Bought my first 100 series - speedo is off by 20MPH at higher speeds. (1 Viewer)

[SMLE]

Hi folks,
Bought my first 100 series today and very happy with it.

One of the random things I need to look at is the speedo - at 64MPH today (shown on google maps on my phone), the car was showing 84MPH.

At slower speeds I don't recall it being as much but still 10MPH or more difference for speeds even at 30MPH.

I'm not super worried about that as it drives fine and don't believe that'll cause any issues with the odometer counting the miles etc but would be good to understand the issue.

I've seen people use plug in things to recalibrate it however I'm not sure if this would be suitable for such an exercise?

The instrument cluster had some LEDs repaired earlier this year by a previous owner but doubt that had any impact on it.

Thanks

 

[ScotyDosentKnow]

Hi folks,
Bought my first 100 series today and very happy with it.

One of the random things I need to look at is the speedo - at 64MPH today (shown on google maps on my phone), the car was showing 84MPH.

At slower speeds I don't recall it being as much but still 10MPH or more difference for speeds even at 30MPH.

I'm not super worried about that as it drives fine and don't believe that'll cause any issues with the odometer counting the miles etc but would be good to understand the issue.

I've seen people use plug in things to recalibrate it however I'm not sure if this would be suitable for such an exercise?

The instrument cluster had some LEDs repaired earlier this year by a previous owner but doubt that had any impact on it.

Thanks

What size tires are on it?

 

[hoser]

Any chance this is a JDM vehicle... and UK/MPH cluster was installed?

 

[SMLE]

Any chance this is a JDM vehicle... and UK/MPH cluster was installed?

Sadly not, it's not an import

 

[hoser]

Well, there are correction devices but I don't think any or the mainline ones can do 30%+ of correction. Even then, you would have to look into the electronic wiring diagrams because the speed sensors also affect transmission shift points and probably things like VSC, etc. I would suggest finding the root cause of this issue.

 

[SMLE]

Well, there are correction devices but I don't think any or the mainline ones can do 30%+ of correction. Even then, you would have to look into the electronic wiring diagrams because the speed sensors also affect transmission shift points and probably things like VSC, etc. I would suggest finding the root cause of this issue.

Could it be a faulty speed sensor? Thanks

 

[SMLE]

What size tires are on it?

275/60/R18

 

[daohaus]

275/60/R18

Based on the calculator that’s 31” and i think that’s factory.

 

[SMLE]

Based on the calculator that’s 31” and i think that’s factory.

Thanks

As an update to this thread, after that initial journey it's been absolutely fine.

I'm putting it down to water ingress from a leaking windscreen, which is going to be replaced in the next week or so (and is covered up in the mean time.

Thanks!

 

[SMLE]

I thought I'd revisit this as it's been a few months and I've been able to get a few thousand miles under my belt.

• The speed error (e.g. how much it reads out by) can vary during a journey
• Sometimes it's absolutely bang on, most of the time it's out about 8-10MPH, other times more
• Occassionally, I'll start the engine and the speedo and rev counter needles will sit on the bottom stop and just flicker for a few seconds and then come to life.

I'm planning to try and do some live data on techstream while I drive as that should hopefully give me a reading of what speed the sensors say I'm doing vs what the instrument cluster says.

I've seen a thread recently about swapping out components in the instrument cluster, however I'm not clear if this is possible for the speedo aspect and whether this would address the speeds being off/the occassional flickering I described above.

Any thoughts are appreciated.

Thanks

 

[J1000]

First thing that comes to mind is when the OP replaced the LEDs they may have bumped the speedometer clock spring. From my experience with other cars, that thing can be very sensitive to being knocked out of the correct position. Not sure if it's the same type on the 100 series as those other cars, though.

One thing to check is use an OBD device and see if the speed from the speed sensor is also way off, or if it reads correctly. If it reads correctly through the OBD then that would point to the speedometer itself being bumped.