Technical Erratically Revving 55 Punto!

[lesley3405]

My Punto 55 1995 has started to rev up and down both when the engine is cold and hot. Searching on the net and here I think it may be the ECU or Lamda sensor, my garage (not Fiat) think its also the ECU but can't fit it in to fix at the mo, they think its a big job?? They also suggested getting a 2nd hand unit from a scrappy!

I have asked for the car back as I only do a few miles per day and it runs ok for that. Anyway questions hopefully someone can help!

Will I do any harm to the car driving it while its like this, is it likely to just stop when Im miles away from anywhere?

Should I reset the ECU? Do I disconnect the battery for 3 days??

Is it an expensive job? I don't fancy getting a 2nd hand one. And do I need a dealer to do it?

Car is standard except for a 57i, had it from new, only problems were cambelt 12 months ago and its done 60k.

Really appreciate any help!!:I

 

[kebab]

too reset the ecu disconecting the batrry overnight would be more than enough however its very unlikly that it would solve anything.
but it is free
as for ecu's you can get exchange reconditioned ones with waranty from fiat which are quite reasonbly priced.
i dont think its the ecu myself, can i ask how high does it rev on its own (lots or a little)?


uno 1.0ie RAAAWW!

 

[dave]

how old is the 57i it may need cleaning or may have come loose.

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[lesley3405]

Thanks for the replies!
The kit is about 4 years old, I have to be honest and say its not in the best condition and would benefit from a clean.
The revs can go really high (no idea on rpm though) but the tendancy is for the revs to go high for 2 secs then back to normal for 2 secs and then back up, this goes on and on.
I really hope its not the ECU!I just thought other things would go wrong with it if it was.
Thanks
Lesley

 

[kebab]

the high reving kinda rules out lambda in my opinion, the coolant temp senor might be worth trying.
If you disconect it the ecu will assume a fixed temperature which could rule it out if it still revs.
the sensor is on the back of the inlet manifold, 2 wire sensor.
(gearbox end of the engine)
its worth a try because its free

uno 1.0ie RAAAWW!

 

[thefishdude]

you should also deffintly clean your 57i filter or gets clogged up

2001 Punto sporting in sprint blue with matching Mr Bump air freshner all together now mmmmmmm

 

[G.Q]

cleaner fuel lines maybe? efi fuel injector cleaner

 

[smokeme]

How's the throttle response, it could be the tps sensor

 

[T14086]

Disconnect ECU first for 10 mins as mentioned by many posters already,wont do any harm & often cures problems like this (same with fords/vauxhalls etc) and got to start somewhere & so start with cheapest options!

 

[kebab]

er nice necro-post, im pretty sure he would of fixed it by now.

 

[T14086]

ROFL Ooops may 2004....yeah slightly out of date wasn't I....just like my dress sense

 

[peterthebiker]

my punto started revving up to 1500, then down, then sometimes to 3 or 4 thousand. It was only two frayed wires going into the fuel injector,pulling them through the grommet and insulating them solved the problem!!
ps it's m reg, only 54000 miles