Speedometer issue

[hellomoto]

Here’s an interesting one. My speedo has taken on a life of its own. It fluctuates sometimes working and sometimes not. Does anyone know if it’s a mechanical system or an electrical one? I’ve been told if it’s an electrical system it may be the sender unit, usually located on the gearbox. Anyone know if this is the case and where the unit may be located?

Appreciated

[Riff Raff]

Sounds like a mechanical speedometer "cable" symptom (on "old school" cars), and that the speedometer cable needs replacement. I'm not totally exactly sure what type of speedometer input (electrical or cable) our VX's have. Perhaps someone more familiar than me will chime in with a better prognosis. Does your VX have a lot of miles on it??? Typically, only high mileage vehicles will develop this symptom over time/miles. Let us know what you eventually find out.

[deermagnet]

Our speedo is all electrical and it gets the signal from the Vehicle Speed Sensor.

http://www.drivehq.com/file/df.aspx/publish/mgpa/vx/vx8/vss2.gif
http://www.drivehq.com/file/df.aspx/publish/mgpa/vx/vx8/vss.gif

Mark

[Y33TREKker]

Our speedo input is provided by a solid-state "Vehicle Speed Sensor" located on the rear of the transfer case (passenger side, lower electrical plug near the drive shaft).

You might try just unplugging it's connector from the transfer case, cleaning all the contacts, applying some dielectric grease, then plugging it back in. Maybe it just got wet or a little rusty and you're experiencing signal loss.

[hellomoto]

Fixed it. Thanks everyone. The contacts on the sensor were just a little dirty. All clean and all good now.
Now for this one!!!! Sometimes, when warm (never cold), when I start her up she revs up to between 2,500 - 3,000 rpm, then very very slowly returns to about 800 rpm. Anyone?

[technocoy]

Could be the MAF, EGR, or Idle Air control. I'd work my way back from Idle Air Control, EGR, MAF.

After having my EGR replaced and getting ready to do the MAF (bit expensive) my mechanic (former isuzu tech) thought to check the idle air control. That was it. I think it's was 150 bucks or less to replace.

[hellomoto]

Ok so I’ve checked and cleaned everything on the list (MAF, EGR, IAC, etc). So now I’ll wait and see if she does it again, or not. It only ever happened occasionally and never showed an error code.
I think she just likes to be the center of attention and is only happy with my undivided attention, much like my wife really.

[circmand]

check your mats arent sliding up and hitting the throttle from below

[hellomoto]

Checked that one first thanks. I know it's an easy on to over look

[Y33TREKker]

Do you have aftermarket additions to your gas and brake pedals? If you do and they are wider than stock, it can be easy for your foot to be hitting the gas when you are touching the brake and not realize it.

[hellomoto]

No, all standard. She's been good for now and it only ever happened the few times.
It still drove good, just a high idle