Wtf is wrong with the ABS on the C6
10-26-2007, 11:50 PM
#1
Burning Brakes
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Wtf is wrong with the ABS on the C6
I have had my car for a month now. I have raced it at least once each weekend. As the harder I push the car, I have noticed the ABS seems to be a weak spot on the car. Whenever it engages, the car doesn't seem to slow down at all. The pedal and ABS just seem to pulsate and the car makes no effort what so ever to slow down. I usually have to pump it again to slow the car. I am just curious to see if others are having the same problem. Maybe I am in the ice mode? I don't know, I hate the ABS, TC and AH on the car.
10-27-2007, 01:13 AM
#3
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I have had my car for a month now. I have raced it at least once each weekend. As the harder I push the car, I have noticed the ABS seems to be a weak spot on the car. Whenever it engages, the car doesn't seem to slow down at all. The pedal and ABS just seem to pulsate and the car makes no effort what so ever to slow down. I usually have to pump it again to slow the car. I am just curious to see if others are having the same problem. Maybe I am in the ice mode? I don't know, I hate the ABS, TC and AH on the car.
10-27-2007, 01:25 AM
#4
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What do you mean you have to pump it again? Describe what you are doing.
Bill
Bill
10-27-2007, 06:15 AM
#5
Burning Brakes
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It's not a problem with the rotors. The car stops okay when the ABS isn't on. It's just when the ABS engages, the car just won't freaking slow down and stop. I dont know if the ABS is in ice mode, causing it to just pulse and not do what it is suppose to. It's actually quite annoying.
10-27-2007, 08:30 AM
#6
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You mention you are taking the car to the track frequently, are doing a full flush of the brake fluid BEFORE AND AFTER EACH TRACK EVENT?
When the ABS comes on, and the car is not stopping there is not enough friction between the brake pad and brake fluid. This is a sign of boiled the current brake fluid and glazed or overheated the brake pads.
Ok if the car stops fine when ABS does not come on a few things need to be done:
1. fresh DOT 4 brake fluid - Full brake fluid flush, not just the calipers.
2. New brake pads - stock are fine for street use - but not the track. C5Z06 brake pads are OK for occasional track events
3. clean the surface of the rotors with spry brake cleaner.
Good Luck
When the ABS comes on, and the car is not stopping there is not enough friction between the brake pad and brake fluid. This is a sign of boiled the current brake fluid and glazed or overheated the brake pads.
Ok if the car stops fine when ABS does not come on a few things need to be done:
1. fresh DOT 4 brake fluid - Full brake fluid flush, not just the calipers.
2. New brake pads - stock are fine for street use - but not the track. C5Z06 brake pads are OK for occasional track events
3. clean the surface of the rotors with spry brake cleaner.
Good Luck
Last edited by AU N EGL; 10-27-2007 at 08:32 AM.
10-27-2007, 09:32 AM
#7
Melting Slicks
It sounds like he is definately getting into the ice mode.
Ice mode is energized when the RATE of deceleration of one or more wheels exceeds a preset value. That is, one wheel or more stops so quickly that the computer says "aha!!" the only way this can happen is if the tires are on ice, and therefore I am going to limt deceleration to an appropriate value...
Bill, when this happens, you have to get out of the brakes and essentially reset the computer. A quick lift and then you can brake hard again.
There are a numbr of things that can cause this.
The most common one is if you have a wheel very lightly loaded when you hit the brakes hard. If you have a wheel in the air, it stops so fast that the computer thinks you are on ice.
You may have some anomoly in the braking system that is causing one wheel to "grab". Typically glazing isn't the problem since that keeps the rotors from grabbing, but if three rotors were glazed and one wasn't, the "good" rotor could grab harder and invoke the ice mode.
Finally, maybe it's you.. Try not to "hammer" the brakes so hard at braking onset. Too much braking too fast upsets the car anyway, so brake a bit sooner and smoother. I know it doesn't sound as fast but it really is faster.
Ice mode is energized when the RATE of deceleration of one or more wheels exceeds a preset value. That is, one wheel or more stops so quickly that the computer says "aha!!" the only way this can happen is if the tires are on ice, and therefore I am going to limt deceleration to an appropriate value...
Bill, when this happens, you have to get out of the brakes and essentially reset the computer. A quick lift and then you can brake hard again.
There are a numbr of things that can cause this.
The most common one is if you have a wheel very lightly loaded when you hit the brakes hard. If you have a wheel in the air, it stops so fast that the computer thinks you are on ice.
You may have some anomoly in the braking system that is causing one wheel to "grab". Typically glazing isn't the problem since that keeps the rotors from grabbing, but if three rotors were glazed and one wasn't, the "good" rotor could grab harder and invoke the ice mode.
Finally, maybe it's you.. Try not to "hammer" the brakes so hard at braking onset. Too much braking too fast upsets the car anyway, so brake a bit sooner and smoother. I know it doesn't sound as fast but it really is faster.
Last edited by Solofast; 10-27-2007 at 09:35 AM.
10-27-2007, 09:49 AM
#8
Sure sounds like an electronic issue (ABS related) rather than anything with the pads, rotors, fluid, etc.
My guess is that you are triggering the "ice mode" which in my experience feels just like ABS malfunction....just alot of shuddering and not much stopping. It seems to be triggered at one turn at one of my local tracks. Seems to happen most often when I run in comp mode, and in this particular turn it happens when I jump straight from having the active handling engaged (hard on the gas right hand sweeper) to a quick but firm braking zone. In this case if I am not ultra smooth it will go into this "ice mode" and it feels like the pedal is very high and firm (already pumped up) but I don't get braking worth a crap. In my experience you have to get off the brakes and back on them to get normal braking again.
Maybe something to do with hitting the brakes when the computer is already using them (i.e. active handling is cycling the rear brakes to control wheelspin?) Maybe some turns or situations trick the computer into thinking something wierd is going on and triggers this "ice mode" crap in an attempt to out-think you?
I have a feeling that my overagressiveness (hey, its fun!) in this turn is a likely cause, but I would also say that this "ice mode" crap is definitely not a desired feature and can be downright scary.
BTW, this happed in my 02' Z06 and has happened in my 07' Z51.
My guess is that you are triggering the "ice mode" which in my experience feels just like ABS malfunction....just alot of shuddering and not much stopping. It seems to be triggered at one turn at one of my local tracks. Seems to happen most often when I run in comp mode, and in this particular turn it happens when I jump straight from having the active handling engaged (hard on the gas right hand sweeper) to a quick but firm braking zone. In this case if I am not ultra smooth it will go into this "ice mode" and it feels like the pedal is very high and firm (already pumped up) but I don't get braking worth a crap. In my experience you have to get off the brakes and back on them to get normal braking again.
Maybe something to do with hitting the brakes when the computer is already using them (i.e. active handling is cycling the rear brakes to control wheelspin?) Maybe some turns or situations trick the computer into thinking something wierd is going on and triggers this "ice mode" crap in an attempt to out-think you?
I have a feeling that my overagressiveness (hey, its fun!) in this turn is a likely cause, but I would also say that this "ice mode" crap is definitely not a desired feature and can be downright scary.
BTW, this happed in my 02' Z06 and has happened in my 07' Z51.
10-27-2007, 11:09 AM
#10
Melting Slicks
This problem has been around since the early ABS in the C4. At one memorable Pro Solo in Cincinnati in about 89, EVERY Corvette almost hit a curb at one point because we were slamming on the brakes with the car in the air. The quick fix was to defuse the problem (literally) by replacing the good fuse in the ABS with one that had been blown (by shorting it across the battery terminals) That way we couldn't be accused of disabling it, "the fuse musta just blown?"
Anyway it takes bit of presence of mind to get off the brakes when danger is looming so that you can get back into them and stop the car.
I would have liked it better if the "Ice Mode" was turned off when the car was in competition mode or when the active handling system was disabled. But the lawers know best, they aren't going to disable it even if it makes no sense to have it on the track. Since the computer KNOWS how cold it is outside, you would think that they could disable it if the OAT was above 40 degrees or something like that...
Anyway there isn't much you can do about it, so you gotta live with it.
Anyway it takes bit of presence of mind to get off the brakes when danger is looming so that you can get back into them and stop the car.
I would have liked it better if the "Ice Mode" was turned off when the car was in competition mode or when the active handling system was disabled. But the lawers know best, they aren't going to disable it even if it makes no sense to have it on the track. Since the computer KNOWS how cold it is outside, you would think that they could disable it if the OAT was above 40 degrees or something like that...
Anyway there isn't much you can do about it, so you gotta live with it.
10-27-2007, 11:26 AM
#11
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Really. The only time I experience something like what the OP stated was when I boiled ATE Super Blue fluid and was using Hawk HP Plus brake pads. Just too hard and late braking for an under performance brake or wrong brake pad choice for the 135 mph to 50 mph stops.
Not that attempting to keep up with a GT3 with a very experienced driver had anything to do with it
Not that attempting to keep up with a GT3 with a very experienced driver had anything to do with it
10-27-2007, 12:26 PM
#13
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St. Jude Donor '07
I have had my car for a month now. I have raced it at least once each weekend. As the harder I push the car, I have noticed the ABS seems to be a weak spot on the car. Whenever it engages, the car doesn't seem to slow down at all. The pedal and ABS just seem to pulsate and the car makes no effort what so ever to slow down. I usually have to pump it again to slow the car. I am just curious to see if others are having the same problem. Maybe I am in the ice mode? I don't know, I hate the ABS, TC and AH on the car.
10-27-2007, 12:34 PM
#14
Safety Car
Pull the fuse to the abs and see if the car brakes well. That would isolate the abs system. I would flush the fluid as a start in any case, and check out obivous parts like pads, calipers, rotors etc.
10-27-2007, 01:36 PM
#15
Melting Slicks
I pulled the abs fuse in the passenger door fuse box, the ABS fuse under the hood near the battery, one other I forget where. I was between runs looking at the owners manual and yanking anything that looked like an ABS fuse trying to depower the thing and the abs still kept workin! Finally just gave up and drove the car.... I am a bit surprised GM hasn't gotten sued over the ice mode, because really, in my mind it is dangerous..
10-27-2007, 03:20 PM
#16
Race Director
I have had my car for a month now. I have raced it at least once each weekend. As the harder I push the car, I have noticed the ABS seems to be a weak spot on the car. Whenever it engages, the car doesn't seem to slow down at all. The pedal and ABS just seem to pulsate and the car makes no effort what so ever to slow down. I usually have to pump it again to slow the car. I am just curious to see if others are having the same problem. Maybe I am in the ice mode? I don't know, I hate the ABS, TC and AH on the car.
If so, are your track wheels different sizes from your street wheels?
If your track tires are on something like 18 inch wheels on the back with a smaller diameter tire, your ABS may be a little confused because of a difference in rotational speeds from what it senses with the OE street setup.
As far as AH and TC, you can turn that completely off, so it shouldn't be a bother to you at all.
Bob
Last edited by BEZ06; 10-27-2007 at 03:23 PM.
10-27-2007, 04:19 PM
#18
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Do you have different wheels for street and track?
If so, are your track wheels different sizes from your street wheels?
If your track tires are on something like 18 inch wheels on the back with a smaller diameter tire, your ABS may be a little confused because of a difference in rotational speeds from what it senses with the OE street setup.
As far as AH and TC, you can turn that completely off, so it shouldn't be a bother to you at all.
Bob
If so, are your track wheels different sizes from your street wheels?
If your track tires are on something like 18 inch wheels on the back with a smaller diameter tire, your ABS may be a little confused because of a difference in rotational speeds from what it senses with the OE street setup.
As far as AH and TC, you can turn that completely off, so it shouldn't be a bother to you at all.
Bob
Frank Gonzalez
10-27-2007, 04:29 PM
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Bill
10-27-2007, 04:50 PM
#20
Melting Slicks
There is only one bump in one corner that upsets my ABS on my C4. This is out of 10 different tracks that I've run. Just one location.
The bump must be where I apply the brakes, and 1 wheel must get light, and I can feel the ABS virbrating the brake pedal.
The answer is to simply lift off the brake pedal for a split second when you feel that ABS problem, and then re-apply.
It's not a fluid issue, and not a pad issue. Just lift and reapply by squeezing the pedal, not jabbing the brakes.
as far as flushing fluid before and after every event..... that is a bit on the obsessive side
The bump must be where I apply the brakes, and 1 wheel must get light, and I can feel the ABS virbrating the brake pedal.
The answer is to simply lift off the brake pedal for a split second when you feel that ABS problem, and then re-apply.
It's not a fluid issue, and not a pad issue. Just lift and reapply by squeezing the pedal, not jabbing the brakes.
as far as flushing fluid before and after every event..... that is a bit on the obsessive side