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Hesitation/vibration/jerking/kicking/overboost, high rpm, ASC off & Service Required

12K views 13 replies 11 participants last post by  hollywood_X 
#1 · (Edited)
Hesitation/vibration/jerking/kicking/overboost, high rpm, ASC off & Service Required

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 overboost registers higher then the torque limiters map allows, causing the 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! :rock:
 
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#2 ·
So I've tried searching my issue, and found this to be the closest thing to it....Alright, so I've never turned ASC off until today. I'm at a stop light on an incline. I decide to to turn ASC off, just one click, not all the way off. I rev to about 3k rpm, and I go into limp mode I think. I've never really had this happen before, so not sure if it was in fact limp mode. But power was immediately cut and a warning light with a squigly line (for lack of a better word) showed up. Also, a couple of days ago, the "Service engine soon" light came on, but yesterday and today, it was off. Of course, after I pulled over, the "service engine soon" light came on again. And the revs were surging from idle to about 1500-2000 rpm when I pulled over. I turned the car off, waited a few seconds, turned it on again. The revs went straight into that surge again. I also couldn't turn ASC back on at this point. I turned the car off again. Waited, then on again, and it was back to normal, with just the "service engine soon" light on again.....

So, mods on the car are in the sig... Any ideas wtf happened to me? Again, it was the first time I pressed the ASC button.
 
#3 ·
Wow Interesting.

Sean



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! :rock:
 
#5 ·
Cool, thx. The car is running normal now. So I'm correlating the issue with me pushing the ASC button so far, as there were no other factors of things that I don't normally do. And "service engine soon" light is off as well..... weird.
 
#6 ·
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
The now notorious faulty fuel pump relay also causes the hard hesitations/jerky powerband which will pop the ASC light. I had the same type of issue. For the hell of it I tried swapping my fuel pump relay for the horn relay. All of a sudden the car pulls ultra smooth all the way to redline and now the horn is acting up, which pretty much confirms that it was, in fact, the relay causing the issue.

It's a quick and easy fix, and one that everyone should try out if they start having any problems. Running extra lean could have far worse consequences than overboosting by a couple psi.
 
#7 · (Edited)
Well I guess its "nice" to see I am not the only one seeing the ASC off light turn on and the ! sign come up randomly. I guess an overboost issue is possible, seeing as how I am running 31 psi.

However I am dyno tuned and none of this was experienced on the dyno. Fuel control was there completely. I am thinking that my problem is coming from the stock clutch slipping for me.

Mine seems to happen only at lower loads. Like if i floor it when its 2000rpms, the boost builds but the car doesn't really move. The easiest way for me to get this light is 5th gear, 2000rpms and full throttle. Mine isn't a limp mode though and the code is not in the ecu, my tuner checked it. I am going to get it checked out at the stealership soon and I guess if I find anything out I will let you guys know. I am pretty sure mine is not the fuel pump relay as if it was I would've seen it on the dyno and/or my engine would be gone with the timing I am running with E-85,lol.

Anyone have any ideas what this could be from in my case?

Here is my car after it happened stopped in my driveway.
 
#8 ·
Well I guess its "nice" to see I am not the only one seeing the ASC off light turn on and the ! sign come up randomly. I guess an overboost issue is possible, seeing as how I am running 31 psi.

However I am dyno tuned and none of this was experienced on the dyno. Fuel control was there completely. I am thinking that my problem is coming from the stock clutch slipping for me.

Mine seems to happen only at lower loads. Like if i floor it when its 2000rpms, the boost builds but the car doesn't really move. The easiest way for me to get this light is 5th gear, 2000rpms and full throttle. Mine isn't a limp mode though and the code is not in the ecu, my tuner checked it. I am going to get it checked out at the stealership soon and I guess if I find anything out I will let you guys know. I am pretty sure mine is not the fuel pump relay as if it was I would've seen it on the dyno and/or my engine would be gone with the timing I am running with E-85,lol.

Anyone have any ideas what this could be from in my case?

Here is my car after it happened stopped in my driveway.
Check the fluid reservoir in the trunk, it's on the pass side behind a small cover.

Also, load on the dyno does not always correlate to load on the road, you will often carry more boost farther out in the rev range on the road than on the dyno. I have never had one code on the dyno, it's always on the test drive afterwards and often has to do with how the owner drives the car.

For example why the heck would you go wot in 5th gear at 2,000 rpm unless you were trying to induce a code? ANyway, you need to get with you tuner so they can either sort out the check tables or disable the check timers.
 
#9 ·
I was getting this same problem ASC light and car would go into Limp Mode. Took it back to my tuner and he fixed it....It would happen when I was in low RPM's and then punch it, didn't happen all the time, but it sure did suck when it happened on the highway and I had to pull off. Anyway take it to your tuner and they should be able to fix it.
 
#10 ·
Hi

I had a similar problem (inlcuding the ASC error code)- took it into the dealer only to find out two days later that one of the vacuum(the tiny one going to the top of the engine) pipes had come loose. The clamp had somehow been dislodged.

Once fixed this back in place the problem vanished.

Thanks
 
#14 ·
This happens any time you go over any of your limits tables and usally followed by and engine code of some sort (Not always)

You car has limits tables for Load, torque, and air flow. (Plus a few others)
Most of the time you won't see loads over 275 or so on a stock turbo but everyonce in awhile you may get the boost just right to get'r done. If its over these limits for more than 2000 milli seconds it will dump the WGDC on the (Fine/Reactive) solenoid to zero dropping boost and switching you to limp mode mapping.
 
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