I have a 93 wrx, it reads in MPH, a converter was fitted when it was imported, where would this converter be and how does it work?

Cheers

dave

 

Your converter is mechanically driven off the gearbox, you will find the converter closest to the gearbox to the right of the downpipe or behind the clock.

 

Thanks for the reply,

So it's a mechanical device that slows the actual spinning motion of the cable going to the clocks on the dash?

how does the speed signal going to/from the ecu get changed by this device?

 

There is a tiny sensor screwed into the back of the speedo head near where the cable plugs in.

This sensor picks up a signal from the spinning motion of the mechanism driven by the cable.

 

Ahh ok thanks for that!

And do you know how i could test this signal, i've seen somewhere it pulses between 0 and 5 volts, does the frequency of the pulses increase with speed or something?

Dave

 

Yes the pulses increase with speed, but the ecu does not need to know exactly how fast you are going, it just needs to know that you are moving.

Why do you want to test it? Are you in limp home mode & have fault code 33 (vehicle speed sensor) logged in the ecu?

 

I am trying to figure out why my AVC-R displays the speed inconsistantly, it jumps from the actual speed to a much lower number while driving. It jumps constantly and very quickly.

 

Ahh, I see the reason for the questions now... I'm afraid I have never measured the signal over a range of road speeds so can't give you figures that your after. Sorry.