Speedo Wrong by 7mph - Page 2

SD1too · 26th May 2014, 11:29

Quote:

Originally Posted by HarryM1BYT

If that method involves adjusting the ABS pulse to the entire IPK, then it will cause the rest of the IPK to under read.

I don't know the answer to that I'm afraid. My post was simply to inform readers that there is a way to make the speedometer display more accurate.

Simon

HarryM1BYT · 26th May 2014, 11:37

Quote:

Originally Posted by SD1too

I don't know the answer to that I'm afraid. My post was simply to inform readers that there is a way to make the speedometer display more accurate.

Simon

The high reading analogue speedo, is another of those things which can be fixed by altering a byte in the IPK software - if only someone could work out which bytes do what.

The easy way, would be for a T4 guru to download the firmware from an ex-emergency service 75, which showed the correct speed and compare it to the standard firmware in the IPK.

The latest fix for the IPK shows the digital speed and very accurately too.

klarzy · 26th May 2014, 11:39

Quote:

Originally Posted by HarryM1BYT

The high reading analogue speedo, is another of those things which can be fixed by altering a byte in the IPK software - if only someone could work out which bytes do what.

The easy way, would be for a T4 guru to download the firmware from an ex-emergency service 75, which showed the correct speed and compare it to the standard firmware in the IPK.

The latest fix for the IPK shows the digital speed and very accurately too.

Should not need a T4 harry, the BMW scanners read the data file and can upload one...

Anon3 · 26th May 2014, 11:53

It's coming across as though this is a Rover 75 fault, but it actually isn't.

All analogue speedos over-read, as it used to be a legal requirement and if not now, is still a pretty much universal standard at least, I believe.

Think about it. If it was under-reading, you might be showing 39, whereas in reality you might be speeding in a 40mph zone, a situation that couldn't possibly be allowed.

And I have no reason to assume other than that GPS is incredibly accurate, especially at a constant speed, as has been said.

klarzy · 26th May 2014, 11:56

Quote:

Originally Posted by Anon3

It's coming across as though this is a Rover 75 fault, but it actually isn't.

All analogue speedos over-read, as it used to be a legal requirement and if not now, is still a pretty much universal standard at least, I believe.

Think about it. If it was under-reading, you might be showing 39, whereas in reality you might be speeding in a 40mph zone, a situation that couldn't possibly be allowed.

And I have no reason to assume other than that GPS is incredibly accurate, especially at a constant speed, as has been said.

of many new or nearly new hire cars I have driven while using my own tom tom I have found most to show 2 mph inder GPS reported speed @ 80 MPH

SD1too · 26th May 2014, 12:05

Quote:

Originally Posted by HarryM1BYT

The latest fix for the IPK shows the digital speed and very accurately too.

Call me cynical if you like, but my experience of software 'fixes' is that they either don't work at all, or your IPK isn't the right version, or the computer won't "talk to" your car, or you have to download some dodgy third party software before attempting the 'fix'. If you're lucky and it does work, you then find that a bug has been introduced or something else stops working!

Simon

Anon3 · 26th May 2014, 12:07

Quote:

Originally Posted by klarzy

of many new or nearly new hire cars I have driven while using my own tom tom I have found most to show 2 mph inder GPS reported speed @ 80 MPH

It definitely used to be illegal for a speedo to under-read, so I'm surprised at that, but don't doubt your word

I've never seen a speedo show lower than a GPS, which included a 2yo BMW 100 series

, but I don't drive in that many new cars, tbh.

pab · 26th May 2014, 12:15

Having had the speedo enabled in the message centre, the two readings are about 5mph different, the clock over reads. If I check the speed against my satnav the digital IPK speedo is the most correct.

klarzy · 26th May 2014, 12:17

Quote:

Originally Posted by pab

Having had the speedo enabled in the message centre, the two readings are about 5mph different, the clock over reads. If I check the speed against my satnav the digital IPK speedo is the most correct.

I would rate mine for accuracy as

1. digital +/- 1MPH
2 GPS +/- 2 MPH on flat straight road
3 Speedo needle -5% (was-9% before new IPK)

would be interesting to get reference against rolling road..

HarryM1BYT · 26th May 2014, 12:27

Quote:

Originally Posted by klarzy

Should not need a T4 harry, the BMW scanners read the data file and can upload one...

Yes, I know, but it seems to be the T4 Guru's who offer the service.

26th May 2014, 11:53	#14
Anon3 Posted a thing or two Rover 75 Join Date: Mar 2014 Location: Birmingham Posts: 1,394 Thanks: 199 Thanked 219 Times in 187 Posts	It's coming across as though this is a Rover 75 fault, but it actually isn't. All analogue speedos over-read, as it used to be a legal requirement and if not now, is still a pretty much universal standard at least, I believe. Think about it. If it was under-reading, you might be showing 39, whereas in reality you might be speeding in a 40mph zone, a situation that couldn't possibly be allowed. And I have no reason to assume other than that GPS is incredibly accurate, especially at a constant speed, as has been said. __________________ [SIGPIC][/SIGPIC] Villa, Stella, Balti. It's Brummie latin that means, er...... Vis tester available to local V6 owners

26th May 2014, 12:15	#18
pab Banned MG ZT V6 190+ Join Date: Sep 2008 Location: Leeds Posts: 33,223 Thanks: 41 Thanked 1,614 Times in 1,416 Posts	Having had the speedo enabled in the message centre, the two readings are about 5mph different, the clock over reads. If I check the speed against my satnav the digital IPK speedo is the most correct.