Hello again, i have more new problems to solve in my fiat seicento sporting 1.1 spi.

From when i have it when i start the engine i have around 2k - 1.5k idle rpm no matter cold or hot and drops in some secs around 1.1, 1.2 or stays on 1.5.

The fuel consumption is around 10liters/100kmh
28mpg

Any suggestions?

Allready install:
New oil
new spark plugs
new oil filter
new air filter
new thermostat
New coolant

Nothing?

Have you tried resetting the ecu so it goes and relearn the parameters?

Yes if you mean remove the battery cables and the idle sensor cable for some minutes.

It's one of those problems that is pretty impossible to diagnose without seeing/hearing it.

There's so many things it could be.

For a high idle, Idle control valve in the throttle body (worth taking throttle body off and cleaning that out), sticky throttle cable, a vacuum leak from any of the pipes to the TB or brake servo from the inlet manifold, poor seal to the throttle body/inlet joint, leaking inlet manifold gasket.

My main guess though would be the pipe running from the inlet manifold to the MAP sensor has a small split in it giving both a vacuum leak as well as throwing the MAP readings off and it chucking more fuel in to compensate. So check that pipe.

Hello thank you for your reply there is a split on the manifold and from there a big tube become smaller and then goes somewhere in the brake servo maybe, and a small one that goes to the sensor that is near the ecu "map" i think but this tube is installed without clamps and i remove it easily and i found grease in both ends. Any ideas?
I will take a picture.

The photos

This is the split from the manifold


The tube goes without claps on the map


And the other one goes somewhere in the brake system.

I make a test with the car on i remove the hose from the map and the rpm droped a little i put my finger in the hose and the car lowers more and if i hold my finger it should stop maybe.
Then when i put again the hose on map it start sound like i have aftermarket camshaft. I reinstall it and comes back to normal 1100-1200rpm.
When i press the throttle a little the rpms never come down to 1100 immediately stops to 1400-1500 and then comes down or stays there.

Try cleaning the idle control valve first. Remove the throttle body, and then the valve. Ensure it is clean, and the seat is in good condition.

If the problem is idle related, that is where I would start. The high idle would explain the fuel consumption also.

I have remove the idle sensor i clean it i reinstall it nothing changed. Maybe buy a new one? I spray the tubes that goes on the throttle body with carb cleaner to see if there is any rpm change to spot leaks but nothing. Anything else to check?

High idle is usually an air leak on the intake side. Check ALL pipes that go to the TB. Perhaps the gasket on the Intake mani to cylinder head could be leaking?