Hi All,

Wife has a 2000 1.2 16v HSX, and I've had a lot of work done to it over the last couple of years..

However, the car has this reoccuring revving in the engine, I've had it with the main dealer, and he's fitted 5 (Yes five) potentiometers to it in fifteen months, but the problem remains. It drives her mad, as once the car start's 'from cold' it jumps up to 2500/3000 revs and takes a long while to come down...
I've brought it back to the dealer to have it reset and the following day the revving is back...

Not only that but until the revving stops the lights in the car flicker !!!!!

He now tells me it's the ECU, has this happened to anyone else out there, and if so how did you cure it..

If it does need a ECU, has anybody used the ECU Doctor? I've heard good things about him !

By potentiometer I assume you mean ICV ?
Did anyone measure the voltage on the battery terminals while the car is starting up and running in the high mode revs ?
Did you check-clean the main fuses under the bonnet ?


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Sven,

I would hope that the main dealer would have done this before he hit me with 'you may need a ecu'... But then again he's interested in making money,,,,,

I can check the voltage from the battery terminals myself when it is in high rev, can you give me a indication of what I should be looking out for?

The potentiometer, he's told me it the electronic valve that regulates the carburettor !

Do you think the ECU problem makes sence?

ECU - might be, but cant say for sure.

What you need is to measure the voltage during start up, must not go under 9,6Vand during the high revs stage it must be around 13V.
Also, did the mechanic use the same tipe and manufacturer of spark plugs ?


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Sven,

Thanks for getting back so quickly, I'll have to check the voltage back myself after work today, but the plugs are Fiat Original, put them in myself!

Might be the Engine Coolant Temp sensor. I had a similar problem and the ecu was telling the engine the temp was too cold and was trying to warm the engine up, therefore picking the revs up to about 2500rpm. Think the sensor was £27 and it sorted the problems straight away.

my car did this ,the whole time i had it..1st thing in the morning when cold,it would start up (absolute fine+on turn of key) to 2.5k..only lasted for around 15-20 s'.Then once warm,car would be fine.Never had a problem with it..
Isnt this normal for a car to warm up first?

Mike


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Nah it's not the coolant sensor, Fiat had it on their computer and the readouts were all fine, thay would have changed it, had it been the sensor by now....

As for the revving/warming up, I agree, all cars need to warm up, but the revs never drop below 1500 regardless of how long the car has been driven........

never drops below 1500 :s
Have you checked your air intake pipe,or you maf? Its fast idling for soem reason.Probably somethin simple.A split in the air intake can cause it to idle irratically..Or even a faulty maf..

Yep,

Checked by myself and the main dealer !

It doesn't come up on the diag, thats what fooled me! I had a local mechanic check it for me and when i had it plugged in it said it was fine.



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Hi Chris,

Nope ! took it off the car, cleaned it completly and checked it, no splits ot hirline cracks anywhere !

I just replied to your ECU post but feel I should mention a possible issue with the throttle body since I seem to remember this being a regular issue with some of the 1.2 engines. Look into having yours checked and possibly replaced.
Your dealer talking about carb's is BS since it is a fuel injected engine.

Hi,

The throttle body was changed by the dealer as well.....

I'm pulling out the last bit of hair I have on this one...

Tried a new alternator?

Bright, you didnt write the voltage.
Tom is getting on the same idea as me.


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Tom/Sven,

Sorry for not getting back to you sooner..

I took your advice and checked the output of the battery, and altenator at the same time, all were working 100% as they should..

I had a new Fiat alt put in approx eight months ago..

This problem is driving her mad, and I've been looking around local dealers to change the car, as it just seem to be a lemon, no matter how much money and time we throw at it...

It can't be fine if the lights flicker.

Tom,

Had it checked, along with the earths on the car....

The lights only flicker when the engine is in high revs, anything over 1000rpm after anything from 30 secs to four mins the engine returns to normal revs and the lighs stop flickering...

What was the voltage:
1. just battery, no engine runing ?
2. during starting, the starter motor turns ?
3. when the car is on idle ?
4. when the engine is on high revs ?



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