I've been looking into buying a navigation system for my LS400. The Pioneer units look great, You can get the Avic D1 for a really great price. When searching through the forums about navigation systems, a lot of posts show up about the vehicle speed sensor. I couldn't really find a detailed install post, but as far as I understand, the navigation systems work by using a combination of GPS and vehicle sensors to navigate. But what about on a car like the first gen LS that didn't come equipped with navi? Do they work purely with GPS? I know you can get GPs systems for cellphones that rely just on GPS. But I keep seeing posts about the vehicle speed sensor not working correctly with the car.

So, should I not worry about this? Are there specific navigation systems I should look for, or specific systems I should avoid? Also, that new pioner unit that monitors speed and other car statistics... does it come with its own sensors for that? Do you need some other hardware in the car? Thanks,

- Suneet

 

the speed sensor is going to be more accurate then JUST the gps only. if you can definately hook up the speed sensor wire if you can.

 

esp in tunnels and downtown in the canyons of skyscrapers

 

The AVIC-D1 uses a combination of two methods to accurately determine a car's position.

GPS signals and "Dead Reckoning". The dead reckoning part is the one where you have the speed sensor wire hooked up.

The AVIC-D1 is actually very sophisticated in this regard.

Positioning by dead reckoning (this is taken from the manual - yes I just installed a D1 in my car).

The 3D Hybrid Sensor in the navigation unit also calculates your position. The current location is measured by detencting driving distance with the speed pulse, the turning direction with the Gyro-sensor, and inclination of the road with the G sensor.

The 3D Hybrid Sensor can even calculate changes of altitude, and corrects for discrepancies in the distance traveled caused by driving along winding roads or up slopes. Also, the navigation unit learns the driving conditions and stores information in the memory; thus as you drive more, the precision of the positioning becomes more accurate.

 

So on a car like my 94 LS400, what do I do for wiring for the speed sensor? Do I tap into the cable that goes into my speedometer? Is there an after market sensor I can install and connect to the navi unit?

 

Anybody have an update on this one? For example, if I were to buy the Z1, would it be as simple as tapping into my speedometer wire and running it to the unit? Will it understand the signal?

 

You need to figure out which is the speed sensor wire and that is what is connected to your Z1. I have the D1 and it has a wire that you connect to your speed sensor. I am sure the Z1 will also have such a wire.

 

I can't tell you where the VSS wire is on your car, but I assure you there is a VSS wire on your car. With the double-din kits out there these days, any audio shop can probably hook you up. The cost of the Z1 is a helluva lot of money to to risk with a DIY job if you don't know your way around behind that dash. My advice is that if there is any doubt in your mind, get some help.

On my GS, the installer found the wire -- as documented, he says -- in the power steering control box behind the kickbox on the driver's side. The point here is that it was documented, and I assume the installers have documentation on your car.

My install was complicated because I was unplugging a custom install for a Pioneer P9 head unit and the stock harness had been pulled out. I needed someone who could figure out what the previous installer had done. There were anxious moments, but it turned out fine.

As for the Z1, well it's the only thing out there that would cause me to give up the P9. Voice activation -- and hearing the actual name of the street, not just "Right turn ahead" -- takes navigation to the next level. And it is really nice to be able to use voice commands to find a gas station, a street address, dial a telephone number, or search for a tune on the hard drive.

Yes, there are some shortcomings. But it is a helluva head unit. State of the art at the moment.

 

Thanks for the clarifications. That was the main thing I was asking. Is the VSS wire always there, and is it the wire that feeds my Speedo. I'm goign to get a set of repair manuals and electric manuals shortly, so if I do the installation myself, I'll see if I can locate the wire from those.