speedo issues ?

[dave05 Lurker Find all posts View Profile Close dave05]

I have a 1998 prado v6 3.4 automatic wagon

my issue is the speedo is saying im doing 100kmh but gps is saying around 105kmh

would it be more common for the speedo in the dash to be playing up or the sensor on the gearbox or could there be another reason
also I noted my speedo stoped at 40kmh and then suddenly dropped to zero after stopping at lights that has only happened a few times

car has been sitting unused for 5 or so years its just a project I have finally got on the rd

also the tyres are 245 70 size so my speedo should read a lower speed I assume

any help appreciated

Dave

[Guest Close Guest]

I don't know what the standard tyre size is for your 90 but I'm assuming 265/70R16? If it is, then your current 245/70R16 should cause the speedo to read faster than your GPS. Your situation is the opposite so it does point to a speedo problem.

[mjrandom Out of control poster! Find all posts View Profile Close mjrandom]

Different diff ratios to stock?

[dave05 Lurker Find all posts View Profile Close dave05]

Different diff ratios to stock?

not sure I have not changed them will have to check that out though

[Leethal Advanced Member Find all posts View Profile Close Leethal]

Hi Dave,

Is you Prado a RV6 as they have a different diff ratios and tyre sizes to the GXL and up models.
A bit more information will help.

Lee

[dave05 Lurker Find all posts View Profile Close dave05]

Hi Dave,

Is you Prado a RV6 as they have a different diff ratios and tyre sizes to the GXL and up models.
A bit more information will help.

Lee

its a GXL VZJ95R model but wheels are not original

[croozza Avid PP Poster! Find all posts View Profile Close croozza]

Its the tyre size then. change to 265 75 16 and all will be good again

[Shangus Find all posts View Profile Close Shangus]

With that increased speed reading with 245/70's wouldn't 75's just make it read even faster than your true speed.....

[mjrandom Out of control poster! Find all posts View Profile Close mjrandom]

Maybe 245/75 fitted instead of 265/70?

[croozza Avid PP Poster! Find all posts View Profile Close croozza]

With 265 75 16 on mine, the speedo is now spot on.
Doing this will give you the best starting point to find the problem.

[Guest Close Guest]

Going from 245/70 to 75 will slow the speedo reading even more.

[Shangus Find all posts View Profile Close Shangus]

Going from 245/70 to 75 will slow the speedo reading even more.

Dooh!! Thx AMTS that's what I meant.. Don't most of the earlier prados read faster on the speedo than you are actually doing so going up a tyre size makes the speedo accurate. See if you can find someone you can swap instrument clusters with to check if yours is faulty...

[dave05 Lurker Find all posts View Profile Close dave05]

I had the tyres balanced today to get rid of a vibration
I told him my problem he said if I went up to a larger tyre size the correct size I will actually be even worse of

might have to try a different cluster see if that sorts it out

[scottkz Senior Member Find all posts View Profile Close scottkz]

Is the speedo out by 5ks across the whole range? If it is just reposition the needle....

[dave05 Lurker Find all posts View Profile Close dave05]

Is the speedo out by 5ks across the whole range? If it is just reposition the needle....

you can just reposition the needle ?
hmmm very interesting is there a guide some where to do this ?

Dave