Ahoy,

Just got an '08 base/stick with 8,600 miles on it for $3,000 under book. Good times! Love the car, but noticed something odd last night that I've never experienced while driving any other car.

We had some snow/rain mix that turned the road pretty slick, so I skidded a few times. That's pretty common in the northeast (heh), but when the car slides I hear a grinding sound from under the car, and I feel a strong vibration in the break pedal. The pedal almost seems to ... bounce under my foot.

It only happens when the car is in a slide. Is this an ABS thing? Is it normal?

Been trolling here since I decided to buy the car. Looks like a nice place.

regards

 

Yeah thats the ABS!

 

Yes, that's normal for ABS. What you feel is the ABS pulsing the brakes at a very high rate. The sound is the valving in your brake master cylinder working hard at regulating the high pressure in your brake system. The vibration is the corresponding pulsing of pressure in the hydraulic fluid. You feel it in the pedal through the shaft that connects the pedal to the master cylinder. You feel it in the vehicle through the rotors/wheelbearings/wheel mount.

 

^What he said.

 

I believe its the EBD, 'electronic brake distribution' system. Though allied with ABS it is more likely Honda's electronic stability system.
Last weekend I had the oportunity to drive VIR in the cold with only snow tires. Even over the continuous howling of the tires the racheting was noticeable in tight and medium turns where the Fit drifted across the many apex. It is normal but it is definitely out of character.

 

^^^ Its not the EBD system, it is the ABS and every single car on the road with ABS does the same thing.

 

The racheting on mine occurs under full power with no brakes as I'm sliding across the apex of a turn sometimes under opposite lock. No brakes. Since my brakes aren't applying pressure does ABS ene activate? If it did, it wouldn't do anything.
Like I said, it appears to part of the same program as ABS but not necessarily the same as its trying to hold the back end in line following the front wheels path rather than shifting braking.
Both ABS and stability control work by releasing and applying brake fluid pressure to the brake reservoir very rapidly to keep the wheel rotating. A rotating wheel has directional control while a stopped wheel has no control hence sliding in an uncontrolled direction.
In my case both wheels are rotating pretty equally without brakes so I believe the system may be trying to react to the vehicle wheel path compared to steering input. I haven't seen video from outside so it could be the inside wheel lifting a'la' VW's classis hind leg lifted pose.
That would be worth a photo.
If you're on ice with both wheels and they both have little or no traction I'm not sure what ABS would do or even if the ABS would activate. ABS reacts by comparing each side wheel rotation with the opposite side. If they are the same I'm not certain ABS will activate, regardless of brakes applied. And what engages EBD? Something relating to steering angle and wheel angle? Interesting.
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We tracked down the culprit. Apparently it is the EBD. ABS works side to side to equalize braking. EBD works front to rear to make up for changes in weight distribution. Put a heavy load in the rear and EBD lets the rear brake pressure build highrer before cutting off with the proportioning valve. In other words an automatic rapidly adjusting proportioning valve.
So in our case as we cranked thru those turns the rear end chaged weight enough to trigger that proportioning valve without seeing a side-to-side wheel slippage. That occurs regardless of braking as the EBD tries to adjust the brake pressure maximum.
Why is this important? The EBD measues the loasd on the rear end of the car and changes you moake to the suspension can be a factor. I suspect it would be most a problem for really substantially lowered Fits pretty much running on the bump stops. And since I have Airlifts with 80 psi preload that may be why I get the racheting.

 

The Fit's my 1'st ABS car and I tried them out the 1'st time it rained. It was a little freaky to feel the brake pedal vibrate like that. The car stopped perfectly straight, what a cool invention!

 

Ah, thanks. The replies have been quite instructive. It's going to take some ... getting used to. :-)

 

I honestly thought I'd lost a front wheel bearing and maybe a caliper the first time my ABS came on. Something that I don't think the manual discusses.

 

You're right - the manual doesn't address what ABS engagement feels & sounds like. It also doesn't address the ratcheting sound of the e-brake when it's engaged, or what the car feels like when you hit the fuel cut past redline . . .


Like others have stated, the pedal vibration & accompanying sound is a totally normal phenomenon. It's how ABS let's you know when you're braking more aggressively than the conditions will allow, and it's accompanied almost every ABS system since it began seeing implementation in cars in the 1970's.

 

According to Edmunds, ESC and traction control are not available on the 08 Fit which is what the OP is driving. See link here:

Comparison Test: 2008 Honda Fit vs. 2008 Toyota Prius

 

Agreed that Fit doesn't have ESC (thank goodness) but it is the EBD.

ABS works side to side to make up for one side with traction and not the other based on comparing wheel rotation; EBD works front to rear to make up for changes in weight distribution. The more weight in the rear, the higher pressure permitted by the automated proportioning valve.
honda's manual drawings should have labelled the upper curve as a curve that rises as the rear weight increases. The curve is the proportioning valve output; the steps are the result of ABS 'racheting' the curve.
See prior edit for more detail. Having tended a Tilton oftenI like EBD.

 

If Honda's EBD is just working off the proportioning valve, it isn't going to cause vibrations experienced when the ABS valving kicks in. Otherwise, it's really an integral upgrade to ABS, not something separate.

 

ive tried comparing braking with the ABS engaging, and braking wit a softer touch, like right before the ABS would engage. Turns out, ABS is actually worse than a soft brake. but then again, ABS is still better than slamming and locking your brakes. i think, instead ABS, we should have a maximum braking, meaning, the car won't allow the wheels to lock up AT ALL. the ABS still locks up the tires, but intermitmently (or how ever you spell it). and by maximum braking, i mean the car wont allow the wheels to lock up no matter how hard you push on the brake, buh rather put as much brake as possible before the wheels would even lock up.

in final saying: ABS, not that big of an invention... old fasion soft braking works best.

I also noticed, and learned in drivers ed, that when your spinning or over-steering, you hit the nuertrel and it kinda corrects itself back onto track, or at least where the steering wheel is directing it. just talkin from expierence. and trust me, ive drove in a shit load of snow. Heres the even more stupid part, with stock tires too broke to upgrade lol

 

Sorry, but I have to disagree.
As any engineer having performed braking tests on a slick surface (try Mobil 1) will assure you when the traction of a tire falls less than the ability to adhere to the road there might as well not be a steering wheel. It will flop around without reason or anything beyond imperfections in the tires path. No soft touch will correct that.
ABS is a great invention. I say that even though I drove GM marketing crazy at a truck unveiling at CMS by always stopping quicker without using ABS on their little stopping test with only the left side free of soap suds. A good touch is good but ultimately but when the chips are down ABS counts more than experience. No matter how experienced. I got used to ABS braking in racing where skill was immaterial, performance was paramount. And ABS ALWAYS gets to the limit, humans don't.

ABS compares rotation of left and right side tires and matches the one that rotates according to the faster rotation presuming its the one with traction.
EBD controls the proportioning valve output based on the weight(height) of the rear wheels. Because the braking effort is dependent on the weight on the wheel, the porportioning valve needs to shut off more pressure to the rear brakes to prevent it from locking pu and losing directional control (like using only rear brakes on a bicycle or m/c for a really fast stop. few of us did it again). EBD raises the maximum pressureallowed to the rear brake as weight increases; that is a definite assistance in braking.
ABS works after EBD is applied.

 

Yep, you got it.
The proportioning valve programming likely ratchets just as the ABS does, and both together may be one heck of a racket.

 

Ok, OP is touching the brake pedal so the noise and feel has to bee from the ABS system.

But how would VSA (Vehicle Stablity System - that system is on the GD1 MT and GE over here in Europe atleast) react when skidding? Or is VSA only reacting when trying to accelerate and one wheel is spinning? Does VSA do anytning to the steering at all?
Since I have a GD1 with CVT the VSA is not an option on that car.

While I was testdriving a GE a few weeks back I tried out the VSA system and it appears to react on the brakes, it felt like it anyway. But no noise was heard other than the engine rpm going down when the yellow triangle with an ! inside started to flash on the dashboard. And I could only get it to activate when accelerating on slippery surfaces where probably one wheel was spinning.

 

Just a note for those new to anti-lock brakes. When the ABS activates and you feel the pedal pulsing, don't panic and let up on the pedal, just keep pushing for maximum braking. If you're new to ABS I recommend "test braking" a few times to get used to it. After getting used to it, I won't buy a car without it. My wife was looking at Toyota Matrixs and could not find one with ABS (don't know why ABS was uncommon on 08 Matrixs, but it was). She bought a Mazda 3 instead for that reason alone.

 

Vehicle Stability Systems I have data on work by comparingvehicle attitude and 'adjusts' by addressing pressures to brakes and adjusting throttle signals to correct what is programmed to be a not desireable position. It is very conservative to 'take care' of inexperienced drivers. Most competition drivers don't like VSC because it reacts much sooner than the comp driver as they usually like to 'hang-it-out' a bit more than the programed thresholds are set to interfere.
One problem we see here is too many young drivers come in thinking they can drive as wild as they want and VSS will 'drive it right' for them like some video game They can then text without woory.
We tell tell to try a competent racegame like F12002 or 2006 and text while they are lapping. So far no one has made without crashing. Some of them got pretty sober looks. Maybe the county mounties and highway patrollers ought to try that as a teaching aid. Step up and try the driving while texting or cell phoning ... (set the vehicle speed at least at a competitive level) and watch the fun.