Odometer rising when stationary

stefanovich

Just noticed this the other day and wondered if it's normal. Car is idling in neutral and I can see it rising slowly.

dharn

Odometer measures miles/ km:(

corktina

do you mean rev counter?

YbFocus

I think you mean tachometer

corktina

assuming that is the case it could be due to the cooling fan or aircon cutting in

YbFocus

A friend had a undulating idle like that before and it was down to a nicked vacuum hose. Can be a number of things.

Massively annoying too for such a small thing!

BrensBenz

stefanovich wrote: »

Just noticed this the other day and wondered if it's normal. Car is idling in neutral and I can see it rising slowly.

Odometer "rising" while car is stopped? Is it a DeLorean?

One of the lads down the pub had the same problem with his odometer. Eventually, a Buddhist from NASA figured out that his odometer was possessed by those pesky Klingons and was actually measuring the Earth's passage through the space-time continuum. He had to use reverse gear a lot to remain in the present but other motorists weren't very happy about that. Kept waving at him but not with all of their fingers.

I'd sell it now or maybe get an exorcism done first.

colm_mcm

Think the OP has a corolla, in which case, the revs going up and down would be normal enough.

arleitiss

Quick question:
Is it normal for revs to bounce between 500-1000 RPM when you cold start car in a hot weather?

delly

arleitiss wrote: »

Quick question:
Is it normal for revs to bounce between 500-1000 RPM when you cold start car in a hot weather?

Not for the car you have, no.

arleitiss

delly wrote: »

Not for the car you have, no.

Damn :L

stefanovich

corktina wrote: »

do you mean rev counter?

No, I'm pretty sure I am talking about the odometer.

OSI wrote: »

Is it digital or analogue?

Analogue

YbFocus wrote: »

I think you mean tachometer

Nope. Odometer...

Listen, the bloody thing that measures how many miles you have travelled. The car is in neutral and the counter is incrementing slowly.

colm_mcm

What car is it?

corktina

you just KNOW who to call don't you?

dharn

Not possible the odometer is driven by the gearbox and can only move when the car is in gear moving, thats for mechanical, im sure some digital might take signal from somewhere else but still needs movement

stefanovich

corktina wrote: »

you just KNOW who to call don't you?

Ghostbusters?

colm_mcm wrote: »

What car is it?

Jap Corolla 2002

dharn wrote: »

Not possible the odometer is driven by the gearbox and can only move when the car is in gear moving, thats for mechanical, im sure some digital might take signal from somewhere else but still needs movement

Well it may be impossible but it's happening Maybe video proof is required...

I'm just worried the mileage is greater than it is supposed to be.

dharn

Well if you are putting up miles without moving im sure it is:D

Figerty

dharn wrote: »

Not possible the odometer is driven by the gearbox and can only move when the car is in gear moving, thats for mechanical, im sure some digital might take signal from somewhere else but still needs movement

No. Some cars are digital all the way. No cable to odometer. Had a Honda Civic that way. Output on the gearbox. If the sensor is faulty then it can be getting stray signals.

Or the car could be on blocks and you have the foot on the accelerator..

BrensBenz

stefanovich wrote: »

No, I'm pretty sure I am talking about the odometer.

Analogue

Nope. Odometer...

Listen, the bloody thing that measures how many miles you have travelled. The car is in neutral and the counter is incrementing slowly.

Figerty wrote: »

If the sensor is faulty then it can be getting stray signals.

Well, I'm convinced!

But until we have better information, we can only guess the cause. For instance, do you know for sure if the odometer is fed by a cable (a thin rod which rotates within a sheath) or by a sensor (electrical wire)?

These days, a sensor is more likely but where is it, i.e. where does it get its information from?

With the gears to neutral, does the odometer speed up when you increase engine revs? If yes, this might suggest the sensor is loose, vibrating in synch with engine revs and these vibrations are generating a false signal for the odometer. If no, we could be in resonant frequency territory, where the sensor is still loose but only vibrates at low / idling revs.

Or....it could still be dem fecquin' Klingons!

Truckermal

corktina wrote: »

you just KNOW who to call don't you?

Ferris Bueller???

Bogger77

On a 2002 Corolla, at least the UK one I had, the odometer and the speedo were fed by the same cable from the gearbox. The cable on mine snapped, and I lost both, but the rev counter still worked.

dharn

The above post unless of course its a joke makes no sense, rev counter fed by cable , cable broke, still worked

BrensBenz

Bogger77 wrote: »

On a 2002 Corolla, at least the UK one I had, the odometer and the speedo were fed by the same cable from the gearbox. The cable on mine snapped, and I lost both, but the rev counter still worked.

Mmmm! In the 80's, I had a UK spec Carina ll with the cable you describe. I'm surprised Toyota hadn't changed to sensors by 2002 but, I suppose, if it ain't broke.....etc.

Well, it looks like "something" in the gearbox is turning the OP's cable while in neutral. I know SFA about the internals of Toyota's gearboxes but I'd be tempted to undo the cable (if it's the same as the Carina, it's very accessible - passenger side, close to the bulkhead) and have a look at the rod end.

And I'd still like to know if, in neutral, the odometer moves more with increased revs.....?

Del2005

dharn wrote: »

The above post unless of course its a joke makes no sense, rev counter fed by cable , cable broke, still worked

Odometer and speddo feed from same cable, which broke, tacho is a different cable/sensor which didn't break.

wonski

Bogger77 wrote: »

On a 2002 Corolla, at least the UK one I had, the odometer and the speedo were fed by the same cable from the gearbox. The cable on mine snapped, and I lost both, but the rev counter still worked.

dharn wrote: »

The above post unless of course its a joke makes no sense, rev counter fed by cable , cable broke, still worked

Makes sense to me - rev counter fed by a separate cable / sensor.

dharn

Rev counter usually fed by ignition pulse,

dharn

Sorry misread post regarding cable , anyway the cable from the gearbox can only drive either
When the car is moving, drive taken off final drive

BrensBenz

Del2005 wrote: »

Odometer and speedo feed from same cable, which broke, tacho is a different cable/sensor which didn't break.

Correct! In fact, completely correct!

Bogger77

BrensBenz wrote: »

Correct! In fact, completely correct!

which was handy for me, cos about 15K miles after it broke, my car was totaled in a crash, but those 15k miles were missing from the clock so I got slightly more cash for my car :-)

stefanovich

BrensBenz wrote: »

And I'd still like to know if, in neutral, the odometer moves more with increased revs.....?

Attempted to test this yesterday and now it's not moving at all in neutral. I've only noticed it while stopped in traffic, next time I see it I'll rev.

Canis Lupus

Are you sure you're not mistaking your corrolla with a tractor and you're looking at engine hours instead :P

Bogger77

Canis Lupus wrote: »

Are you sure you're not mistaking your corrolla with a tractor and you're looking at engine hours instead :P

easy mistake with my own diesel Corolla

jetfiremuck

If it is doing it try unplugging alternator. You may have a faulty diode in the alternator

Anonamoose

Ghostbusters !!!!!!

JohnBoy26

If it's an e11 corolla, then its definitely a cable and not digital.

dougie-lampkin

The cable is plugged into the diff, where it's spun by the output. The faster you drive, the faster the cable spins. The cable drives the needle by way of a magnet spinning in a cup behind the speedo. The faster the magnet spins, the more the cup is spun. A spring stops the needle from simply going around at the same speed as the magnet, and instead the magnet "slips" inside the cup as it meets the resistance of the spring.

The odo, being digital, is not driven directly by the cable. Instead there's an analog to digital signal converter connected to the magnet in the speedo, that works exactly like the digital VSS in a newer car. This gives a signal to a microcontroller in the speedo unit, that can convert the speedo pulses into units, and make the odo reading increase. The cable can't be spinning while the car is stationary, as it's fed from the diff. So you must have an electrical problem, either with the "VSS" transducer, or the microcontroller that receives the "VSS" signal. It's possible that it's picking up on external interference, but pretty unlikely. I'd suggest you need a new speedo unit, or talk to someone who does speedo repairs, the components might be interchangeable.



tl;dr - You must be running low on speedo fluid, when did you last top it up?

stefanovich

It's a 2002 japanese import 3 door hatchback and the display is analogue not digital.