two SCARY sudden acceleration incidents 92 Audi 100S

You have the 2.8L V6 engine right Mark?

No examination after the incident? hmmm I have seen you post before boeing377 so I do believe you. I just have not personally seen something like this that could not be explained.

I would look at the throttle body, especially the throttle plates and their linkage. I have seen the throttle plates get stuck due to corrosion and lack of lubrication. I have cleaned and lubed many throttle bodies that were operating stiffly/slowly on the AUDIs and VWs.

I have also seen floor mats that jam the accelerator pedal down. 8^o

Had a 1985 Audi 5000S for 20 years and NEVER experienced that problem described here. I also seem to remember that the problem showed up just after starting the engine and AUDI could not replicate this issue. Still they put on a AT Selector-Shift/Brake Switch Interlock on the cars. Was AUDI the first to do this?

V 6 right. I normally would have torn into things trying to find a fault, but I want Audi US techs to look at it undisturbed, that is if Audi US ever responds to my emails. There was no floor mat issue and it wasn't a sticking throttle as you might expect from a dirty throttle plate, it rapidly and radically accelerated. In the second incident I was in 5 mph city traffic and it took off. When I put it in neutral it was up against the rev limiter, close to 5500 rpm with both feet up and off the pedals. In the hands of a panicked old driver this fault can and will kill people. Somehow there may be a clue in the reduced brake boost prior to the uncommanded acceleration incident. Can anyone see a way that reduced or falling brake boost vacuum could cause or be related to this?

Then I wonder where the engine got its air supply from. It must have thought it was on the runway taking off to fly! ;-)

I think on your engine you have a stabilizer valve that allows more air inside of the engine controlled by the ECM. But I am not sure of the controls on your engine except that it should have something to allow air inside without accelerator intervention. Sometimes my '91 Passat will have a very high idle and I need to cycle the ign off and back on. I think I need to replace my ECM since I have checked everything else.

Glad you think on your seat! ;-)

Please post what is found.......I am curious!

It is most unlikely that they will be terribly interested in examining a 15 year old vehicle...

sell now,

clearly stating for a 1992 motor it still has wonderful acceleration............

1. Get a job and stop trying to make money off of Audi.

1. If you must drive, learn where the brake pedal is.

2. Please do not have children.

Dave (who has been driving Audis for 25 years and knows there ain't no sudden acceleration problem. There is not an engine made that can overcome the brakes *IF they are applied)

Try this:

Put your foot on the brake pedal. Have someone that knows where the brake pedal is show you.

In *neutral*, rev the engine to 5000 rpms.

Now, drop the gear shift lever into drive.

I gots me a hundred bucks that says you won't move a foot.

First, there are several ways for an engine to uncontrollably accelerate. Check recall listing web sites. Brake booster blow-out or malfunction Electronic throttle malfunction Cruise control failure Intake gasket blow-out Cracked intake Broken throttle return spring Throttle cable seizes

Second, the brakes in many cars can only hold back a full throttle engine for a few seconds before overheating. Any teen who's thrashed his car can tell you that.

Bull! The brakes that are locked, not generating *any* heat won't overheat. The transmission/torque converter will, but not the brakes.

If you are having an unintended throttle situation while moving, locking up the brakes resolves that issue.

The original poster was talking about sudden, unexpected acceleration. We're not talking about accelerating against locked brakes.

Any situation you can dream up can be overcome by applying the brakes. When this "unintentionall acceleration problem" first surfaced many years ago, it was found to be bogus. One car dealer somewhere on the west coast revved an Audi to 5000 rpms and dropped it into gear. The car didn't move.

Horse puckies. If the disc isn't turning when the pads are applied, there is NO heat. Heat is the product of friction. There is no friction if the wheels are not turning.

The original "problem" many years ago was found to be operator error. There was nothing wrong with any of the cars. The same was true when Cadillac had the "problem".

Dave RS6

Dave,

I have a job. I am an electrical engineer. I never said the brakes wouldnt stop the car, they DID.

I too once held a totally skeptical attitude about sudden accel. I thought it was senile drivers jamming on the gas harder and harder thinking it was the brake pedal. Maybe most of those cases were driver confusion caused, but mine was not.

On the first instance I was driving UPHILL, and the car started to accelerate. I thought it was a runaway cruise control, took my foot off the gas, tapped the brakes, then even shut the cc off, all to no avail. I pulled over, pulled out the cc fuse and thought everything would be OK.

Later that same day in 5 mph traffic, on flat ground, the engine wound up and I had to jam on the brakes to keep from hitting the person in front of me. When I got stopped and put it in neutral it was near redline RPM with BOTH FEET OFF THE PEDALS. I shut it off, restarted it, redline RPM again, right up against the rev limiter. On the next restart it was normal idle.

I am not trying to make one red cent off Audi, just keep someone from getting killed. Believe me, a panicked driver with this problem could easily kill someone.

If you think I dont know cars, I have rebuilt engines myself. I know the difference between a stuck throttle and an accelerating throttle. I am not an Audi expert but I am not an idiot either.

If you think I panicked and jammed on the gas pedal you are wrong. I know how to keep cool. I have twice in my long skydiving career had to deal with main chute failures and I am obviously still alive.

I totally understand your doubts, I once shared them.

Mark

Just a question, but why didn't you shift the car into neutral?

I don't doubt you Mark! I believe you and thank goodness you survived with no loss of life or property. I have seen strange things over the course of years but I always TRY to find a reason why. ;-) I have even seen an oil pump cause a loss of engine compression so that an engine dies.

Now could the ECM have raised the idle to that level? I think it is possible. Does yours have a check light or store codes in the ECM that might blink out the codes or allow you to read with a scanner?

Let us know what you find, or if it happens again!

In hindsight that might have been the best thing to do depending on road conitions. Your first instinct with a runaway throttle is to hit the brakes and that is what I did first. It did stop the car with a lot of effort. I then shifted to neutral, but got redline RPM. On the first incident (uphill on a winding highway) I thought about shifting to neutral while underway on the road but it might have left me stranded on a blind curve since you cant shift back into drive easily when an engine is redlining. I managed to use brakes to slow down and pull over on a turnout.

By the way, Audi US is interested. They are paying to have it inspected at a dealer. They have assured me that there has not been one single case where unintended acceleration was proven. I told them this isn't a "case". I am not suing anyone. It is a safety issue. Look at the NHTSA complaint records online. There are two nearly identical incidents reported for 92 Audi 100S. I think what distinguishes these incidents from most of the ones widely reported many years ago with Audi 5000s is that they (the reported Audi 100 cases including mine) occurred underway, not during parking or startup.

See this handwritten letter, below the stock reply:

That is plain horse pucky. I had a 67 GTO with a stuck throttle (gas pedal to the floor) and I applied the brakes and the car eventially slowed to a safe speed where I could turn off the ignition and coast to the break down lane. AND, those were drum brakes, not nearly as good as any Audi's disc brakes.

You probably didnt read the part where it seemed like brake boost vacuum was lost or reduced before it accelerated. That does increase pedal effort needed. I am NOT claiming that brakes failed to stop the car, they DID stop it. I think the vacuum loss or decrease is somehow related to the uncommanded rapid accel. I AGREE with you that the Audi brakes can and do eventually stop the car even with a redlined motor. All it takes is a strong and continuous application.

In the old Audi 5000 cases that got all the news the vast majority of the cases were as follows (from a news article): "The Audi story is by now, dismally familiar. "Sudden acceleration" accidents occurred when the transmission was shifted out of "park." The driver always insisted he was standing on the brake, but after the crash the brakes always worked perfectly. A disproportionate number of accidents involved drivers new to the vehicle. When an idiotproof shift was installed so that a driver could not shift out of park if his foot was on the accelerator, reports of sudden acceleration plummeted."

My experience and the experience of several other 92 100S owners reported on the NHSTA site was not like this. It was uncommanded sudden acceleration while underway. I always thought the Audi 5000 claims were driver error, but believe me , my experience and the experience of several other owners as reported to NHSTA is really different and far less likely to involve a driver jamming hard on the gas pedal thinking it is the brake pedal. No shifting from park to D.

I was a huge skeptic so I know where you are coming from. This is a real problem and not lawyer driven or driver error. I am not claiming that the brakes failed to stop the car.

That sounds like very good news and good loyalty from Audi. At least they seem concerned with the situation.

Please let us know what happens!

good luck, dave (One out of many daves)