ABS question

[Z Ya Later]

Ok, I'm going to see if I can get this figured out once and for all. The ABS is really starting to tick me off. Here's the background, for those who missed it:

When I bought the car, the prev. owner said that the ABS has been acting up since he took it to a concert. Said when he came back afterwards, the dirt lot had been turned to mud (why he would park it in the dirt is beyond me). Ever since, the ABS would either go to INOP or would start pulsing the brakes when slowing to a stop...at around 15 the front brakes would release (rears are fine) then grab again about 5. He had the stealership replace the front right speed sensor and said it went away, but came back after a short period of time (few weeks, couple months, something like that). Well, once I bought the car, that was my first endeavour. I bought Joe's hubs (Joe 1320 that is) and put them on. At first, it was fine. But, later that day it went back to the same old thing. I've even had it pulse the brakes at 55 MPH!!! I've swapped the front right sensor 2 times now and still nothing. I replace the jumper harness for the front right sensor and nothing. So, I'm down to the second harness that the jumper connects to and the Brake Control Module.

So, here's my questions to pose. 1) Which is it more likely to be, or should I consider doing both? 2) If its the harness, is it a main harness that connects the BCM to multiple points (sensors and such)? If so, how much of a PITA would that be to do or should I let a shop do it? 3) If its the BCM, is it as easy as it looks to swap it? 4) What are the part numbers for these pieces? I'm pretty sure I've got the BCM # around, but the harness I cannot find. Thanks a bunch guys and have a good rest of the weekend.

[Injuneer]

Have you ckecked the rear sensor, top of the differential housing? I've had some fairly strange things happen to the ABS when the sensor in my Strange 12-bolt acted up.

[RangerBob]

Did you ever get the brake fluid changed. Isn't it possible that air is in the system?

[Rob B (shoebox)]

If this is on a 1993, you don't even have a BCM (only 1996 and later). The ABS has it's own computer (EBCM) - a different animal from a BCM.

[Joe 1320]

Steve, do as Fred suggested.... check the sensor connection on top of the rear differential housing.

[Z Ya Later]

Thanks for the replies guys. How hard is it to get to the rear sensor? Can I get it with the car down or do I need to raise the chassis, letting the rear hang? Could air in the front right brake line cause this problem also, as Bob suggested? And, is it just referred to as a the ABS controller then? (stupid question, I know lol ). Thanks a bunch for the help. Take care and have a great day.

[Injuneer]

EBCM = Electronic Brake Control Module.

[Z Ya Later]

EBCM = Electronic Brake Control Module.

Oh, 1 letter. Sheesh, picky picky lol j/k

Seriously, thanks for the correction Fred and Rob, its much appreciatd . So, how hard is it to get to the rear sensor? Can I get it without having to raise the chassis? Thanks everyone for your help so far.

[Injuneer]

Whenever I worked on mine, I jacked the car, put jackstands under the subframes, and let the axle go to full drop. There is a wiring harness that connects to a block on the bottom of the kick-up over the axle. Might be sort of hard to get to without jacking it up, but I never tried it that way.

[Z Ya Later]

Alright, I give that a shot either tomorrow or Tues. Say that the rear sensor is fine, what would be next? Figured I'd ask so I can go at this with a checklist. Any other ideas or am I looking at a very expensive problem? Thanks for the input and the help guys.

[Injuneer]

Don't know. The Strange 12-bolt uses a unique adjustable sensor. If you don't get the clearance to the reluctor gear EXACTLY right, the ABS won't work right. Sometimes the "ABS INOP" light would come on and stay on. Other times the system would work fine, except at about 5-10mph the ABS would kick once or twice (not sure how you are determining its the front brakes on yours) and then turn off just before the car stopped. Soundsvery similar to your problem. Made stopping short in traffic an adventure, because the car always went about 10 feet farther than I planned.

Have you ever had the EBCM scanned by a competent brake shop?

[Z Ya Later]

That actually sounds dead on to my problem. The reason I think its only the front brakes is because, at least from my perception, the car still slows down and the pedal is still firm if I let off and press it again. Also, I can hear the front calipers releasing and then grabbing, but nothing from the rear. Even on a downhill slope the car still slows down when it pulses, just not as much. I'm not saying that I couldn't be wrong on this, because if it is the rear sensor that makes the determining the problem much easier. I've had the stealership scan it as has the prev. owner at a different stealership. Both came up with the front right sensor, which is what led me to believe that it was a problem with the sensor or the wiring to it. Now, what should I be looking for on the rear sensor? Loose connection is obviously one, but can I wiggle the sensor to see if its not set properly or something to that effect? Thanks a bunch for your help Fred, esp. in these early morning hours lol. Take care and have a great day everyone.

[Mike71]

i can just see steves next post..ok so i wiggled the conector, how much is a replacement because i broke it off tee hehe..hey if u need help its not like i have anything better to do lol ur only like 1hr away to

[Injuneer]

The stock rear sensor isn't "adjustable". One possibility is that is is coated with metal particles or the hole is gunked up with lube and metal particles. Might be worth pulling it out and cleaning it off.

If the scan says its a front sensor, it would appear you have looked at all the options. One possibility that gets overlooked is interference from a high voltage wire like an ignition wire. If you have a plug wire running too close to the sensor wire (can't imagine that happening), it can induce spurious noise in the ABS signal and screw with the EBCM computer.

[Z Ya Later]

Hey, I'm not that incompitent with this thing lol . Thanks Mike

Fred, there's a good 2+ inches between the ABS wires and the plug wires. The prev. owner said he had the tune up done before the problem started occuring and didn't have a problem before the aforementioned concert. I did noticed that the old jumper harness had bare spots at the sensor connector on both wires, right where the wire meets the molding for the connector. Is it possible that it somehow damaged those pins on the EBCM?