The BMW Car Club
of Great Britain & Ireland |
*** BMW Car Club GB website - see https://bmwcarclubgb.uk/ ***
*** Looking to buy or sell? ~ Checkout our BMW Car Club GB classifieds ***
|
E30 Speedometer Reading High |
Post Reply |
Author | |
MICK
Club Member Joined: 29 Mar 2007 Location: United Kingdom Status: Offline Points: 181 |
Post Options
Thanks(0)
Posted: 25 Feb 2016 at 12:49pm |
My 1984 E30 1.8i speedo is indicating 37 mph at a true 30 mph. Any ideas as to what might be the likely cause. The dial is steady reading with no fluctuations.
Edited by MICK - 25 Feb 2016 at 12:51pm |
|
Sponsored Links | |
RParkinson
Club Member Joined: 28 Nov 2012 Location: North Yorkshire Status: Offline Points: 183 |
Post Options
Thanks(0)
|
Tyres with smaller rolling radius than they should be, although 20% out is pretty excessive.
What wheels and tyres do you have on it?
|
|
2013 F06 M6 Gran Coupe
2003 E39 M5 1980 E26 |
|
NickDE
Region Chair North East Chairman Joined: 14 Mar 2015 Location: Newcastle Status: Offline Points: 1124 |
Post Options
Thanks(0)
|
Differential has been changed to one with the wrong ratio ?
Is the speedo wrong at all speeds ? Try comparing speedo speeds to GPS speeds.
|
|
Darkness gone, Tronic gone, Solo gone, DBA going, go Darknes2, go Frozen, go Black Pearl, go The Vibrator
|
|
MICK
Club Member Joined: 29 Mar 2007 Location: United Kingdom Status: Offline Points: 181 |
Post Options
Thanks(0)
|
Thanks for your replies.
I have owned the car since 1987 and the diff. has never been changed. The wheels and tyres are of original spec. Steel wheels with recommended tyre sizes fitted. Don't know when this started to occur. It's not my every day car so doesn't get used regularly.( E46 2.8 coupe is normal transport ) Have checked with Gps and the error seems to be constant across the range of speeds.
I started to think that it was the sensor on the diff. but that would probably make it read lower rather than higher I would guess. Maybe there is something I can do at the speedometer end ( like move the needle back ) |
|
RParkinson
Club Member Joined: 28 Nov 2012 Location: North Yorkshire Status: Offline Points: 183 |
Post Options
Thanks(0)
|
So is the error a fixed 7mph regardless of speed or is the error a percentage of the actual speed (about 23%)?
|
|
2013 F06 M6 Gran Coupe
2003 E39 M5 1980 E26 |
|
Lokoktentek
Forum Member Joined: 26 Feb 2016 Location: Slough Status: Offline Points: 15 |
Post Options
Thanks(0)
|
Hi,
Differential ratio has nothing to do with speedo reading. I wouldn't worry about the differnce. From my point of view it is normal. Don't worry :) |
|
Robert
Club Member Joined: 15 Aug 2006 Location: United Kingdom Status: Offline Points: 136 |
Post Options
Thanks(0)
|
The Speedo reading can be altered but it is an instrument cluster out jobby. There is a small white adjuster screw on the back of the instrument cluster. I wish I had fixed up mine last time I had the cluster out. Not an easy job but driving up and down the road a couple of hundred times to see if the adjustment is right is a bit of a hassle.
|
|
MICK
Club Member Joined: 29 Mar 2007 Location: United Kingdom Status: Offline Points: 181 |
Post Options
Thanks(0)
|
RPARKINSON. The error is constant right across the range of speeds that I have driven . ( up to about 65 mph )
Robert. I have had the speedo cluster out of the dashboard many years ago as there was a dry solder joint on one of the multi-plugs which stopped the speedo working and it is quite a fiddly job I agree . Found the fault by driving with the speedo lying on the dashboard and fiddling with it until it worked , then soldered the offending connector. Maybe that is the way forward,adjust it a little then try it. Thanks ,I didn't remember seeing an adjuster before. LOKOKTENTEC. I am just concerned that I am holding up the traffic by driving too slowly in 30 mph areas.
|
|
Lokoktentek
Forum Member Joined: 26 Feb 2016 Location: Slough Status: Offline Points: 15 |
Post Options
Thanks(0)
|
Yeah, you're right, it shouldn't be constant difference... Sorry i didn't read carefully :(
Maybe the easiest way is to borrow a cluster from someone and test it before doing any search... Of course if you can borrow it... |
|
MICK
Club Member Joined: 29 Mar 2007 Location: United Kingdom Status: Offline Points: 181 |
Post Options
Thanks(0)
|
Lokoktentec. I'll have a crack at it when I can devote some time to it. Thanks for your responses.
|
|
thechef
Forum Member Joined: 30 Nov 2014 Location: United Kingdom Status: Offline Points: 180 |
Post Options
Thanks(0)
|
I have same on my cars I have two E30's at the mo, a 318is and a 316i, both have 14" wheels with 195/65/14 tyres, and when I go through any speed traps - the one ones you get when you're coming into a town / village, and both my speedo's are 6/7 mph out, so speedo reading, 30mph, will get me a 23/24mph reading on the speed trap thing !!
I thought it would be something to do with tyre / wheel size, but I haven't changed the tyres sizes, although I did replace all 4 tyres on the i S, but they are same size as what was on it when I bought it !
|
|
MICK
Club Member Joined: 29 Mar 2007 Location: United Kingdom Status: Offline Points: 181 |
Post Options
Thanks(0)
|
Thanks for that reply. I suppose all those years of driving mine I didn't check the speedo for accuracy until I borrowed an GPS speedo which warns you when you exceed the speed limits.I'll have to look to see if there is any adjuster,if not I'll just live with it. Thanks again for your interest.
|
|
ZGreen
Club Member Joined: 25 Oct 2015 Location: Northants Status: Offline Points: 45 |
Post Options
Thanks(0)
|
Just a warning some of these road side speed indicators are not correct, I used to go through one regularly that showed my speed at 30 mph as being around 24-5 mph. But I went through a Mobile
Speed camera and did not panic as my speedo showed i was doing about 34mph I got done for doing 36mph, and like you I found cars backing up behind me and usually about 33 indicated mph seemed to cause less concern to those following. I went on a driver training option rather than get a fine and explained what happened but no comment was made as you might expect. |
|
ZGreen
Club Member Joined: 25 Oct 2015 Location: Northants Status: Offline Points: 45 |
Post Options
Thanks(0)
|
My speedo did fail once but it was the electronic connector plug on the diff that a little soldering put right.
Many speedometers read about 10% out. They say the Police allow for this. No comment. Edited by ZGreen - 01 Nov 2016 at 5:05pm |
|
MICK
Club Member Joined: 29 Mar 2007 Location: United Kingdom Status: Offline Points: 181 |
Post Options
Thanks(0)
|
Thanks for that information. I'll get under and have a look at it. in the weekend. Have temporarily marked the dial with the correct speed but it would be good to get it right. Thanks again.
|
|
RParkinson
Club Member Joined: 28 Nov 2012 Location: North Yorkshire Status: Offline Points: 183 |
Post Options
Thanks(0)
|
If it's a constant offset, maybe the needle on the dial has been removed at some point and not be put back in exactly the right place?
|
|
2013 F06 M6 Gran Coupe
2003 E39 M5 1980 E26 |
|
MICK
Club Member Joined: 29 Mar 2007 Location: United Kingdom Status: Offline Points: 181 |
Post Options
Thanks(0)
|
Thanks for your interest and advice. I've had the car since 1987. The dial has never been taken off or moved by me so if this has happened it was done before I had it. I would not attempt to remove the needle as I had a bad experience getting the needles off of my E46 2.8 litre. The guages would not work after being put back on so I must have wrecked the movements in the removal process. Cost me a new instrument cluster. Painful!!
|
|
Post Reply | |
Forum Jump | Forum Permissions You cannot post new topics in this forum You cannot reply to topics in this forum You cannot delete your posts in this forum You cannot edit your posts in this forum You cannot create polls in this forum You cannot vote in polls in this forum |