VSS reads very high

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chips60bug
Master MS/Extra'er
Posts: 400
Joined: Sun Aug 31, 2008 10:20 am
Location: Utah, USA

VSS reads very high

Post by chips60bug »

Has anyone else noticed that their VSS reads at least double what it should? Mine both do, front and rear. It has me totally confused. I will get a log up soon. Here is my msq though. Reading the 5 teeth bolting my rotor to my hub with DIYs Hall Sensor.
chips60bug
Master MS/Extra'er
Posts: 400
Joined: Sun Aug 31, 2008 10:20 am
Location: Utah, USA

Re: VSS reads very high

Post by chips60bug »

Here is a quick datalog of me driving through a parking lot in 1st gear. This is not a land speed car, 3100 rpm is not 51mph in 1st. Is anyone else seeing bizarre stuff like this when triggering off of teeth? There are 5 mounting tabs on the back of each rotor.
Do I just have the settings wrong somehow? They feel pretty straight forward to me. Is there a metric to American conversion in there somewhere that I am missing? Thanks for any help you guys can offer.
The car has an MS3-Pro, running 1.5 beta1 firmware.

I have found that putting in a value of 10 teeth helps with the speed. Not sure how accurate it is though.
jsmcortina
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Re: VSS reads very high

Post by jsmcortina »

I've used that feature a number of times and it works ok. Is there any chance that your sensor might be reading two edges somehow?

James
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Rick Finsta
Master MS/Extra'er
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Joined: Fri Dec 10, 2010 4:41 pm

Re: VSS reads very high

Post by Rick Finsta »

I had this same thing happen targeting the rear of the wheel studs on my application. There are little divots in the studs and the sensor is sometimes seeing two events. I was advised to pull the sensor back from the studs until I saw the problem go away, but I have not had time to pull the wheel hub and adjust. Instead I am using the pulses per mile where it is easy to do the conversion math to get the sensor to read correctly based on GPS speed as a stopgap measure.
chips60bug
Master MS/Extra'er
Posts: 400
Joined: Sun Aug 31, 2008 10:20 am
Location: Utah, USA

Re: VSS reads very high

Post by chips60bug »

Okay, that actually makes sense. I have had the feature work fine previously. I adjusted my rear one the other dash and now it reads double, my mounting tabs have a flush mounted allen head bolt in them and i know for sure that the sensor is passing over the keyhole. I didn't realise that would count as an edge. Makes complete sense though. Thanks!
Rick Finsta
Master MS/Extra'er
Posts: 548
Joined: Fri Dec 10, 2010 4:41 pm

Re: VSS reads very high

Post by Rick Finsta »

Hope you get it sorted! Please update if this was the issue.
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