OK,Heres an update on my yellow peril cento.

After replacing lots of sensors and installing my own water temp gauge and other little detail jobs,the car failed its MOT on HC levels.

Now,thanks to the advice given on this forum and I really mean that,there,s been some cracking advice given here,I have checked rubber pipes,which are all OK.
I,ve checked to see if the cam belt has jumped,which also turned out to be OK.

Our issue is with the cold start device fitted to the side of the throttle body.

This is what I did.

I disconnected the battery.
Removed the electical plug from the device and removed the 2 torx type fittings holding it on.

I then sprayed a load of carby cleaner down the throttle body and into the hole left by the cold start device.

I checked the old one against the new one and the old one was at least 1/4 inch further out than the new one.
The original factory part is all black plastic,where the new one has a metal end to it.

I fitted the new component and fired the car up.
It ran fine but at a really high idle,like 1200/1500 rpm.
So,I killed the engine,then suddenly realised that I,d read on here a procedure for installing this part.
Once I,d put some slack into the throttle cable I fired up the engine but it started dong that BROOM...BROOOM...Broom.
Revving itself as if it was alive.

SO...(finally).
What did I do wrong?
I really want the new part on but after cleaning the old unit,it does tick over a little less lumpy.

Please supply me with the correct installation procedure and checks I can carry out to have a successful conclusion.
I,m so close with this car but every step forwards has me taking 2 backwards.

Thanks guys.

RALPH

SPi?

Cheers

SPD

Yup

SPi


RALPH

Are you sure you don't have an air leak somewhere?

Does the throttle spindle rest against its stop?

Cheers

SPD

No air leaks.
We,ve had a good look at all the hoses and pipes.
Got an oil leak I can,t find.
But I,ll get the engine degreased once I get an MOT
Then I,ll be able to see where thats coming from.
Rocker cover gasket replaced,so no issues there.

No,its just as soon as you put the new cold start part on to the
throttle body,it starts ok then settles down reving itself.
There was a post about this a couple of months ago but I can,t find it now.
I know theres a little dance you have to go thru before the ecu will accept it.

RALPH

I took a really good look around the old posts and found a post that suggested that I disconnect the battery.
Install and connect the new part.
Reconnect battery and turn ignition to prime but don,t start the engine.
Leave it for a couple of mins,then turn off ignition and leave for 20mins.
Then the car SHOULD start and run ok.

Sound good?
Or have I read the wrong procedure?

RALPH

Anyone?

RALPH

Still got a problem with this.
Can anyone point me in the right direction to sort this problem?

Once this is sorted,we can have a nice new MOT and another Cento on the road.

Recap.

Old cold start is over fuelling the car.
New cold start causes car to sit there revving itself.


Anyone?

RALPH

We,re talking about the Idle air control valve

IAC

RALPH

Just another update on the stiuation regarding my Cento.

Today,my friend Robin and I spent time sorting the front suspension,as I had a broken spring on the front nearside.
So,while we worked on that,we fitted the new IAC valve.
With the battery connected but ignition off.

After fitting a new front fog light and a new front strut,I turned on the ignition and fired up the car.
It revved itself to 3000rpm and sat there like that for a minute or two.
Then it went back to revving itself once up to temprature.
Then revved itself to 1500rpm,then back to revving itself.
So,we swaped the new for the old IAC and that was fine bar being a little lumpy at idle.

Our conclusion was that we are not following some sort of instalation procedure or we,ve been sold the wrong IAC.
There are no part numbers on it,so I,m going to phone JCS Fiat at Kegworth,who are very helpful,according to a Punto owning friend of mine.
I,ve never used them before,so I,ll let you know on that.
Meanwhile,Robin is going to run the car round to the MOT garage,that he is on good terms with and re test the emmisions,with the engine up to temprature.

I,ll let you know how it all goes.
But one things for sure.
We do not have any air leaks.
So near but so far...so far.

RALPH

Cold start is controlled via the water temp sensor (blue top).

The IAC valve allows air to bypass the closed butterfly thereby maintaining idle.

Try pulling the cone end of the IAC valve (use your old one) very gently, should move a few millimetres then refit but do not connect the power lead, theoretically the car should not idle. Now push home the connector and see what happens.

I,ve become very involved in these little valves and a new one from Fiat is a seriously stupid amount of money.
I saw on an American forum that to confirm correct function of the IAC to remove it and turn the ignition to prime but only for a second as the valve will push the plunger out.

Both the units I have work ok but the new one is a lot easier to move.

I,ll try your little trick and check the timing again,just to make sure everything is pukka.

My friend Robin,is going to warm the car up and get a quick check on the emissions with a hot engine.
The motor is running a lot better but still "hunting" a little.
I,m determined to get this thing running right tho.
Its a cracking little car when it runs well.

RALPH