Speed sensor wire from/to ECU?

[robains]

Does anyone know which wire the speed sensor wire is from/to the ECU?

This is on a 07 Exige S.

Thanks, Rob.

[elise/europa]

All sensor are passing throught the ABS controller, and goes to the ECU. 8 wires to ABS, 4 to ECU. I know that one is giving the speed for the speedo, I don't remaimber which one, but you can find it on forum.

[turbophil]

Originally Posted by robains

Does anyone know which wire the speed sensor wire is from/to the ECU?

This is on a 07 Exige S.

Thanks, Rob.

As mentioned, there are 4 wires going to the ECU for speed. They run down the spine/center console of the car, through the grommet under the air box and join one of the harnesses that goes to the ECU.

All 4 are different shades of lime green. LG/silver, LG, LG/YLW, can't remember the 4th one... Nevertheless, they're not all that great for monitoring speed unless you have a super sensative datalogger, as they pulse like 32 times per revolution. That's about 24,000 pulses per mile which is way more pulses than what most data loggers like. About 80 mph will overwhelm some loggers out there, as most wheel speed sensors pulse 1-4 times pre rev_ not 30+ times... In addition, that many pulses creates potential for a lot of noise in the speed signal as well.... You can purchase the OE celica speed sensor that goes in the tranny from Toyota. I think it's 2 pulses per rev if I remember right (very well be mistaken there)... just my 2 pennies for the jar...

Best,

Phil

[ZAMMY1]

on my '06 elise there is a speed signal used on the radio, the alpine that comes with the car. it's a square wave.
there's a thread about cruise control.
as i recall it's 400 kc@ 60mph.
check the thread.
good luck, sam

[robains]

Thanks for pointing me in the right direction, found several threads on cruise control and finding the "speed sensor" wire...

Best conclusion I can see is that on '06 Exige + there is a VSS signal on Pin #1 on the radio harness -- does this sound about right? Assume this is the same for 07 Exige S?

Also found info for using ABS signal, but if I have VSS already setup for me, I'll use that.

Some pics of my progress so far...

Tasks:
1. Install Pioneer AVIC-N4 + iPod unit + rear view camera.
2. Install JL Audio 5.25" front and rear speakers
3. Install Schroth ProFI II ASM Harness (driver & passenger)
4. Sector 111 CF center console
5. Custom shifter brace/support

I'm trying to document the entire process as I haven't seen a complete from start to finish thread/link yet including tools and notes. So far, I've managed to contain damage to just one broken plastic tab in the rear console tray.

Getting the seats out without taking of the roof was a challenge

Thanks all for the info, links, very helpful.

Rob

[charliex]

For future reference, if you had to run off the wheel speed sensors you can pick up a schmitt trigger and/or a frequency divider that will square out the signal and reduce the number of pulses to something the data logger will be able to use, normally they're settable to divide by 2,4,8 etc

depending on the frequency divider circuit it may not need a schmitt trigger input or it'll have one built in, i've seen a few of them floating around ebay.

[coolingmist]

Good thread. Just for anyone that wants to get a good speed sensor reading, this may be of help. you can even datalog it or convert it to a 0-5V output, activate devices based your speed, etc. It can read from 2 HZ to 20 KHZ. There are 2 frequency inputs (RPM, Speed, etc), 4 0-5V inputs, 1 EGT input, 1 programmable 0-5V output (based on 1 or 2 inputs) and 5 on/off ground outputs (programmable). Its a 7 channel datalogger, window switch, etc.

Those that want to read about it...

Smart Controller

This controller is only 3 inches by 3.5 inches and maybe 3/4 inch height.



I am in the process of taking my elise and putting in a carputer. I will be re-creating my own instrument cluster. I am still writing my custom software, here is a sneak peak. Please note that the gauge that says "FLOW" will actually be the speedometer. I will be integrating water temp, RPM, Air temp and a few other important goodies as well.

[robains]

That's a great find/link. I don't think I need it...I finally finished all the wiring last night and tested the unit (Pioneer AVIC-N4) for the 1st time. Rear camera was working nice when car was put in reverse.

I wasn't getting any GPS signal but I'm hoping that's because I have the car in my garage. Car wasn't moving so no speed sensor reading.

Found much great info on this site that helped me out a lot with hooking everything up. From Jim's 5.25 front speaker rings (which fit perfectly) for JL Audio to wiring harness diagram that was spot on for audio.

What I did find out is that Lotus wired the speakers up incorrectly going into the Alpine unit. The dash upper radio area is sealed -- what a pain to route the wires around the side.

Anyway, thanks for all the help folks have provided, much appreciated.

Rob.

[charliex]

I've got my carputer mounted in my exige, and by mounted i mean duct taped to the dash, and by duct taped to the dash, i mean fell off in the hot sun and sitting on the passenger seat.

been pretty happy with it so far, just need a proper mount to fit it.

[coolingmist]

Originally Posted by charliex

I've got my carputer mounted in my exige, and by mounted i mean duct taped to the dash, and by duct taped to the dash, i mean fell off in the hot sun and sitting on the passenger seat.

been pretty happy with it so far, just need a proper mount to fit it.

I plan something iddy biddy like this:

Logic Supply - Leaders in Mini-ITX & Small Form Factor Solutions

and a 7 inch motorized touch screen. I should be taping the speed sensor soon as I just got our device installed this weekend.

David

[charliex]

this is what i'm using currently
TS-7300 High-Security Linux FPGA Embedded Single Board Computer

[lotusfan2]

Charlie, do you have any links or pointers to a frequency divider that I could use on the wheel sensor signal (that goes to the ECU)? My Defi heads up display can just handle that signal, but I wonder if it'll get a bit more accurate if it is divided first.

[charliex]

I built one that goes down to 35Hz minimum its pretty straightfoward, i bought the end user parts this week and am currently testing it.

the 35Hz min sucks a bit, but if you divide it down to say 16 pulses per rotation which most hardware should deal with, the error isn't much, below that pulse rate i just cap it to zero.


soldering skills required would be fair, no surface mount, all through the hole. I put the pcb together in about 3 minutes, had someone who'd never soldered before do it in about 7, cost is about $40 in parts but its fully programmable and you can divide by real numbers.


I have the defi too.

[lotusfan2]

Thanks Charlie. I can handle the soldering part, easy. I found that I couldn't quite get the Defi unit to sync (using a GPS to measure my speed) at exactly 40 Mph, I had to sync it at like 36 mhp, pretending it was 40 Mph (or whatever the speed is the Defi manual suggests using). I'm hoping it can get a bit more reliable if I can just divide the signal by two.

[charliex]

its a 29 pulse per rev signal, so i wanted an accurate divider by floating point, if you're ok with a divide by two a simple counter will suffice, i'll dig out a circuit.

[lotusfan2]

Hmmm ok, didn't realize it was 29 pulse/rev. Dividing by 2 might not get me more accuracy then. How did you hook up the defi? Any accuracy issues?