1.1 seicento 52 plate. Been stood around for a couple years. Has had new alt plus belt, new battery. Starts first time but when up to temp it cuts out. Will start again no probs but refuses to idle without a bit of throttle. What is wrong?

Clean or get new idle controll valve 10£ ebay and clean throtle body and intake mani (i didnt take mine off) and if still no change reset ecu

Best guess, gummed up idle air control.

Alternatively, fubar temp sensor.

Any eml?

Which temp sensor, where is it and any full explain as to how to replace please?

Green coded sensor (the only green coded sensor) on thermostat/coil pack end of inlet manifold. Replacements are one unit (the green sensor and the black plastic bit that mates to the inlet mani.

ive ordered an OBD2 diagnostic tool to see what that throws up. ill let you know what happens once its tested.

So I got,y OBD2 reader, plugged in, no codes.

What do people think then. Fubar temp sensor, lambda sensor or something else. I don't want to throw money at parts if I don't need them.

Please help

I'd remove the throttle body and clean it inside and out (carb cleaner). You might give it a service -- oil, oil filter, air filter. I'd at least replace the air filter at this point.

its an mpi, how do you remove throttle body please pics would help. I am pretty ok with diy mechanics, replaced dist, installed new brake pipes, bled brakes but not done throttle body before.

All it is is few bolts and unclip throttle cable dont mess with any throtle stop i used brake cleaner seemed to had done thetrick (get a rag in the inlets to if u can

So this is the whole inlet manifold/carb setup, the big black plastic thing? are there any pics of this process online and can you explain why this would cause my symptom please. To re-iterate: it starts fine and ticks over fine until it gets up to temp then it cuts out. It will start again and tick over but only with some throttle applied. It wont tick over on its own so to speak.

The IAC on the throttle body controls how much air by passes the throttle plate and gets into the engine. Obviously, some mechanism is necessary to do this when the throttle body is closed.

The engine will want rather more air, rather less fuel, once it has warmed up.

The other elephant in the corner is the coolant temp sensor.

BUT a really filthy or clogged air filter will have a similar effect.

The Seicento Technical Manual is in the Downloads section, free and gratis.

Right I am proper losing my rag with this little fiat. I have drained the coolant and undone the two 13 mm bolts securing the coolant temp sensor in place. It is loose but clearly held on with some strange Italian plastic clip thing which I will break if I carry on. Anyone any ideas?

Ok, got the bloody thing off, took some messing but realised it just pushes down from above after depressing a small clip inside.

Unscrewed the thermistor and conducted a test in a pan of water on the stove. Set multimeter to ohms (20k) at cold it read 2.0. As the water heated the reading went down, as you would expect so I guess the sensor is ok. I stopped the test when the reading was about 0.8, before the water started boiling.

Next stop is the thermostat, which I have a new one waiting to try. I shall test the old one when I get it out.

Have you actually cleaned the idle control valve/throttle body?

I dont think he has lol

Cento186 said:

Have you actually cleaned the idle control valve/throttle body?

Click to expand...

Thanks for keeping an eye on this thread. To keep you updated I have not cleaned the idle control valve yet. Mainly because I don't know where it is, how to remove or how to clean it. Please advise.

I can report that despite checking the function of the coolant temp sensor (ok) and now replacing the thermostat (which needed doing as the car has been sat for two years), the car still starts first turn, ticks over wonderfully for about 5/6 mins then just stalls. It starts again but only with throttle.

Please can someone treat me a bit daft and explain all about the idle control valve. In particular where it is, how to remove and how to clean/ what to look for if poss defective etc or even how to test if it is ok.

Once again many thanks.

It's in the throttle body (normally screwed into the side of it)

Best thing to go is remove the whole throttle body and clean it still on the body and check it is moving

The throttle bottle includes the whole intake manifold?

Right, throttle body off. Do the two black plastic things on the side screw out? On the underside I can see a black plastic thing that looks like it should maybe move backwards and forwards. It doesnt! Is it just a straight unscrew job, it's seems jammed tight.