two SCARY sudden acceleration incidents 92 Audi 100S

Page 1 of 2  
Happened yesterday. Below is text of two messages I sent to NHTSA on their complaint form. Notified AUDI US also, but no reply . I always thought these claims were BS and from old drivers who accidentally
depressed the accelerator pedal when they thought they were pressing the brake. It is scary, it is real and it needs to be looked into by Audi. I skydive and I have had two main chute malfunctions that required cutaways. I have experience in handling emergencies and not panicking. I was NOT pressing on the gas pedal. I didnt want to shut off the engine with the key until I was stopped as I feared losing steering.
I looked on the NHSTA website and there have been a couple of other complaints besides mine that were nearly identical. One guy assumed like I did that it was a cruise control issue, but it isn't. He is probably still driving thinking the problem has been fixed. The second incident happened with the cruise fuse pulled.
Anyone have any ideas? The only clue was brake pedal effort seemed to increase right before it happened, as if vacuum boost had been lost or decreased. All ideas appreciated.
first incident:
RUNAWAY THROTTLE. UNCOMMANDED ENGAGEMENT OF CRUISE CONTROL? WOULD NOT RESPOND TO BRAKE OR SHUTTING CRUISE CONTROL OFF ON STEERING COLUMN STALK SWITCH. VERY DANGEROUS!!! ALMOST CAUSED A CRASH, VERY INEFFECTIVE BRAKING WITH ENGINE TRYING TO KEEP CAR GOING AT ABOUT 55 MPH, BUT I MANAGED TO PULL OVER AND SHUT CAR OFF. I PULLED THE CRUISE CONTROL FUSE AND PROBLEM HAS NOT REAPPEARED.
second incident:
DANGEROUS UNCOMMANDED ACCELERATION. I SUBMITTED A COMPLAINT EARLIER TODAY THAT SAID I THOUGHT IT WAS A CRUISE CONTROL PROBLEM BUT IT ISNT. IT HAPPENED AGAIN TODAY WITH THE CC FUSE PULLED!!! IT WAS PRECEDED BY A FUNNY FEELING IN THE BRAKES, LIKE NOT ENOUGH VACUUM BOOST, THEN RADICAL ENGINE ACCELERATION EVEN WITH MY FOOT OFF THE GAS PEDAL. I PUT THE CAR IN NEUTRAL, THE TACH REDLINED AND THEN I SHUT OFF THE IGNITION. STARTED IT AND IT DID IT AGAIN. I AM AN ENGINEER AND NEVER BELIEVED THE STORIES ABOUT AUDIS AND UNINTENDED ACCELERATION... BUT NOW I KNOW IT CAN HAPPEN AND IT IS SUPER DANGEROUS!!!!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
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?
--
later,
dave
(One out of many daves)
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
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?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
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!
--
later,
dave
(One out of many daves)
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

It is most unlikely that they will be terribly interested in examining a 15 year old vehicle...
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

The original poster was talking about sudden, unexpected acceleration. We're not talking about accelerating against locked brakes.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Just a question, but why didn't you shift the car into neutral?
377 wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

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: http://nhthqnwws111.odi.nhtsa.dot.gov/acms/docservlet/Artemis/Public/Complaints%20-%20Correspondence/1996/Correspondence/Incoming/CL-503613-YN.PDF
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
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)

http://nhthqnwws111.odi.nhtsa.dot.gov/acms/docservlet/Artemis/Public/Complaints%20-%20Correspondence/1996/Correspondence/Incoming/CL-503613-YN.PDF
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
The cruise control system in your vehicle is completely separate from any sources of engine vacuum and is controlled by a separate control unit. The entire system is completely isolated from any other and only uses inputs from other systems such as speed, etc.
All quite irrelevant since you have effectively removed the cruise control system from the scenario by completely disabling it.
Leaving very little to possibly suspect. There is no other mechanical control of throttle.
The components of the throttle body system are: the throttle body, a potentiometer that senses throttle position and movement, the idle stabilizer valve which meters air in order to keep a steady idle, an EGR valve for emmissions control, and a temperature sensor. None of the latter items mechanically manipulates the throttle body.
Without mechanical actuation of the throttle body and in order to achieve the power output you describe, the engine will require accurately metered air and fuel. I have no idea if the ISV or EGR, either together or separately, could introduce a volume of air equivalent to a fully opened throttle plate.
Nevertheless, air and fuel and accurate management of both must be present to achieve anything remotely resembling full engine power.
Do you recall noticing the position of the throttle pedal? Was it on the floor? What was the nature of your most recent throttle application?
The engine vacuum system on this model seems rather tortuous. There is a "damper", the function of which I have no idea, a solenoid valve of some sort, a "vacuum unit for intake manifold" which I believe is merely an tap into engine vacuum, and some check valves here and there. Then there's an entire subsystem built around a "suction pump" (p/n 078 133 753) which also taps into the intake manifold. By it's name it does not seem to be something that would introduce air into the system, but in your case, something is clearly malfunctioning so who's to say.
Finally, have you run the diagnostic output from the ECU to see if there are any error codes stored? This may give you some add'l insight.
I hope some of the above helps get closer to the cause. Give the age of the vehicle, I'm very doubtful Audi or the NHTSA will do anything whatsoever.
Ed
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Ed,
Thanks for your thoughtful reply. Pedal was not on the floor when uncommanded acceleration occurred, I recall tapping it on the first incident thinking it might be hung up and found that it had a normal amount of travel remaining.
On the first incident I had steady throttle, going uphill at 55 mph with cc on but not engaged. On second incident I was in 5 mph bumper to bumper traffic so I wasn't doing any significant throttle excursions. I drive very smoothly and slowly in traffic, not jerky.
No floor mat issues. Accelerator pedal was unobstructed. When I restarted the car in neutral, it went wide open, near redline, limited only by the rev limiter (5500 RPM?). On the next restart idle was normal. There is some link to a vacuum issue, I am pretty sure. Right before the second incident the brakes took extra effort as if vacuum boost was decreased or gone.
Have not run diagnostics. I am sure dealer will. I don't recall any panel lights illuminating.
I hope NHTSA and Audi will take it seriously. An old defective car can kill someone as easily as a new one. Audi seemed paranoid that I was trying to get a legal case going, but I am not at all interested in suing. I just want to keep someone from getting killed.
I was the biggest skeptic in the world about uncommanded acceleration until it happened to me twice in one day. I am lucky that the second incident happened with the cruise control fuse pulled. Otherwise I would have incorrectly assumed that with the fuse pulled it could never happen again and been driving blissfully unaware of the lurking danger.
What puzzles me greatly is how the problem is intermittent.
Mark
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
There was a recall of some 92 100 cars to replace a rotary vacuum pump with premature vane wear with some sort of "vacuum unit", perhaps a tap into the vacuum line with a check valve.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Jun 19, 10:30 am, snipped-for-privacy@gmail.com wrote:

First, I found a possible culprit. The neck on a 3 port plastic valve in the vacuum line that runs on the top of the engine, driver side, and feeds the brake booster was broken on the suction side (the side that leads to the intake). The hose was sucked against the broken part of valve when the engine was running so the vacuum loss was not complete. What was disturbing is that the neck, which should have remained firmly fit in the hose end, was missing and nowhere to be found. Could this have disintegrated into small particles and have been sucked into the throttle body? Could a foreign object here cause increasing (not just stuck) fuel delivery? I don't know, but it is a clue.
Audi America's response was waaaay beyond disappointing. They sent me to a dealer who wrote up a $2000 repair estimate including $750 for a new throttle pedal assembly, new floor mats, hundreds for unspecified "decarboning" and did nothing to find the root cause. Although this was CLEARLY an uncommanded acceleration issue, NOT A STUCK throttle, they treated it as a stuck throttle issue and would not even open up the cover to the throttle body on their dime. I called Audi America HQ and spoke to Michael Harris. I told him I was not making a legal case, not seeking money, just trying to prevent fatalities. I told him that Audi could not possibly find the root cause if they replaced every bad part before finding what caused the problem. He was polite but wouldn't change anything. Oh well, I tried. Who knows how many other 92 100S owners have had this happen. Three have reported identical incidents to NSHTA, but I will bet there have been others who didn't even know how to file a report. If this happens to an old or non alert driver it cold result in multiple fatalities. I am going to replace the broken valve, replace the old vacuum hoses in that same line and see what happens. I am almost sure that the valve lies at the heart of the matter since it causes partial/intermittent loss of brake boost and that immediately preceded the acceleration. The plastic was very brittle and the neck particles probably did get get sucked towards the intake/throttle body, perhaps even entered it. I don't know enough about the Audi fuel injection system to know if a foreign object in this area could cause an increase in fuel delivery. Does anyone else know?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

sell now,
clearly stating for a 1992 motor it still has wonderful acceleration............
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Fri, 15 Jun 2007 10:56:43 +0100, "Yes Baby"

1. Get a job and stop trying to make money off of Audi.
2. If you must drive, learn where the brake pedal is.
3. 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)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

15 years...............were the brakes working.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.