Problem with brakes.

[wiswind]

There will be 2 types of VSS for your windstar.
1 for with a mechanical speedmeter
1 for with the electronic speedometer (LED display)

The mechanical speedometer version......the gear turns a shaft....and the speedometer cable plugs into the VSS.....and the shaft inside the VSS turns the speedometer cable....which in turn spins the speedometer.

This unit (for the mechanical speedometer) also has a electrical part......which has a plug...that connects to a wire harness that goes to the PCM.
This part tells the PCM how fast the vehicle is moving....and the PCM uses this for various things.......one of which is knowing how to control the transmission.

The electrical part failed in my '96 windstar this summer......and the PCM did not know how to control the transmission.

The VSS is not a expensive part....but it is a major pain to change.
It is located on the back side of the transmission......located above one of your catalytic converters.
Changing it is done by feel.......hard to get to......pretty much impossible to see.
Follow the speedometer cable down.......as it connects into the VSS.
The VSS is held in place by 1 bolt.......and has the 2 mentioned connections.....Speedometer cable and electrical connection (for the PCM).
The speedometer cable is in 2 parts.....the part that connects to the VSS comes up and connects to the part that goes to the speedometer......this connection is under the flex hose that goes to the throttle body......might be best to remove the flex hose.....so you can see and get at the speedometer cable connection.

The most likely cause of the jumpy speedometer is internal to the speedometer.....maybe a lack of lubrication?

Perhaps you could do a search on speedometer and if that does not get you helpful results.....start a new thread for the speedometer.
I am sure that others have had the problem.....and solved it.
I had the problem.....but it went away before I got around to messing with it.
Wish more problems were like that.

[zippy_LiL_SL1]

Originally Posted by serge_saati

When you mean erratic readings, you mean that it displays higher speed that the real speed or it displays the lowest speed on the gauge (10mph)? It fluctuates?

I'm sure it's not the VSS cause this one is integrated in the transaxle (not in the wheel like the ABS sensor) and it's very reliable.

But it can be a problem with the VSS wire that connect to the PCM or the PCM itself.

For example, in my first Windstar, when I was going at 100km/h it displayed 113km/h. It was a problem with the PCM.

What I mean by erratic readings is that if I go anywhere over 55 mph, the speedo makes a wierd hissing noise and the needle bounces erratically between about 60 and redline.

[wiswind]

That is exactly what mine did.....I read something about lubrication inside the speedometer as the solution....but did not follow up on it....as the problem went away after a couple of months.
Mine did this in the winter time....so maybe the cold had something to do with it? although it kept doing it for trips over an hour long.
I am still leaning toward this being a issue with the actual speedometer vs the cable or sensor.

[serge_saati]

In the past, I also had another problem with my speedometer. Sometime when I was cruising at about 50km/h, it indicates 20km/h (the lowest value). When I accelerated a little bit (up to 60km/h) it remains working correctly. It happened also in the winter only (below 10°C).

[zippy_LiL_SL1]

Hmmm no this happens regardless of the weather. I've read somewhere that there are gears inside the speedo that get stripped over time. Same thing goes for something inside the transaxle... some gear strips.

I only have about another week to figure this out and then it gets a decorative "For Sale" sign.

I think I'd better start thinking of a good advertising slogan to get rid of this thing because I can already foresee difficulty in selling it.

[serge_saati]

Originally Posted by zippy_LiL_SL1

I think I'd better start thinking of a good advertising slogan to get rid of this thing because I can already foresee difficulty in selling it.

I don't think so. Some peoples are not perfectionism as you and don't look for a perfect condition car. They just need a van for their family or to carry heavy stuffs.

They don't care if the ABS or the speedometer are not working good. Or if the CEL is on. It's a 97, not a brand new car.

The only thing that can frustrate them is the speedometer needle, but I think you can repair it.

[zippy_LiL_SL1]

That's an interesting perspective!

Well I'm just going to get this sensor put in and then that's it.

Oh.. BTW... I put the fuse for the ABS back in, even with the lack of a front passenger side sensor. The ABS light stayed on but the original problem wasn't there. Perhaps I got lucky and found the problem with just that sensor.

[serge_saati]

Originally Posted by zippy_LiL_SL1

Oh.. BTW... I put the fuse for the ABS back in, even with the lack of a front passenger side sensor. The ABS light stayed on but the original problem wasn't there. Perhaps I got lucky and found the problem with just that sensor.

When the ABS computer detects a problem with the ABS, it disables the ABS circuit. So of course, the car will be able to brake normally, cause there's no more ABS. You are in a similar situation as me.

Before you removed the sensor, the computer "thought" that your sensors working good, but they're not. It's why it activated all the time. Your problem is still not repaired. And we don't know which sensor doesn't work fine.

[zippy_LiL_SL1]

Originally Posted by serge_saati

When the ABS computer detects a problem with the ABS, it disables the ABS circuit. So of course, the car will be able to brake normally, cause there's no more ABS. You are in a similar situation as me.

Before you removed the sensor, the computer "thought" that your sensors working good, but they're not. It's why it activated all the time. Your problem is still not repaired. And we don't know which sensor doesn't work fine.

Wonderful.....

[serge_saati]

I just though about something. Maybe it's not a problem with the ABS sensors.
If a wheel decelerates more faster that the other, it may activates the ABS system.
Maybe a tire is underinflated, so it spins faster to get the same speed. So when you brake, it decelerate more quickly. All the tires should be inflated at 32psi.

It can be also a misalignment or 1 brake pad is more used that the other side, which affect the braking.

[zippy_LiL_SL1]

Originally Posted by serge_saati

I just though about something. Maybe it's not a problem with the ABS sensors.
If a wheel decelerates more faster that the other, it may activates the ABS system.
Maybe a tire is underinflated, so it spins faster to get the same speed. So when you brake, it decelerate more quickly. All the tires should be inflated at 32psi.

It can be also a misalignment or 1 brake pad is more used that the other side, which affect the braking.

Your input is appreciated. Right now, however, I just do not have the time to look at it.

I don't know if any tires are under inflated but I do know that the brake pads/rotors are fine. I'm going to make an attempt to get to the j/y sometime this weekend so I can make another attempt at getting that sensor. I never picked up the one I ordered because I cannot justify spending THAT much more money on something I'm just going to sell anyway.

[Airjer_]

I have never had a low/flat tire cause this symptom. At slow speed even a flat tire is providing a speed input. The ABS will engaged if it sees a dramatic drop in its signal from one or more wheels.

[northern piper]

with all this thread has contained I think it's too bad that there isn't some sort of tool or machine () that would allow you to determine which wheel is the culprit....

(my wife calls me a s**t disturber).

[serge_saati]

Yes, it exists a machine that connect to the PCM and read ALL infos about the driving: accelerating, braking, ABS event... It'll tell for which reason the ABS has been activated, what is the speed of each wheel.

When a serious accident occurs, insurances company use this technique to determine what was the cause of the accident.

Unfortunately, not everyone is equipped with such tool.

[Airjer_]

Originally Posted by serge_saati

Yes, it exists a machine that connect to the PCM and read ALL infos about the driving: accelerating, braking, ABS event... It'll tell for which reason the ABS has been activated, what is the speed of each wheel.

When a serious accident occurs, insurances company use this technique to determine what was the cause of the accident.

:sarcasm1:

And you've seen this magic box that tells all?