It seems like ever since I installed this aftermarket torque arm, I just cannot get my ABS to activate. On dry pavement in a straight line, I can put the pedal to the floorboard and it'll stop hard - but the pedal doesn't pulse nor does the ABS light come on.

In a damp straight stop from about 30-40MPH, it'll stop pretty hard, but the last few feet the LOW TRAC light lit on my dash - and I would have through the ABS light should be lit instead.

Is it possible something is not corrected properly, or might the design of the torque arm be responsible for the inactivity of the ABS? The TA I've got emulates extending the length of the TA all the way to the front tires under braking, but under acceleration the arm is shorter than stock and doesn't connect to the tranny.

I'd just feel better if I could get it to activate

 

If your abs is not working your abs light should be on because your computer should ditect the abs being inop unles your bulb is out in your cluster

 

Hmm, even if the bulb was burned out, the ABS should still function and the pedal should still pulse. So why would I get the Low Trac indicator without any ABS activation during hard braking?

 

The low traction light is coming because the system is detecing low traction I dont think the abs will come on at the same time when braking hard but you should scan your computer for any abs codes or problems.I dought your bulb is out but to check it just turn your key and see if it lights up or maybe your abs pump is not working their for not makeing your brakes shuter when braking hard but I am sure that if you had any abs problems it would set your abs inop light on

 

The ABS will only activate if one or more of your wheels is slipping. If you've got good brakes and can stop just fine on dry pavement by mashing the pedal, it's not going to activate. When it does activate, the "low traction" light will come on, not the ABS light. The latter illuminates when the system is disabled due to a problem detected by the EBCM/EBTCM.

If you want to see if it works, wait until the pavement is wet, then nail the pedal from a 50 roll or so

 

The low trac light will come on if you are in ABS. The ABS light will only come on if there is a problem. If my memory is right and this morning, who knows.

 

off tiopic, but how was the instal on that UE TQarm. Was it worth the cost?

 

It was a bit of a hassle due to the unusual nature of the setup and my car not being lowered. Easier if you do it on a lift and remove the driveshaft.

I've never used any other aftermarket torque arm, so I can't compare to anything other than stock. I installed it in December, and only got the brake link set right about a month ago. Ever since then, I haven't been able to cause any brake hop - and short of my concerns about ABS kicking in, I've not had any braking problems which can't be attributed too much negative camber. I haven't noticed any gain in traction from a stop.

SFA the ABS, it sounds like moving the instant center from behind the tranny to the front contact patch when the TA decouples might be giving me better brake traction, and also not allowing the rear axle to hop.

 

The low traction light is coming on because the ABS is active due to wheel slippage (Low Trac = wheel slippage = ABS regulation). The ABS comes on because he's braking hard. If the hydraulic pump stopped working, the ABS Inop light would come on and ABS would be disabled. If the ABS went into a regulation event and the pump wasn't working, the brake pedal would sink to the floor and you'd be screwed. Since ABS 5.3 is solenoid controlled, the pulsations are slight and may or may not be felt through the brake pedal. If you see Low Trac light up during braking, the ABS is working.

 

If the pump motor dies, the ABS regulation is ended immediatly. This still leaves you with EBD, so it behave like a car with no abs and a mechanical proportioning valve. Your pedal will not go to the floor as TooSlow02 states.

Brakes are a safety system and has strict regulations by the federal government so situations where your pedal goes to the floor don't occur.

By the way, there are errors that will not set an ABS Inop light. The brake lamp switch is one.

 

I am well aware of federal safety regulations regarding vehicle systems, since I have to deal with them frequently. I am also well aware of the fact that regulation will end immediately when the motor fails. That was the third sentence in my last post. My point is that hypothetically, if the ABS was allowed to continue regulating in the event of a motor failure the pedal would sink to the floor because all apply pressure from the master cylinder would be bled off. This is why ABS is shut down in the event of a pump motor problem.

BTW, in a perfect world, situations where your brake pedal goes to the floor would not occur. And they shouldn't. But I've met a few (thankfully, very few, but a few more than I should have) clients of a luxury car manufacturer who may disagree with you on that one.

 

Hypothetically, it would depend on the motor failure. The failure I am sure you are refering is a state of OFF. In which case, the pedal would go to the floor. As to how quickly depends on many variables.

Let's not bring in other vehicles. Every manufacturer implements the features to meet saeftey regulations differently. Each uses different combinations of software and hardware which results in different degrees of severity, occurance, and detection.

 

I hadn't really thought about it, but if I "kill" the motor (pull a wire off? Can I get to it to do that?), the EBD will still work and I will be ABS free without the EBD problems? I'll leave the block in the car (I'm not in this for weight savings), but I'd love the ABS function to be gone and just keep the EBD working.

Interesting.

 

Yes, the most common symptom of a failed electrical actuator is that it doesn't work. I've never seen a motor that is externally switched fail ON. Something usually has to turn it ON. Stranger things have happened, though. Hell, I even hear they're selling fast Neons now.

And while it's true that different manufacturers do things in different ways, brake hardware and features are the one thing that is markedly similar in very different cars. And they all have to meet the same criteria for safety. So comparing vehicles from different manufacturers isn't really out of the ordinary. The same scenario holds true whether you are talking about a six-figure sports car or a lowly econo-box (provided you opted for the optional but available ABS in the latter).

 

First, the pump motor on the F-bodies is switched by the ABS ECU. So, internally to the unit, but not the pump motor itself. And there are failure conditions that could keep the motor running.

Different designs have different criteria they must meet. The end goal is to meet the same overall goal, but each company uses different solutions. An easy example is a uni-body versus a body on frame. The same is true with different ABS units. The goal of ABS is the same, but the designs are quite different. One company might detect a failure with hardware and the other software. Due to design, one might have a failure condition that the other does not.

Its obvious your not an engineer if you believe that brake hardware and features are markedly similar. Powertrain controls are less complex than brake controls because powertrain is not a safety system. If your engine dies, you pull over to the side of the road. If your brakes go out, someone could die because they hit a wall at 50mph.
You need to trust me on this, an ABS unit in an econo-box is not as safe as a luxury car from the view you take. There are more safety features for keeping the car under the drivers control than in an econo-box.

Your thinking is great for most people. I work on ABS for a living and can't afford to think like you. Some times I know too much about it.

 

Exactly. Motors don't fail on. Motors fail off. Failed motor controllers may turn it on, but we weren't talking about them.

You're kind of going off on a tangent here. The marked similarity I spoke of is simply that the actual hard parts are similar from vehicle to vehicle. They have calipers, hydraulic lines, hydraulic units, a brake master, brake fluid, etc. So the econo box might have a hydraulic pump just like the luxury car. That same motor may fail in either car and produce the same theoretical results that we discussed earlier. But that hypothetical situation is what we were discussing. After I made the crack about being screwed, you said the brake pedal could never go to the floor. I know better than that. I've seen it happen, and it isn't pretty. I never said and certainly never believed that all brake and stability controls are the same, in their design or in the execution of that design. As for failure detection, I'm pretty sure that most all ABS systems will recognize if the pump goes. If not, the car might happen upon that wall you mentioned.

Uh-huh. You mean like the reverse-torque reduction function that was a little too sensitive and caused quite a few accidents by opening the throttle that the driver no longer physically controls rather unexpectantly? Or the brake assist function that saw a quick but light pedal apply and decided to increase brake pressure to maximum so the ABS would kick on, which caused them to get rear ended? Do you mean those safety features? How about the stability control module that decided to open all the outlet valves at once and keep them open for no reason? I guess the module had some homicidal safety features programmed into it. No, you're right in your assumption that I am not an engineer. I just have to deal with engineers on a regular basis because I'm one of the guys that not only has to correct these issues but also explain to the vehicle's owner why it happened in the first place, but without being able to divulge any information that might get the manufacturer sued. I guess it's made me a little pessimistic about these "safety systems". I'm not trying to offend or insult any engineers, or pretend that I can do their job any better. The ideas are sound, but perhaps they can stop choosing parts suppliers by how low the bid is. I hate to think I could be killed because of a cheap part made in Taiwan. Well, enough bitching.

 

First, there ARE pump motor fail conditions where it can fail ON. Sure, not as likely to happen as the OFF condition, but it does exist.

Second, my point is that a pump failure in one car does not guarantee you the same results in another car. Hence, where the design of the system comes in. Depending on the design, sure the failure was detected, but that doesn't meen anything can be done about it.

Third, the throttle relaxer for traction is a systems for limiting torque to the wheels. The end goal is the same as any other traction system. It is just a different traction system. If you believe an accident was caused by it, then you have to believe any traction system would do the same since they are all limiting power.

The panic stop feature is to help prevent accidents. In many studies it has been shown that most people in an emergent stop do not apply full brake pressure immediately. The algorithm uses inputs of pedal distance travled and speed traveld to detect such a situation and help avoid an accident.

You can blame the vehicle and its systems all you want, but in the end it is the driver. If you drive recklessly, no system is going to save you. Take your throttle-relaxer for example. If a driver puts himself in a bad situation, the throttle-relaxer kicks it and an accident occurs. Why did the throttle-relaxer pull power? Loss of traction, right? If traction didn't kick in to help regain traction, how would the out come been different? What's better, less power and traction or full power and no traction? What you need to keep in mind is that the driver put themselvesin the situation by making a bad desicion.

Basically, learn as much as you can about the car you drive. Know what to expect from the car and how it will behave. Its great you can buy a car with all the safety features in the world. But if you don't know how use them, you can make things worse than by not having them. Like pumping the brakes defeat ABS, remember that and the news reports about all problems people had? People needed to be educated to stand on the brakes and let the ABS do the work regardless of the pulsation they felt in the pedal. Maybe the manufactuer or dealer should educate the buyer instead of just trying to make a buck.

"How about the stability control module that decided to open all the outlet valves at once and keep them open for no reason? I guess the module had some homicidal safety features programmed into it." Not even going to go there as it is basically going back to design and safety regulations. Get used to stability control though as the trend is for it to be on all trucks and SUV's. All future truck and SUV products for GM and Honda will have stability control.

Cheap parts? Not sure where to begin on that one. Everyone trying to make a profit and consumer's wanting more while still paying less. OEM's still enforcing better and better quality and reliability. Compare a car now to one 10 years ago. Figure in inflation and which one is more reliable for the money?

I understand how you feel about engineers. I deal with them myself, and hate to admit I am one at times, and most are very detached from the "real" world. But keep in mind the limitations they must work in(money, time, resources, customer requirements...). As it is said, if you don't put limitations and restrictions, the product would be perfect, but no one would be able to afford it. I find it amazing some OEMs can even build a car at all. I should say who, but I mentioned it earlier and it isn't our favorite OEM.

It appears we are the only ones interested in this. If you care to continue this or similar discussions, shoot me a PM and I will give you my email address. I have enjoyed this, but need to watch the content I post due to my knowledge of Bosch braking units.

 

You're still out in space. Again, hypothetical situation. It can't really happen.

No, actually this isn't about a throttle relaxer. The throttle is electronically controlled, no cable. And the function I was referring to OPENS the throttle when it operates. It speeds up the rear wheels when it detects excessive engine braking causing the rear wheels to go slower than the fronts, like in ice or snow when you let off the gas. Only this happened on dry pavement with no cause. Because there was a "miscalibration" in the software.

Yes, thank you, I'm aware of how the system works and what inputs it uses and what calculation it performs. I'm also aware that the low threshold of the system has caused it to operate when it shouldn't have. On many different vehicles.

Well, it wasn't me who decided the system was at fault. It was the engineers who originally f*cked it up who decided that. Them and all of those injured people who have no clue how they ended up driving onto a building. And
again, it didn't relax the throttle. It opened the throttle and sped the car up and made the idiot driver(s) panic and steer into the nearest immovable object. If it was the driver's fault, why did it happen on so many of the same model vehicle under so many different conditions? See, you are assuming that these systems are behaving normally. I trying to explain to you that they are not. The drivers who got rear ended applied the brakes quickly and lightly-but the system intervened. And again, why did it happen on so many vehicles? Why did our engineers freak out when they heard about it? Why did it need to be "fixed" if it was the driver's fault? Why did we have to install an update patch to raise the the intervention thresholds on so many cars? The driver is at fault 99.99% of the time. But these particular instances are the 0.01%.
They are the result of a car company in a hurry.

Don't get me started on trying to educate people about their cars. The phrase "pissing upwind" comes to mind. People learn what they know about cars from movies. Maybe if they didn't think that they knew everything already, they would be more open to "product knowledge". The vast majority of car owners don't even know that the car has an owner's manual. I think I've met four or five of our owners who have actually read theirs.

Design and safety regulations? What are you talking about? This is the one that shoots your "the brake pedal can't possibly sink to the floor" agrument right in the ***. The control module opened all of the brake hydraulic circuits' outlet valves at the same time for no reason when the car was doing about 90 down the highway on dry pavement with no brake pedal input. As a result the car's owner **** themselves when the brake pedal SANK TO THE FLOOR. On a brand new car. No warning lights, no system faults stored. I could put that module in any other car and have it do the same thing. I think this one got by your precious "safety regulations". It wasn't the only one to do it, either. It wasn't even a miscalibration. It was what we call a f*ckup.