Help needed - rpm meter gone crazy

[manchild]

The car is Peugeot 206 1.4 but I don't think that is very important.

On IDLE it started showing all of the sudden 5000 rpm. As revs rise it rises above 5000 rpm reaching end of the red zone.

The car was washed one day before it happened so I suspect that perhaps water has penetrated some electrical circuit. I'm not sure does it read out rpm via ignition coil like on older cars or via engine computer?

Any ideas?

Thanks in advance.

[majicmeow]

What year of 206? Petrol or Diesel?

[joseff]

Consider yourself lucky. My old 306 used to actually gas itself to 4000rpm, with foot off the pedal. Fix: replacement ECU. Ouch.

[manchild]

What year of 206? Petrol or Diesel?

1999, Petrol 1.4

Consider yourself lucky. My old 306 used to actually gas itself to 4000rpm, with foot off the pedal. Fix: replacement ECU. Ouch.

But engine works fine so replacing ECU just to fix rpm meter isn't really necessary, right?

[joseff]

Nah, just relating a totally unrelated experience where the engine went crazy instead of just the tach

[HKS]

Hey your tacho might have got a bit excited if you wuld have taken it for a race.

I can imagine a normal car idling at 5000rpm

The resistor or the pot (or if any other device which converts rpm speed into resistance) might have become faulty coz of washing.

Check it and replace it. if ts a Pot it would be cheaply available or if its a complicated sensor then I cannot comment on it.

Cheers

PS:I would love to love a car which actually has an idling rpm of 5000, without me paying for the fuel expense.

[Ted68]

Unless you regularly pull off redline shifts and NEED a tach, reach up under the dash and unplug it. Wait a few days for it to dry out, plug it back in, if it's still wacky, unplug and forget. Tachometers are fairly useless on roadcars anyway.