Hi Folks, here is my story so far - I have drawn a blank so hope someone out there can help as I am slowly going crazy!!

 

Speedo stopped working and power steering got heavy.

removed clocks and re-soldered all connections on the speedo PCB

replaced clocks - still no joy

 

fitted secondhand set of clocks - still no joy

 

fitted new VSS - still no joy

 

so, now I have two sets of clocks and a spare VSS.

 

Checked old VSS with multimeter and it's OK

 

To eliminate this problem being the clocks, is there any way I can connect the VSS directly to the clocks whilst out of the car and if so what colour wires do I connect from the VSS to the speedo mylar sheet?

 

I've checked continuity between pin 53 on the ECU and the connector at the clocks and this seems all good.

 

Any advice on which colour wires I should be testing for continuity?

 

Failing that, anyone know of a good Auto electrician in the merseyside area, although would be prepared to travel to get this bugger fixed.

 

Any suggestions greatly appreciated.

 

Thanks, Trev

What's vss ?

Speed Sensor

So what reading you get on your vss ? 0-5v

Ok there is a real easy way to check out your speed sensor / speedo cluster in the car without leaving your driveway.

 

Speed sensor fail check : http://www.300zx.co.uk/forums/showthread.php?126425-Tech-tip-Speed-sensor&highlight=speed+sensor

 

Cluster removal : http://www.pexcom.com.au/z32cms/e107_plugins/content/content.php?content.321

 

 

1) Firstly jack up the rear of the car so both back wheels are about 1 inch off the floor and secure with a combination of axle stands and your trolley jack.

also clock the front wheels remember safety first.

 

2) Remove the dash to reveal the cluster, and turn the cluster around leaving the main three connector in. ( see removal link above )

 

3) Identify the yellow and green signal wire from the speed sensor there are two yellow and green cables, one is speed input signal one is speed output signal the input closest to the middle of the connector

 

4) Set your multi tester to the a voltage within the range of 12 volts, and set it to AC this is very important as the signal is in AC not DC

 

5) Connect one of the test meter leads to the earth of the car and touch the probe on the signal cable (yellow / green on loom) from the speed sensor

 

6) Start the engine and select first or drive and allow the wheels to turn slowly, and observe the meter reading

 

7) If a signal is present you will be seeing 1-3 volts, if you rev it a little you will get 3-5 volts

 

8) If the signal is present the speedo should be working, if not the speedo is suspect

 

9) If no signal is present, then it could the speed sensor or could be the cable,

 

The signal cable also is wired to the Consult plug, you could do the same test as above but use the probe in the Consult plug, if it does not work there its most likely a broken wire cable under the car, the speed sensor is unlikely to fail other than mechanically as set out in the above link and this can be seem physically.

 

If you have access to get under the car you can disconnect the speed sensor and check the cables out, if there is a break it is much faster to just rewire.

 

Most faults are in the cluster, if it is a jap spec car with a kph to mph converter fitted then that can be taken out of the circuit to confirm that is not the issue, as said most of the time the speedo cluster is at fault .

 

Jeff

 

This may be a shot in the dark, but recently has been discovered that some of the cheap (ebay/chinese) consult cables short the vss signal pin (in the consult-plug), resulting in a non working speedo/hicas/power-steering and other related issues caused by a missing speed signal

Thanks for all the suggestions folks. Haven't been using any consult cables so that's not the problem but good call anyway Lymon.

 

Rolandas, connected speed senor to my power drill and got variable voltage up to 3V - drill wouldn't go any faster - it needed charging!!

 

Jeff, cheers for the info, will be going through your step by step list at the weekend so will let you know how I get on.

 

After all the work I have had done to this, I can't believe a dodgy speedo has got me beat but I am determined to get it sorted.

 

Thanks again

Trev

Hi All, well just did the tests as Jeff suggested and at the speedo and check connection, I was getting variable voltage.

 

Tried this on both sets of clocks that I have. Reckon the speedo on the second set of clocks I bought must also have been broken.

 

Can these be fixed or is it off to get another set of clocks and hope for the best?

 

Cheers all

Trev

http://www.twinturbo.net/nissan/300zx/forums/main/view/1133844/More-gauge-cluster-repair-info.html

 

As a last resort, if you are out of options and don't want to buy a brandnew and very costly speedo from Nissan: this same guy on the US-forum ("DVDburn") can refurbish speedo's with all new components.

oops..forgot the link: http://www.twinturbo.net/nissan/300zx/forums/classified/view/172952/Gauge-gauge-cluster-pods-and-ECU-repair-new-price-options.html

Hi folks

Went through all the testing Jeff suggested and it pointed to it being two duff clusters.Managed to source a set locally off another member and all is good.

Just bad luck with the second cluster being duff.Thanks everyone for your help ,much appreciated.

Trev.