Speedo Off

[Aelfwine]

2002 Recently purchased T4R. When I turned on my GPS I've noticed that the speedo is off by about 5km/h in average with the difference increasing when going faster and decreasing when slower. So If my gps shows me I'm going 95km/h I see 100km/h on my speedo. I've heard that gps is more precise with speed. My T4R is all stock for now.

 

[cencyc]

If you think the speedo is off, check the miles reported against the highway mile markers. The speedo/odo should be reporting revolutions of tires x circumference of the tire. GPS reports the time it takes for a signal to reach your gps unit from one (or more) satellites. The speed sensor should be more accurate than GPS, but it may be failing. I don't know if there are speedo shops in your area that can do calibrations, but I would check that.

On the other hand...since the original post "Speedo Off" sounded more like something Not Safe For Work....my real suggestion is to drive as fast as you can in front of many police officers and have them tell you how accurate your speedometer is.

 

[wc11]

5 kph or 3 mph for our US friends is not that bad.
+/- 5% I would think is within spec for an analogue gauge.
Although your stock, what is the wear on the tires. New vs old can account for 1-2%
At least you know your not speeding.

 

[afg10000]

Completely off topic but since y'all are Canada folks - Do you guys have VIN tags on all of your 4Runner's body pieces and parts? (assuming they were Canadian 4Runners at original purchase).

 

[Grenvilleter]

Just got a GPS a couple weeks ago and although I have not watched it closely, with brand new 265/70-16's , my speedo is out{reading fast) by 3.5-4kms @ 90-100 kms/hr.
As mentioned, I have not played enough to see if it's linear across the board or .if the amount of change is speed affected.

I guess I should believe the GPS but when I see where it wants to send me sometimes, I just don't trust it yet.

 

[snivilous]

Unless you are running stock tire diameter you will have a percentage correction in your speedometer. A good way to figure out how far you are off is to find a radar station and see what it displays your speed as if say you are going 20mph/kph and figure out the correction. It will be a linear increase with speed, so you will then know to add/subtract so much per 20mph/kph (or whatever speed).

 

[wc11]

Completely off topic but since y'all are Canada folks - Do you guys have VIN tags on all of your 4Runner's body pieces and parts? (assuming they were Canadian 4Runners at original purchase).

Don't think so or at least, not that I'm aware of.

 

[Aelfwine]

Do the abs speed sensors affect or take the reading for the speedo? I have a problem with my abs, haven't figured out what it is yet. Want to try and change the sensors but the damn things are pretty expensive...

 

[Aelfwine]

Could it be that one of the previous owners swapped lower gears in it? From what I researched could be the case. I plan on adding a 3" lift and 33"s. Would that even out my speedo?
What is the stock gear ratio on a 2002 sport anyway? Is there an easy way to check?

Thanks in advance!)

 

[wc11]

ABS has no bearing on the speedo. Neither will a lift.
Tire diameter will though.

You can try this chart for size & speed differences.

Tire Size Calculator

 

[kernel.panik]

Could it be that one of the previous owners swapped lower gears in it? From what I researched could be the case. I plan on adding a 3" lift and 33"s. Would that even out my speedo?
What is the stock gear ratio on a 2002 sport anyway? Is there an easy way to check?

Thanks in advance!)

there is a code on the VIN sticker in the driver's side door jamb and a reference chart on this forum somewhere...that will tell you what came stock.

You can also calculate it somewhat closely by jacking up the rear and turning the wheel one revolution and counting how many times the drive shaft turns. It would be hard to tell the difference between a 3.90 and a 4.10, but if you mark the driveshaft and housing, you can get a general idea.