Need abs sensors


#1

I need about 5 rear sensors and 2 fronts to get the abs on the ix and the spece30 working. I wanted to get the abs on the ix working last week, but all the sensor wires and connectors are rotten. The same situation on the spece30. The abs works for a minute at the most before light comes on. Resistance at the harness was 950 for all 4 sensors sitting in the garage. My brothers suggestion was to hook up a meter to the harness one sensor at a time, drive around and watch the meter until I see a break in the signal, but I would be surprised if it wasn’t all four of the sensors being intermittent. At 150$ a piece I definitely won’t have abs working anytime soon. I found 2 front sensors on craigslist for 5$ each but one shows an open circuit when I put a meter on it. It’s to cold for junkyard hunting up here now. I assume it’s impossible to replace the sensor leads since the sensors look pretty well sealed.


#2

You can replace the wiring between the sensor and connector. V=Clip the wires close and use solder & heat shrink tubing.


#3

That’s a good idea since the sensors themselves have no moving parts and should pretty much last forever. But if you really need to buy some, I checked ebay and the best deals seem to be coming from some guy calling himself bmwspareshop in the UK. $30 for two shipped.


#4

Where would I get the connectors? Does the ABS computer care about the polarity of the sensors? The previously white plastic connectors fell apart and now I just have The seperate wires with with the female ends crimped on covered in electrical tape.


#5

Where would I get the connectors? Does the ABS computer care about the polarity of the sensors? The previously white plastic connectors fell apart and now I just have The seperate wires with with the female ends crimped on covered in electrical tape.[/quote]

I don’t think that the sensors care about polarity so you can’t get the wires switched. The gear shape of the hub spinning past the magnetic sensor creates a sine wave signal across the two wires. No matter which wire is grounded, the sine wave signal will be the same.

The wires are unmarked and look exactly the same, correct? That supports my guess because no one would design something using identical wires that had different functions. Identical wires are too easy to get mixed up during mfg and repair.


#6

Scott is correct!


#7

I think there was one red and one black wire and plastic connector only goes on one way if they still exist. I may buy the sensors on ebay, but judging buy the color of the connectors they are in rough shape. The ix uses four rear sensors anyway.

FYI: ix abs computers can’t be used on any other e30 because it uses different pins in the harness. The ix abs also has a deceleration sensor and the 88 ix limits engine braking via the ecu on low traction surfaces.


#8

While that is true in this and 99% of cases, I’d just like to point out an annoying repair I had to make on a friend’s Chevy truck’s blower motor resistor. 7 wires into the connector, 3 black, 4 white. Naturally, the resistor tends to blow and melt the connector so splicing in a new pigtail is a common repair. Assumption of logical design cannot be applied to GM products.

That’s very smart, since my brother once spun his '89 auto convertible while coasting down an icy hill at ~35 mph in 3rd gear. The slight tug of engine braking was enough to break the rear end loose and spin us 180.


#9

Saturday night I achieved victory over the abs system on the ix. I appears that the relay was the only problem in the first place. I created the second problem when I disconnected the front sensors and the plugs disintegrated. I did a poor job of taping up two wires and they were able to short together. A little shrink tube over the wires was all it took. The unanswerable question is why did it take 10 minutes of driving for the abs light to come on the morning that I fixed the relay. I have no doubt that it didn’t just burn out then because it had already been coming on. The other questionable thing is that my brother sent me a service bulletin saying that the 88iX has to have a motronic 1.1 for the abs to work or it needs a special adapter installed at c101. There is no adapter harness installed at c101 and my dme is a 261 200 380, which is listed in the spece30 rules as a 1.3.


#10

Apparently she still has some fight left in her. Yesterday the abs light stopped coming on during startup, but I can still feel the abs working on my icy driveway intermittently. I wouldn’t be suprised if tomorrow the light comes on at startup and goes out like normal. Could this be an SI board issue.


#11

The SI board has nothing to do with the ABS light.


#12

Sorry to revive an old thread but in my research this seemed like the best place to start on my current issue.

When I bought this car the PO said the abs was not working due to a bad sensor. At 130$ a pop I can see why he was not interested in changing them. Using the diagnostic technique described here and on the other sites I have confirmed it is most likely a sensor issue. I have driven the car since then without the abs and it has been a non issue.

While prepping the car for the next HPDE I swapped in track pads. The new pads grip significantly better and I had a couple of lock ups initially until I got used to the bite. No biggie but if I can get the abs system up and running I think I will prefer it.

I agree with the idea of the above quote, there are no moving parts in the sensor. Assuming the magnet is not fouled or the internal connections have not been broken bad sensors probably have more to do with broken wires or connectors.

This though seems to be the only reference of this type of fix…is this in fact standard practice or due most just pony up and buy new sensors?

Regards,

Miguel


#13

Sorry to revive an old thread but in my research this seemed like the best place to start on my current issue.

When I bought this car the PO said the abs was not working due to a bad sensor. At 130$ a pop I can see why he was not interested in changing them. Using the diagnostic technique described here and on the other sites I have confirmed it is most likely a sensor issue. I have driven the car since then without the abs and it has been a non issue.

While prepping the car for the next HPDE I swapped in track pads. The new pads grip significantly better and I had a couple of lock ups initially until I got used to the bite. No biggie but if I can get the abs system up and running I think I will prefer it.

I agree with the idea of the above quote, there are no moving parts in the sensor. Assuming the magnet is not fouled or the internal connections have not been broken bad sensors probably have more to do with broken wires or connectors.

This though seems to be the only reference of this type of fix…is this in fact standard practice or due most just pony up and buy new sensors?

Regards,

Miguel[/quote]

Where are you located? Perhaps someone has a set of used sensors that you can try?


#14

There are a couple of tests that I will run the next time I am at the shop. I think there open impedance is 960 Ohms or something…that would be the easiest test. Next you can unplug 3 of 4 and roll down the road and see if the light is triggered. As you move wheel to wheel this way a triggered light indicates a working sensor, no light is a non-working sensor. I am assuming at least one is not working and that I can identify it through one of the above mentioned tests.

I am really looking for a repair method other than replacement. The ebay and uPickit routes are also available but you are replacing an old bad sensor with another old (maybe bad sensor).


#15

Adjust your brake balance with pad compounds and learn to drive w/o anti lock…you’ll be faster.


#16

I was under the impression that the abs system needed to be operational to comply with the spec rules. Seems like some people run with some without.

Looked at the sensor connectors and they are wasted. They crumbled away in my hands.

I have not had any more wheel lock up since the initial roll around the block so I am just going to leave it alone for the moment. If I decide to try to replace the wires on the sensors at some point in the future I will report back.

Miguel


#17

ABS equip needs to be in place. Doesn’t need to function tho.

I’d get a couple from the local picknpull. I agree that failed sensors are usually failed wires on good sensors. If the connectors are falling apart, clip them off and hardwire them.


#18

Please point out the section in the rules that allows the ABS to be non-fuctional or disabled.


#19

Please point out the section in the rules that allows the ABS to be non-fuctional or disabled.[/quote]
It’s common sense. You think your parking lights are required to function? Headlights required to function? Fuel gauge required to function? O2 sensor required to function?

The rules tell us what we are required to modify and allowed to modify. They really don’t address what we are “required to repair”.


#20

Parking lights & fuel gauges are not a potential performance enhancements. Older ABS systems are far from ideal in dry conditions and a skilled driver can outbrake ABS especially when a stop to zero is not required.

My reason for commenting is that perhaps it’s something that should be clarified in the rules.