ABS works only when it wants to?

[MrMazda92]

The title is vague, yet probably the best description...

My ABS on my '93 GS doesn't always work, and I managed to lock the wheels and turn sideways on the freeway once at ~80 MPH. Having done this before, I didn't crash thankfully I did get a friendly buffer on all sides from the cars around me though, no tailgating for a while was nice.

I'm basically wondering if there's a fairly straight forward diagnostic technique for this, and if somebody would be kind enough to point me in the right direction.

2 Piston calipers are coming this fall for both cars, which will be nice. I'd like to deal with this at the same time if possible!

[Josh]

This wont help you much BUT, IMO these early model ABS systems are horrible. I would take it out if my car if I had it. The only early mid 90's car i drove where the ABS kinda worked properly was a Dodge Spirit, haha. from what you are saying it sounds pretty consistent with others that I know who have it in their MX-3's.

To trouble shoot I would start at the wheels and work your way to the control module for the ABS. maybe one of the lines to one of the wheels are bad? perhaps something is stuck or needs replacing. sorry i cant be of more help I would have to actually look at it. I haven't worked on ABS to much.

side note- I love the ABS in my RX8 system is amazing over early model systems like the MX3.

[MrMazda92]

I've been fortunate then with my '92 it seems, as it's worked perfectly from the start

It actually locked both front wheels(possibly all 4, I was a little preoccupied trying not to die and all), so I'm inclined to think it's the module itself. That's under the passenger seat, isn't it? I honestly wouldn't know how to diagnose it, and it only seems to happen occasionally... I went out and TRIED to lock the wheels, and it happened in 3 passes out of 10 before a cop pulled me over. He thought it was funny, and just told me to go home. -.-

[Ryan]

You're a well built guy, not?

I think its actually possible to mash the pedal hard enough to cancel out the ABS. In some other models, if you tap the brakes before you hammer down, it also cancels out the ABS...

[wytbishop]

The easy cause of ABS malfunction is the tone rings and sensors. Being down in the elements it's possible for the sensor to rust into nothing. Could be a sensor wire got caught on something and pulled apart. Could be a tone ring got hit by a rock and broke.

Any "gap" in the ABS system will basically turn it off. Is the ABS light on?

Everything else is much worse. There is an ABS section in the brakes chapter of the online manual. There's troubleshooting in there.

[MrMazda92]

Ryan, that hadn't occurred to me... I did hit them hard, an S2000 in front of me floored his after cutting me off; I truly locked the wheels badly enough that the car turned sideways, so you may be right on the money with this...

Wyt, the light doesn't stay on consistently, but it came on twice during my trip home with the car for about 30 seconds each time. Both were while taking offramps to gas up.

[MrMazda92]

You're a well built guy, not?

I think its actually possible to mash the pedal hard enough to cancel out the ABS. In some other models, if you tap the brakes before you hammer down, it also cancels out the ABS...

I want this.