[Mark C]

I've been all over these boards, can't find a good answer anywhere.

I've bought an AVIC-D3 nav system and need to tap into the VSS wire. From what I've read, the true VSS is in the CAN-BUS, but there IS a shaft speed sensor that works just as well. The regular MZ3 owners have been able to tap into a 2-wire harness on top of the transmission, behind the engine.

There must be a helluva lot more room behind their engine than ours, because I can't even see back there, much less reach a sensor. I'm hoping there's another way to do it, or that location is different on the Speed3's (the reason I'm posting here and not in the audio category). Has anyone successfully found a speed sensor on a Speed3?

 

[leofaye]

[quote author=Mark C link=topic=72085.msg1269268#msg1269268 date=1173976770]
I've been all over these boards, can't find a good answer anywhere.

I've bought an AVIC-D3 nav system and need to tap into the VSS wire. From what I've read, the true VSS is in the CAN-BUS, but there IS a shaft speed sensor that works just as well. The regular MZ3 owners have been able to tap into a 2-wire harness on top of the transmission, behind the engine.

There must be a helluva lot more room behind their engine than ours, because I can't even see back there, much less reach a sensor. I'm hoping there's another way to do it, or that location is different on the Speed3's (the reason I'm posting here and not in the audio category). Has anyone successfully found a speed sensor on a Speed3?
[/quote]

I'll be darned. Woudn't the GPS satellites calculate your speed and show you that on the aftermarket NAV screen?

 

[Mark C]

[quote author=leofaye link=topic=72085.msg1269302#msg1269302 date=1173977884]
I'll be darned. Woudn't the GPS satellites calculate your speed and show you that on the aftermarket NAV screen?
[/quote]

Yes, but the nav system uses the VSS for increased accuracy. From what I've read, the positioning can vary as much as 1/8 mile without it, and ~50 ft with the VSS connected.

 

[superjudge]

[quote author=Mark C link=topic=72085.msg1269510#msg1269510 date=1173983929]
[quote author=leofaye link=topic=72085.msg1269302#msg1269302 date=1173977884]
I'll be darned. Woudn't the GPS satellites calculate your speed and show you that on the aftermarket NAV screen?
[/quote]

Yes, but the nav system uses the VSS for increased accuracy. From what I've read, the positioning can vary as much as 1/8 mile without it, and ~50 ft with the VSS connected.
[/quote]

Damn that's quite a difference, nice find!

 

[Mark C]

Any ideas? I called my local dealerships, they want to charge me shop time to locate the wire. I don't need it THAT badly.

 

[mattleegee]

The wire is on top of the transmission?

 

[Coulda]

my tom tom has never been farther off than 100 feet and that was with only 4 sats connected...when i get 12 im within 10 feet easy. I wouldnt worry about the hassle unless you want some sort of bragging rights with friends or something.

 

[MrTea]

i thought the AVIC units used that reading so you couldn't view while the car was moving, not to corrilate with GPS stuff?

sorry, i'm no help, i didn't even know the reg. 3 guys found a wire to tap into?

 

[Mark C]

[quote author=Mattleegee link=topic=72085.msg1274660#msg1274660 date=1174243894]
The wire is on top of the transmission?
[/quote]

Yup, which is buried below the turbo and other assorted Mazdaspeed3 parts that the regular 3 guys don't have to worry about. I can barely see the damn wire, let alone reach it and tap it. It's got to come back to the ECU somewhere, I just don't know where. I could try putting the car on ramps, but it's 35 degrees outside and snowed yesterday, so that'll have to wait. I found 1 brown wire in each of the harnesses, but I'm a little uneasy randomly tapping wires hoping to find the right one.

As for accuracy, it's not bad, I'd say maybe 100 ft now. However it gets confused when making a turn at an intersection with a parallel road nearby. It's put me on the wrong road a few times, but recalculated pretty quick. This isn't essential, but I feel like my install isn't complete until I find the damn wire.

 

[mattleegee]

what about below the intake where all those wires are to the tranny?

 

[IvanHoe]

[quote author=Mark C link=topic=72085.msg1269268#msg1269268 date=1173976770]
I've been all over these boards, can't find a good answer anywhere.

I've bought an AVIC-D3 nav system and need to tap into the VSS wire. From what I've read, the true VSS is in the CAN-BUS, but there IS a shaft speed sensor that works just as well. The regular MZ3 owners have been able to tap into a 2-wire harness on top of the transmission, behind the engine.

There must be a helluva lot more room behind their engine than ours, because I can't even see back there, much less reach a sensor. I'm hoping there's another way to do it, or that location is different on the Speed3's (the reason I'm posting here and not in the audio category). Has anyone successfully found a speed sensor on a Speed3?
[/quote]

is that a double din unit??

 

[Mark C]

[quote author=IvanHoe link=topic=72085.msg1276520#msg1276520 date=1174325971]
is that a double din unit??
[/quote]

Yes. I still have to mount the rearview camera (and find a speed sense signal). Hopefully this weekend I'll get that knocked out and post some pictures of the entire install.

 

[bani]

the need to tap into shaft speed sensor is so the gps can do dead reckoning. my garmin can go down to about 10 feet on the standard antenna, but if you go into a tunnel you're screwed. that's what dead reckoning is for.

 

[Mark C]

I'm going to try tapping the wheel speed sensor. Found the wire, kind of a pain to get to from under the hood, and it started raining tonight so I didn't feel like taking a wheel off. I'll post back results when I get around to it.

 

[Coulda]

My TomTom has a gyro(or something) that allows it to estimate distance when its not connected to the sats. Garmin's dont have this?

 

[sgon]

\\

have you tried the wires to the speedemeter

 

[bani]

[quote author=Coulda link=topic=72085.msg1278248#msg1278248 date=1174392448]
My TomTom has a gyro(or something) that allows it to estimate distance when its not connected to the sats. Garmin's dont have this?
[/quote]

that only lets it dead reckon direction, not distance.

 

[Mark C]

Still no luck. The wires to the speedometer are CAN-coded wires I'm told. I tapped the wheel sensor AT the wheel, neither wire worked. I'm getting close to giving up....

 

[sgon]

well if your looking for the wire for speedemeter its the white wires its the right plug wires its same wires as the OEM nav is using,

also have you seen this tread, check out the installation instruction of the dash kit

http://www.torontomazda3.ca/forum/showthread.php?t=16263

 

[Mark C]

That set of instructions is helpful, gives me a little more hope. I'll try that location next. I'll have to figure out what wire connects to that location and tap that, instead of inserting a 'pin' into the harness. I'm surprised it locates the reverse signal all the way at the rear of the hatch. That's where I put mine, but there has to be a spot at the dash also.