ntguru

Hi all, I posted this once before but got no response and now I'm worse off so posting again. My dealer has had my car for almost a week total on this issue now, and has seen the problem (after I drove with a tech), but has no idea where to look. Here're the basic facts:

-the car was in a fairly serious frontal collision, so most everything up front was replaced or at least taken out (including motor) during repairs
-car accelerates normally (hard) until 115mph, then it feels like something cuts out, car will accelerate more from there, but VERY slowly (much slower than if something like supercharger were disengaged) No display errors and no errors in the computer (checked by dealer)
-after the 115 limit above, for anywhere from 30 seconds to 15 minutes or so, the car, even at lower speeds, will have no power. If I turn off the car and restart or spontaneously between 30 seconds and 15 minutes of normal driving, normal power returns.
-On ONE ocassion, the car accelerated normally past 115. This time the car had been outside at the dealer overnight on a very cold (close to 32F) night and the run was within 1 minute of starting the car. After several more minutes of normal driving, the wall at 115 appeared and stayed. I'm thinking there is some temperature factor here because on most other runs the car would be parked in my heated garage.

Could this be the intercooler pump? Other thoughts? I'm dying here my dealership is not really on track.

Thanks!

Vomit

Well, I think that you are on the right track in concluding that heat (somewhere) is your problem. I assume that you have checked the engine temp on the multi-display while doing these runs, and that it appears normal? Does the same problem occur if you force the car to stay in, say, 3rd gear at 4500 RPMs for 30 seconds or so, and then shift into 5th and accelerate hard?

Also, I note that your problem is occuring basically in the low part of 4th gear. Any possibility that it is transmission-related?

I would find a way to hook up temperature gauges to the transmission and intercooler.

Vadim @ evosport

IMHO, it is your intercooler pump. It is either damaged from the accident or it intermitently dies on it's own.

Have dealer monitor Intake Air Temperature during a test drive. It should not exceed 200F. DME will shut-off kompressor at 255F.

ntguru

Thanks Vadim and Vomit; I have forwarded your thoughts on to my dealer. I'll keep everyone posted.

Vomit

Does the problem only occur at 115? While you might find this strange, I have been thinking about your problem all day. Seriously, can you run your car hard from 60-100 without problem? If it only occurs at 115 and at no other speed, then I am thinking computer or tranny.

cntlaw

I agree with your logic. If it is temperature dependent, the problem will occur at various occasions.

I am an idiot of mechanics, but I think he should make a big big complain to the dealer. He /insurance company must have paid a fortune for fixing the car. It seems they never did test the car properly before they returned it to the owner.

Not only the transmssion needs to be re-tested/replaced; the driveshaft can also be the 'problem' after such a big crash. Please advise the dealer to inspect it.


cnt

FrankW

i thought u hit the wall at 115mph from your thread title...

Guest0001

thats what I thought.

ntguru

LOL, sorry, I added "...hits acceleration wall at 115 ..." I doubt I would be writing this message if I had hit a wall at 115!

The car has "hit the acceleration wall" a few times at speeds lower than 115. One time I was driving from Columbus to Cleveland and had been cruising at 85-90 for more than an hour. I went to accelerate (not WOT) gently to pass another car and hit the wall at about 95.

Vomit

I agree with CNTLAW's assessment, and would take it a step further. Write a letter to the shop that "fixed" the car, and cc it to the insurance company that paid for it. State in the letter that you are taking the position that your car has not been returned to its pre-accident state, and that you are in the process of hiring an attorney. You actually may be entitled to some damages for the negligent repair. Consult an attorney in your local area. Might be a good case for small claims court, so as not to spend a fortune in legal fees.

cntlaw

Yes. Go for legal first. The repair shop must give you a satisfactory explanation what the root cause of the problem is . You should seriously consider they must have a reassessment of the damage. They probably did not replace the transmission and the driveshaft. And if they did, it could mean a total. If the damage deserves a total, they should give you a new car. Do not take any risks on a repaired supercar while you will still drive it to its limit. You might be just lucky that the engine 'slows down' and not something else.

cnt

cntlaw

Go to the legal , force them to do a reassement of the damage. Should they also replace the transmission and driveshaft ? They did not I suppose as it could mean a total. If the damage deserves a total, they should give you a new car instead of not fixing something and return you the car. It is a supercar that you drive fast to its limit all the time, that requires mechanical perfection. You might be lucky that it only 'slow downs' not something else. Please go back and make a BIG COMPLAIN.

m444

You may want to put the car on a dyno, to document what it does at 115mph. It is easier to test this, and document on a dyno, I think.

ntguru

My dealer replaced IC water pump, car still hits the limit. The tech did mention that he pulled all the numbers from the computer and that he saw some wacky IAT temps -- like -400C and a couple really high ones. I presume there is a sensor that monitors this that could possibly be bad and am waiting to hear back for next steps.

Wiedermann

Mr. ntguru:

Thanks for the update... I've gotten interested in the developments you have on your vehicle.

If your technitian would be able to download all the data at the time you encounter the loss in power, by analizing the data itself, such as the abnormal high temperatures you described, they (repair center/dealership, etc) should be able to take the corrective action on your car).

Wiedermann

GS AMG

Did this ever get fixed and how. I have similar problem with IAT and shutting down.

THX

ntguru

Still a problem at this point. Car's been in the shop for a week now. I had it back for about 10 days and it's been getting worse (happening at lower and lower speed). I went to pass a semi and a minivan on a two lane road and had the "wall" hit at 80mph right in the middle of the semi. Thankfully the AMG brakes well, but still not my idea of fun. I told my dealer that in my mind this has moved from an annoyance (that still needs to be fixed) to a serious safety issue and that I will engage MB USA very shortly.

ntguru

Just got the car back; dealer said they replaced the IAT sensor. Car still hits the wall.

Is it possible (being in a wreck) that my car's stability/slip sensors are messed up and causing the computer to cut throttle? I haven't done extensive testing but acceleration uphills especially and also turning seem to cause more problems and cause the wall to hit at lower speeds.

pokerFACE

I guess you can try it with the ESP off (no throttle-reduction features) if you dare at that speed.

BenzoAMGpower

replace the i/c waterpump again and reset the code... make sure they do it... im pretty sure they didnt replace the pump on ur car if it still does the same thing!!!

saturnstyl

The vehicle may have been repaired as best they could... You will be hard up to find a dealer who will test drive a car at 115 MPH. Its not legal, its not safe. This is just what you will likely hear from the dealer about the car not being repaired properly.

I also tend to think intercooler pump, however when one fails you can usually count on a fault code regarding the intake charge temperature.
Then you can always go back to basics, such as checking fuel pressure when the problem occurs, and getting some good actual value data from the computer when the problem occurs.

doofoo

Any update on this?

-Mike

ntguru

Still not fixed. The problem most definitely happens (from most often & at lowest speed to the least often/highest speed):

1) Uphills....on steep uphills I am lucky to hit 65mph under >50% throttle before the "wall" hits
2) Sweepers ... typically 75ish mph...
3) Normal straight & flat -- around 100-110mph
4) Downhill straights -- 130+mph

Car is going back in next week.

I am retaining an attorney as well for this and matters related to the accident.

ntguru

Anybody have the owner complaint phone number for MBUSA handy? My saga continues with no end in sight so I think I'm going to call them.

cntlaw

The insurance company should give you a new car. Your car was never 'fixed'. It should be claimed as total.

cnt