calling all electricans!

[dannyboy77]

hi all hopefully a bit of development on the combimeter speedo problem! below is the FSM explaination for how the speedo works! from this can anyone electrically minded understand it and work out a way for the 4 pulse surf speed sensor to talk the lexus combimeter (who needs 20 pulses) and make the speedo show the correct speed rather than a 5th of speed you are going?

[Apache]

I'm pretty sure (though cant look at it now) that you can build a fairly simple logic circuit to output 5 pulses for a single trigger pulse, which is what you want.

I'll get back to you.

[BUSHWHACKER]

http://www.dakotadigital.com/index.c...rod&prd126.htm

[gary-r]

what bushy said - the dakota stuff is simple to wire in and it works.

[dannyboy77]

gary i guess by the way you are talking you have bought the dakota digital thing and have it installed? might have to get my aunty to buy it and send it over!

was just wondering if anyone here could wire something similar up on a circuit board?

[Albannach]

Isn't there a way of modifying the Lexus sender to accept the old Surf drive? I'm sure I saw it in one of the build threads on one of the Lexus forums.

[Ambobeer]

Building a simple logic circuit to convert 20 pulses to 5 might not be too difficult but the other way round is tricky.

Building a simple circuit to do this via a programmable micrchip is even easier and would cost pence. However sitting down and writing a program to this and then develop it to a working thing.....that's the tricky part.

[gary-r]

my whole dash is from dakota danny - easy to set up and its been trouble free.

i used the surf speed sensor on the transfer case for the speedo. thats linked back to the ecu and runs the motor and box shift.

it runs that way but it needs the lexus sensor for gearchange connected to work 100%. with the surf sensor only for some reason the ecu gives o2 fault codes and runs a bit rich.

[BUSHWHACKER]

Isn't there a way of modifying the Lexus sender to accept the old Surf drive? I'm sure I saw it in one of the build threads on one of the Lexus forums.

You're thinking of RMA on Yotatech, he converted an older cable drive sender as his was a pre-facelift 2nd gen.

[an1mal_69]

That Dakota stuff is nice..good call guys! Reasonable too with the current exchange rate!

I've not connected VSS1 and i'm getting the 42 code on the O/D light..obviously

What is the feed from VSS1 back to the ECU (via comb' meter) responsible for? Cruise control? Fuelling? I do have a stutter under hard acceleration..I'm wondering if it's caused by that missing signal?

Gary..does your Dakota speedo output the right signal to the ECU? How did you calculate the PPM?



Ok..just re-read danny's notes and answered my own questions.

20pulses upto the comb' meter to operate speedo, but then back to 1/5 (i.e. 4) to the ECU for engine, trans, steering, suspension & cruise control.

So..lol..is the 20pulses from VSS1 per shaft rotation? Or does it work out more with the gearing?

If it's per rotation..can't we just rob the signal from VSS2 to feed the ECU?

[gary-r]

the dakota unit is set up to accept most speed sensor pulse counts - its a simple 5 minute job to calibrate the whole thing (speedo and rev counter)
it has a feed for the ecu link on the unit - once calibrated it all works.

bushy uses no 2 to feed the ecu - no 1 is a tailshaft sensor(gear driven like a surf) - its not there due to the transfer box.

[an1mal_69]

found this too.. signal tweaker looks like a similar thing to the dakota..but cheaper

[Albannach]

found this too.. signal tweaker looks like a similar thing to the dakota..but cheaper

And unproven, for this application...

[Albannach]

You're thinking of RMA on Yotatech, he converted an older cable drive sender as his was a pre-facelift 2nd gen.

Yep, that's the one. I forgot it was a cable drive.

I thought you were on holiday?

[an1mal_69]

And unproven, for this application...

I found it on lexreme..where someone has used it for this application??