem. If something is wrong with your power levels, or you run over a bump, have misaligned spacers, anything that is wrong that shouldnt be... the evo Xs sensitive S-AWC system will turn the system off so that you do not ruin your transmission in the process. In this case here, the violent jerking caused the sensitive awc system to be disabled. Dont worry, you can turn the car off and back on and it will go back to normal. If this is not the case you may have another problem that is also disabling your system and you should visit your local stealership. lol

I really do hope this may help some poor schmuck out there like me someday. Happy Riding!

SpeedI2acerX

iTrader: (2)

i remember a week after having the car, stock and untune/no flashed, i was at a light and the car jerked and stall. pissed me off being that its a new car. of course it never happened again.

tipoytm

As I keep reading similar problems as posted by the OP, there's a lot of talk that the X doesn't take well to MBCs. IMO, it's safer & better to have the car professionally tuned for max boost instead via the ECU and replacing the stock pill, etc.

Hiboost

iTrader: (9)

The yellow warning (!) with skid marks is likely you just exceeding the torque limiters map. The boost cut at higher boost could be boost limits tables, turning the boost down lower so that doesn't trigger was a wise move. I'm not sure what boost levels your car was originally tuned for but if you change it with an MBC then typically you will build more boost with the lower TPS inputs then the ECU is expecting with it's built in boost control setup. You should be able to adjust the airflow and torque limits tables to accomodate a reasonable amount of boost, which usually ends up being 25-26 psi at peak torque on the stock turbo and tapers down to 20psi by redline. The boost limits tables should be ~10% higher load than you typically see so that the safety feature is still functional. I would contact your tuner and get it touched up if you intend on running boost higher than it was originally tuned for, but it sounds like you already turned it down so you should be fine.

BluesunsXIV

My tune and MBC was set for about 25-26 psi, but for some reason the MBC went higher then 26 psi and it wasnt just for the initial spike. I would NEVER intentionally up the boost beyond safety and especially NOT without a tune. Idk how it got that way im just glad i was able to find this out b4 i blew the motor. Perhaps the spring settled, maybe the weather had some affect (I did have the car tuned in February and its def warmer now lol) idk much about MBC's, do they have a tendency to fail or premature?

SCREAM8

iTrader: (5)

which type of mbc? hallman? you sure it wasnt leaking?

buddy was having similar issues with his evo x and a leaking turboxs mbc.

BluesunsXIV

it was a hallman, cant be sure it wasnt leaking, any way i can check this at an idle?

hoongss

iTrader: (2)

Where do I check for leak? I have that ! After running high rpm. I don't have MBC This happens after I got a turboback.
I got the HKS BOV before the turboback.

ArtofRalli

I had the exact symptoms this morning. All the same lights came on ect. I have no mods what so ever, stock map and i was not touching the throttle at all when this problem occured. I was cruising at 80km on the hwy and the car was on but had no power at all! i pulled over to the side of the hwy turned of the car and back on. the car was fine with the engine light still on.

Clearly i could not be over boosting, what could be the problem? im thinking a leak

dek0026

at bumping this thread. The OP sold his X and bought a used TL-S.

Aside from the many issues he had with his car, he later found out he was driving around with the fuel pressure regulator hose popped off.

kronik5383

iTrader: (1)

i am having a very similar problem to this, feels a lot like fuel problem.....will check the regulator line