Jump to content
SAU Community

R33 GTR speed sensor problem?

Snara
 Share

Recommended Posts

Snara Collaborator

Snara

Posted
Posted

Hi

I have problem with speed in my car. In low speed's sometimes car don't see the speed both on cluster and aftermarket ECU . I changed gearbox and speed sensor in the gearbox and still have the same problem. What else i should check?

Link to comment
https://www.sau.com.au/forums/topic/473784-r33-gtr-speed-sensor-problem/
Share on other sites
GTSBoy Grand Master

GTSBoy

Posted
Posted

Change the speedo head.

Speed signal is +/- 1V sawtooth signal from sender to speedo head.  Speedo head electronics convert that to 0-5V squarewave for the ECU etc.  If there is no display or output at low speeds but it works at high speeds, then it's probably not a broken wire or loose connection.  it is some dodgy electronics.  You could take it to an instrument specialist.  You know, like we used to do back before the internet.

  • 1 year later...
CraigoGTR33 Newbie

CraigoGTR33

Posted
Posted

Great knowledge GTSBoy.  I have a similar problem with my car although I dont have a seperate set of dials.  Perhaps  you can help?

I measured voltage at pin 53 of the ECU (speed signal in from cluster) with the car sat still and it read 4.8V,  when it was moving this value did not change.  According to the service manual it should read 5V (within 1V) and then have dropped to 2.5V at 40kmh.  Would you think this is a problem with the speedo head or the speed sensor?  Any tips to find out more? Are there some connectors in the dash that can cause hassle?  It looks like faulty connector or sensor to me but i could be wrong!

 

GTSBoy Grand Master

GTSBoy

Posted
Posted

The voltage transmitted from the speedo head to the ECU is a 0-5v square wave. It is PWM, so the pulses change width according to speed. Trying to measure that properly with a DMM is not the best idea. An oscilloscope is the best bet.

Anyway, if you have a constant 5V there it suggests that the speedo head is not doing what it is supposed to. It's unlikely to be the sensor. If you connect a mutlimeter on AC volts setting to the sensor and drive, you should see a 0.6v to 1v sort of reading.

And obviously any of the connectors in the circuits could be janky.

  • Like 1
CraigoGTR33 Newbie

CraigoGTR33

Posted
Posted

Ok ill try that test and see what readings I am getting. 

Is there any information around the speedo head that you know of?  Ive got the white nismo cluster so it'd be a shame to take them out, better to fix them if possible.  I did have them out of the car a few years back and resoldered a few places which did the trick for a while but now the problem has returned!

 

CraigoGTR33 Newbie

CraigoGTR33

Posted
Posted

Ok to update the fix.. I took the instrument cluster out on the weekend and unscrewed the speedometer from the unit. On the back is a printed circuit board (PCB).  I saw a few videos on youtube for nissans around the mid to late 90s with problems similar to mine and they suggested simply resoldering all of the solder joints on that printed circuit board. 

I did exactly that and its worked so far!  No hicas fault lights and speed reading perfectly.  Power steering is working better and the engine seems to be running smoother but Im not sure if thats true or not! 

On the first test drive around the block the tacho also stopped working so i took that out and resoldered all that PCB as well. Hopefully I dont have to take them out again for a while. 

Thanks for your help GTS Boy - you were absolutely right that the clocks were at fault rather than the speed sensor.

CraigoGTR33 Newbie

CraigoGTR33

Posted
Posted

hahaha! yeah I must admit I wasnt expecting it to work, all the solder looked fine to me.  Goes to show that visual inspections dont really count when it comes to circuit boards... just resolder everything!

And now onto the next problem on the list.... ! #skylineownership

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

    • Dose Pipe Sutututu
      Dose's Sometimes DIY and Pay Someone Home & Boat Improvement Thread

      By Dose Pipe Sutututu · Posted

      Wife wanted basket things in the wardrobe in our temporary house. Thought about ripping our the wardrobe and fitting the entire IKEA set, but it's a temporary house and we want to move in a few years. So IKEA advertises this as a 50cm unit, however the actually basket and rails measure 46cm wide. Only issue was depth, IKEA stuff is quite deep, where as the builder special junk is super shallow at less than 40cm. Send it, chopped the rails, then offset the mounting holes, job done, happy wife, less shit scattered all over the bedroom. Did the same to the other side too. Also drove the Skyline shit box today, dropped off oil at Supercheap Auto. I didn't realise they only now take max 2x bottles per visit. I visited 2x Supercheap Autos.  
    • Kinkstaah
      Strange issue RB25DET wont start

      By Kinkstaah · Posted

      I've seen similar actually in my situation. You never know what tables are attempted to be used when the car thinks it's -99C or +200C. The fail state is not usually that extreme but you know what I mean - it was in my case though! This is where being able to read all the sensors is useful cause you see this stuff really quickly.
    • Kinkstaah
      First time Skyline owner

      By Kinkstaah · Posted

      The above is very important. However as long as you keep timing relatively low, it's plausible to make your own knock ears and plausible to learn to tune with a modern ECU that can do wideband O2 correction like a boost controller. I mean if you only have one viable road to even drive the car on, learning to tinker to this level may be worth doing given you can't do much else with the car...?
    • Kinkstaah
      Chris' Toyota Mark ii JZX110

      By Kinkstaah · Posted

      I find the fact that the rear plate has to be bent inwards at the rear not so bad: but the front is just awful: It's like come on. (these are my very old, now retired/turned in plates) TBH it is a lot of money to fix a minor issue, the fact I said "I'll never really spend the money on doing this" is why people ended up buying them as a gift for a 'car guy' who can be hard to shop for.. for car guy things.
    • GTSBoy
      Chris' Toyota Mark ii JZX110

      By GTSBoy · Posted

      I just bent the ends of my premo plates. It even went through Regency like that after the engine conversion and the inspector (a great bloke!) just squinted his eyes and said "I didn't see that". Plates, and how they look, are just something that have zero importance to me.
×
×
  • Create New...