S13 with RB25DET swap, how to get tacho/speedo working

[FreddieS]

Hi all, tried searching but couldnt find anything, the RB25DET wiring guide works spot on but says ask on SXOC how to find out about getting the tacho and speedo to work?

Any and all help appreciated

[alanjuggler]

you need a pull up 10Kohm resistor between IGN and SIG on the back of the clocks to get the S13 tacho to register the RB tach signal. if you're using normal S13 older clocks, with a mechanical odo (rather than the later 180 kouki style digital odo clocks) there's a potentiometer on the clocks that you can adjust to get the signal very close.

http://www.sxoc.com/vbb/showthread.p...unter-question

look at john bennett's posts.

In terms of the speedo, there's a few solutions, first is to use import clocks as below:

http://www.sxoc.com/vbb/showthread.p...B25-Speedo-Fix

I didn't - I wanted to retain the digital 180 clocks I have so used one of these:

http://www.picbits.co.uk/webshop/pro...p8t0csgpoecn21

mine needed a few modifications to it to get it working, if you go down this route, let me know and I can tell you what's needed - it's a bit involved for this post.

the other option that probably needs a bit less faff is the dakota digital SGI-5 box.

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

hope that helps.

[FreddieS]

Cheers dude really appreciate it.

Will tackle the tacho first, its got the earlier mechanical tacho as its a UK 200

[alanjuggler]

just seen your project thread, tis nice

the speedo was the last thing I finally got fixed - though mine was different again as I'm using an RB20 bell housing + SR20 box that was fitted to my old CA18 so I was using my original CA sensor, which didn't match my wiring or my speedo. loads of fun

[FreddieS]

Well. Got the tacho working. Low on funds to sort the speedo out at the moment but tacho was the main thing I wanted

For reference on mine it wasnt IGN SIG it was IGN TAM as per my photo below

Works nicely. Atleast ive got a visual indication of how its running




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[alanjuggler]

odd, john bennett isn't usually wrong, unless I've misread that thread and it's about something else glad it's working

[Fil]

My tacho works without the resistor, it just over-reads. I've never quite got round to fitting a resistor, but hopefully when I do it will bring it back into line.

[FreddieS]

Mine just sat there motionless. S14 and s15 will work out the box as they already have a pull up resistor. But they will be 33% out across the rev range


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[norfy]

on a s13 tacho there is an adjustment screw on the board/unit itself. iirc you wind it fully clockwise to get the correct rev reading, im pretty sure we didnt need to use the resistor, cant remember it was a while ago!

[FreddieS]

on a s13 tacho there is an adjustment screw on the board/unit itself. iirc you wind it fully clockwise to get the correct rev reading, im pretty sure we didnt need to use the resistor, cant remember it was a while ago!

You were right, but annoyingly you cant get to it without dissasembling the clocks.

Or, do what ive done, I dissasembled mine, marked where the pot is and wanted to see if there were any empty traces that I could punch thru with a drill so it can be adjusted with the clocks assembled.

4 screws to remove the tacho -



Oh hello, you naughty little potentiometer -



voila - 6mm drillbit thru the right place, bang on the money, easy to adjust now.



The speedometer has a similar thing, but it faces the top face of the clocks, you could easily desolder it and extend the wires for that one though.

[fikemoo]

sorry to be a noob but how do you know what clocks youve got?

[fikemoo]

trying to revive this post, i have followed said instructions, 10k resistor on the clocks and checked wiring, tach signal from ecu is going to tach of the F1 dash plug, i turn ignition and the rev counter bounces, start car but no revs at all

[FreddieS]

trying to revive this post, i have followed said instructions, 10k resistor on the clocks and checked wiring, tach signal from ecu is going to tach of the F1 dash plug, i turn ignition and the rev counter bounces, start car but no revs at all

Thats odd, would indicate that the ecu isnt outputting, are you going direct from pin 7 on the ecu to the clocks?