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as im adding a speed sensor to my car, does the speed sensor signal need to be a 12v, 5v or ground signal?

is there 5v available at one of the terminals i can use to power the speed sensor?
maybe the tps supply at terminal 25?

brett_32i wrote: as im adding a speed sensor to my car, does the speed sensor signal need to be a 12v, 5v or ground signal?

I'm confused by this question.
Most obvious answer is that it depends on where you're goung to send that signal to.
But that might not be the answer that you were expecting...

brett_32i wrote:is there 5v available at one of the terminals i can use to power the speed sensor?
maybe the tps supply at terminal 25?

I think most Nissan ECU's have 5V at one of the pins.
Perhaps you might tell us whet car you're talking about

5 volts and looks like attached pic

well straight 5v is easy to do.

Any idea on what hz is required for say 100kmh?
then i can sort out a trigger to suit.

On what car?

rb30 in a vl commodore

brett_32i wrote:rb30 in a vl commodore

does a VL actually feed speed back to the ecu?
I was under the impression speed was only fed to the Autotrans comp.

Jaycar electronics have some interesting kits that may assist. speed sensor kit, or grab a performance car mag from them may have more info.

yes the VL/R31 ECUs use the speed sensor for fuel/cut tables for example

Also to determine if car > 20 km/h for clearing speedo DTC code and for determining if to clean the AFM hotwire after driving

Interesting that you say that Matt,
the VL I've been playing with is hopefully about to break into the 12s tomorrow night at WSID if all goes well and it hasn't had a speed sensor since we installed Nistune as we run a Fully modified Trimatic transmission. I also don't see any speed sensor DTC's with Nistune or with the stock ECU (led flashes) hence my assumtion it was only connected to the autotrans computer for kickdown calculations.

theres definately code throughout the ECU using the speed sensor

as for the DTC not sure on that. i noticed i only had aircond and neutral codes this morning on my RB30. i know that VLT RB30ET and CR31 RB30E DTC codes are different. perhaps CR31 only has speed sensor DTC?

I recently got my paws on a VL-NA factory manual commo.
No speed sensor, just the good ole cable from the box to the speedo.

apart from maybe a speed limit fuel cut or afm hotwire cleaning maybe holden figured out how to save costs and not add the electronics for speed sensing in their 1986 manual box commo's.

This is an ongoing argument I'm having with the dyno man atm.

he tell's me it doesn't need it, but Matt has proof it's in the code.
all I want to acheive is to see if the car runs differently when its connected and what maps if any are accessed differently.

Any code hackers are welcome to tell me when the speed input is required and it's impact so I can win this battle!!
If need be I'll spin the sensor on a ryobi drill to see what happens

Sorry for hijacking this one brett_32i, Did you get your speed input signal sorted?

your fuel/cut recover maps will not be accessed with no speedo input

apart from that I dont think speed will affect map accessing otherwise (RB30 ecus dont have that many maps and I've been checking most of them on the bench)

it may affect other 'constants' which are values the ECU uses for checking miscellanous stuff where I see speed being accessed otherwise.

speedo above 20 km/h i think clears the speed sensor DTC code (if there is one) and also to clean the AFM hotwire for 1 second when ignition is turned off. so thats 3 x things I can think of it uses it for

yes the speed sensor may not be on the trans, but there would be a speed input to the ECU going from the dash via circuitry inside the speedometer coming from the cable I would think

nah, still havent fitted it up yet. its sitting on the shelf ready to go.

The VL has the speed sensor in the dash cluster where the cable connects, both auto and manual have them