Beware of rumble strips on the Interstate-read why
 

This may belong in tuning and diagnostics, but this experience applies to anyone on this forum, tuned or not tuned.

I have a 2011 SS LS3. You can see my minor mods in my signature.

I was on a road trip this past Wednesday through Friday and had driven from SC to just outside on Knoxville. Some construction and lane shifts brought a lengthy stretch of those impressed into the asphalt rumble strips under my left front and back tires.

I had been cruising for hours in 6th gear around 65-75 MPH at this point. The rumble strip contact happened for a good 10-15 seconds, not just a little burp of contact.

As soon, as that was over my car got extremely sluggish and would not maintain speed in 6th gear. I'm talking having to put the pedal to the floor almost to maintain speed.

My first thought was that I had melted/shook down a catalytic converter. The experience simply felt like a bad cat, but there is no CEL (but my rear O2's are turned off so?)

I continued on to the motel I had booked for the night. Of course during this time I'm considering my options like going to the dealer in the morning to check the car, or getting someone to gut my Kooks hi-flow cats. Mind spinning along thinking about is it this or that.

I was in Knoxville for a funeral, so I made several short trips here and there over the next day and the car seemed to be getting better each time I drove it, but still very sluggish.

It got better enough that I opted to push on to my next stop in Atlanta. During that several hour run, it dawned on me that it could be the knock sensor that caused all this.

To cut to the chase. That is what it was. The car got grossly detuned far beyond anything we may attribute to octane tables and such. I presume with the extended period of false knock it switched octane tables and also changed anything it could to make the knock go away

So, I got home late Friday, but had committed to go to the Charlotte AutoFair Saturday morning. On Saturday I went and filled up near the interstate before heading out, thru my SCT tuner on and re-flashed my Jannetty tune.

I wiggled the rear end and traction controlled all the way up the entrance ramp to the Interstate, and now it would run in 6th gear with just the slightest amount of pedal. Gone was the incessant drone of the exhaust because of the car being under load to maintain speed.

So, that proved the tune being instantaneously trashed because of the rumble strip and false knock.

Now the point of my post here in this section is that I do not think my car being tuned had the slightest thing to do with this. I suspect it could happen to any stock V8 Camaro. Also, this seemed to be a permanent change to the tune.

So, similar to the infamous fuse pull situation, you could be driving around in a car that needs the ECU flashed back to factory default and not even know it.

I'm sure this thread will propagate a bunch of BS replies and such. But when your wife sitting in the passenger seat for the past three days says holy sh*t after flashing the tune, you know this was not just some minor power problem.
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If this was an issue, you'd think we would have seen it before now.

Would be interesting to test this theory with a live feed hooked up to the ECM.

Probably... brace yourself! ;)

Would chalk this up as a unique 1 time error or something wrong with particularly your Camaro. If this was a true cause we would have all encountered it by now.

I'd buy that... rhythmic vibration of different frequencies can do all kinds of strange things to a car. Certain frequencies of rumble strip- type roadway can essentially nullify the braking capabilities of vehicles equipped with ABS, sort of "fooling" the braking system into falsely predicting impending wheel lockup, thus releasing the brakes.

Interesting possible cause. Sounds feasible. I drive over some for a much shorter peroid of time moving into a turn lane on my commute and nothing yet, but these are very short rolls over those rumble strips, cutouts in the pavement.

Based on other recent threads, I have expected this to be an airbag deployment issue... which would have sucked as well.

Yes, that is why I posted for discussion. I cannot believe I have not seen this issue posted. I've been here quite a while.

Maybe is had to do with an exact speed and exact set of parameters to reproduce the frequency the knock sensors look for...but it unquestionably happened.

I also think that this is not necessarily unique to the OP's vehicle, but the circumstance was unique: Most of time, when wheels hit the rumble strip, the driver gets out of that, steers away from that jarring, irritating state. The OP stated that it was for 10- 15 seconds, for whatever reason, which is a damn long time. And, rumble strips are of different frequency, and at different speeds, they will do different things: Point being, it is very likely that he just happened to hit the "sweet spot" of frequency, the one that detuned things.

Agree 100%

I suspect it put the car in REP or Reduced engine power due to the vibration setting a fault on the throttle position sensor.

Usually shutting the car down and restarting will reset it unless the fault remains.

The vibrations could haven knocked a connection lose.

I would inspect all ground connections and all harness connections.

Ted.

I can relate. I drove on a road that was so rough the other day that now my radio only plays songs from Guns and Roses.


(Sorry couldn't resist)!

Thanks all

I say have some go back to the same location with a different car and see if it does it to there's that would be a myth busters show!

Crazy post. I can see the knock affectign it but it wont "detune" anything. I can see it going to reduced power mode to protect the engine, but you shouldnt have had to reflash the tune. Just disconnect the battery or do the fuse pull