Jump to content
SAU Community

Speedo Calibration

chook

By chook,
in Four Door Family & Wagoneers

 Share

Recommended Posts

Sydneykid Grand Master

Sydneykid

Posted
Posted
Has anyone attempted to adjust their Series 2 electronic speedo ? mines about 10% out.

Is it adjusted through a trimpot in the instrument cluster or by changing the pinion gear in the sender ?

Why is it 10% out? Have you changed the tyre diameter?

D Cheers :P

  • 1 year later...
DaveB Mentor

DaveB

Posted
Posted

Just for prosperity's sake... my S2 is exactly 10% out too; reads 10km/h above what I'm doing (verified by GPS etc) at 60 and above. I have the standard tyre profile of 205/55/16 and brand new tyres. I'm going to fit the Jaycar speedo corrector kit - thanks for the verification that it works on S2 Chook! Which wire is it??? I would like to trace it without removing dash if at all possible...

chook Mentor

chook

Posted
  • Author
Posted
Just for prosperity's sake... my S2 is exactly 10% out too; reads 10km/h above what I'm doing (verified by GPS etc) at 60 and above. I have the standard tyre profile of 205/55/16 and brand new tyres. I'm going to fit the Jaycar speedo corrector kit - thanks for the verification that it works on S2 Chook! Which wire is it??? I would like to trace it without removing dash if at all possible...

i didnt have any trouble finding it, perhaps it is written on the back of the instrument cluster i think, and you can trace it to the plug and harness from there. If you still cant find it, send me a PM and ill pull cluster out and let you know.

Jaycar was bit confusing to set up, but havnt had to worry about it since, works great.

DaveB Mentor

DaveB

Posted
Posted (edited)
i think it is variable in 1% increments

Correct! Got mine today; two adjustments which can be used simultaneously, one varies by 1% per step, the other by 10% per step. I say 'varies' because it can be set to alter the speed UP or DOWN (ie. faster or slower). I agree with you Chook there are heaps of options...

I'll try to take some pics as I proceed. What I would like to do though, is install this in the passenger side kick panel, where I can splice it right into the correct wire near the ECU, rather than pull my dash apart and try to fit it in there. Can anybody think of any problems with this approach?

I have been looking at the pinouts of the R34 ECU (found here: R34 ECU pinouts) though and I can't seem to find a speedo output? Only "Vehicle speed sensor signal (Vehicle speed sensor 2) - pin 29" plus there is a "Output shaft rotation sensor signal (Vehicle speed sensor 1) - pin 58" however that is just for automatics (which mine is) and both those pins appear to be inputs, not the ECU output to the speedo?

Chook can you remember the colour code of the wire you had to interrupt to install your kit? I might be able to trace it at the back of the ECU and save some other people some dash-removing hassles...

Edited by DaveB
chook Mentor

chook

Posted
  • Author
Posted

1 Problem: I think the speed sensor goes to dash first, then from dash to ecu, (or perhaps 2 independant wires) so either way, you would have to intercept before dash to change your speedo, at ECU will not change speedo.

Ill check dash wire soon

danwatt Collaborator

danwatt

Posted
Posted
OK, 30min later, SPEED SIGNAL is BLACK with WHITE stripe, goes into the single row plug above the temp gauge on back of cluster. Just intercept it about 15cm back from cluster.

I checked some information about the V35/M35 speed signal and the signal is transmitted form the VDC/TCS/ABS control unit and received by the Combination meters and then re-transmitted by the Combination Meters (Dash Cluster) to the ECM (Engine Control) and the TCM (Transmission control) as well as the BCM (Body control). IF you were to correct the signal for the speedo you would have to do it before the speedo but who know how this will affect the operation of the ECM & TCM with a modified signal.

I dont know why the speed signal is out it doesnt make sense. Probably the easiest way to correct the signal is with larger diameter wheels (~3% greater diameter)

I can confirm the the M35 has the same problem.

DaveB Mentor

DaveB

Posted
Posted
OK, 30min later, SPEED SIGNAL is BLACK with WHITE stripe, goes into the single row plug above the temp gauge on back of cluster. Just intercept it about 15cm back from cluster.

Thanks Chook that's quick work! :laugh:

I checked some information about the V35/M35 speed signal and the signal is transmitted form the VDC/TCS/ABS control unit and received by the Combination meters and then re-transmitted by the Combination Meters (Dash Cluster) to the ECM (Engine Control) and the TCM (Transmission control) as well as the BCM (Body control). IF you were to correct the signal for the speedo you would have to do it before the speedo but who know how this will affect the operation of the ECM & TCM with a modified signal.

I dont know why the speed signal is out it doesnt make sense. Probably the easiest way to correct the signal is with larger diameter wheels (~3% greater diameter)

I can confirm the the M35 has the same problem.

interesting... your m35 is a generation later (V35/M35) than S2 Stagea (R34), but I wonder how much they changed it for consult II etc? I notice on autos the transmission speed sensor appears to be on a different pin ("Output shaft rotation sensor signal (Vehicle speed sensor 1) - pin 58"); but your info does explain why I can't find a speedo output on the ECU; there apparently isn't one! damn. If only it were that easy...

Correcting with oversized tyres isn't always easy, and is expensive; could the rule of thumb that "if the speedo guage can understand the speedo signal and display correctly, the gearbox, ECM, BCM etc. must be able to" apply? I hope so... i don't like the idea of playing around with all those systems. I wonder what difference it might have if they were calibrated at the factory on the original spec' (10% high) speed sensor output? Although I'm hoping it's just a pretty basic signal that the kit will reproduce accurately. I mean I guess most cars that this kit is designed to be used with (ie. those with digital speedos) would have these other modern systems as well? There is a warning in the instructions about airbag precautions, so they must surely know *something* about it... I hope... ;)

DaveB Mentor

DaveB

Posted
Posted

OK guys done some further investigation of the wiring diagrams Mike posted up for the R34, and it appears as though the only time the signal is passed on (well, I have to treat the combination meter as a 'black box' and assume the signal is actually modified in some way by it) by the combination meter is to the TCM (Traction Control Module), however this is apparrently only present on rear-wheel-drive models.

I would hazard a guess that this signal could be modified with some degree of safety, since if you modify it for one circuit (the combination meters) you modify it for all circuits thereafter (assuming that it is a simple signal which the speedo correction unit is able to reproduce accurately, and that you have it setup properly, however the way to guage this should be to simply adjust things until the speedo is working as before).

This speedo correction kit specifically says 'handles AC output for Nissan cars', or something similar, which I thought was interesting.

So thanks Chook, I might have a hunt for that wire (black with white stripe) at the ECU...

DaveB

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • The Bogan
      NC MX5

      By The Bogan · Posted

      Bit wet, but YUMMY
    • GTSBoy
      Pops when backing off throttle, rough-ish sound through rev range.

      By GTSBoy · Posted

      Keeping in mind that I am currently getting flat 10 L/100km on my RB25DET, which means >>500km/tank. I would test this car for vacuum leaks, check codes and AFM signal with NissDataScan as D says, check plugs, do a compression check while they are out.
    • Duncan
      Pops when backing off throttle, rough-ish sound through rev range.

      By Duncan · Posted

      It is hard to be specific half way across the world...but it *seems* like it might have a minor issue. Is the idle stable and does it rev smoothly? I would not expect any pops out of what I am assuming is a standard ECU, standard tune, standard exhaust. You can use Nissan Data Scan to find out exactly what is happening when it runs, the cable/software is reasonably affordable if you are not planning on changing the ECU (which hopefully you are not with an NA skyline) BTW your mileage may not be that far off, these are heavy old tech cars, and being NA might mean you use a heavy foot to keep up with traffic....
    • AdiR34
      Pops when backing off throttle, rough-ish sound through rev range.

      By AdiR34 · Posted

      Hey guys! Y'all are the masters so figured I'd check in on a few items here. - My engine sounds ever-so-slightly more raspy than the other NA RB25s I've listened to. It's barely noticeable but definitely a slightly different sound. - When I back off the throttle at high RPM, I will sometimes get a pop out of the exhaust, assuming this can be diagnosed as misfire. Some history on the car: - Had an exhaust leak in auction sheet but was claimed to be fixed by seller (bought from USA importer).  - Car's coil packs and sparks were replaced when it was sold to me, but unsure on what the gap is and whether the coil packs are correct.  - A prior mechanic had misdiagnosed a pilot or throwout bearing sound as LSPI/detonation. Had played with timing a bit, pops/raspy sound of engine just got worse. Got timing reset. - Had failed emissions a few times. First time went in as is, failed. Second time, replaced cat, still failed, running rich as hell. Third time replaced o2 sensor, passed. Car still smells gassy though. - Timing belt and valve cover gasket also replaced.  - Gas mileage is... low. about 350-400K per tank.  Any idea if I'm having any serious issues here or does this all sound like normal old NA RB stuff and I'm fine to drive it with the pops/slightly raspy engine? If it'll help, I can get drop a video of the sound of the engine.
    • Duncan
      Looking for a part number for this part here

      By Duncan · Posted

      So....to find any R chassis part number, get your VIN (will be something like ER33-xxxxxx for you) and go to: https://www.amayama.com/en/genuine-catalogs/nissan and enter it. From there you have access to a web version of Nissan's part system, FAST. It is a bit tricky to get used to, so maybe have a shot and post up what you think.  You can also search by general model but note in some cases your car might have different options so VIN is safest.  On diagram 211 I got 14075-75T16 for Connector, Water Hose If I search for part 14053‑21U10 that you posted, that is also a water hose but not the one bolted to the plenum and 14075‑04U00 is the fitting where the water hose goes into the block.
×
×
  • Create New...