At the end of the cam cover to manifold hose is a small plastic valve ... spring loaded and prone to several things:

1) it can get gummed up over time as oil leaves the crankcase and is sucked into the intake (part of emissions system)
2) the outer case of said valve gets brittle and the clips on the end depart for a better life and then air gets in
3) the innards are lost when you swap over the intake


Also if you have FiatEcuScan or MES as it now known (or a working copy of AlfaDiag), have you tried resetting the throttle and then the 30-second trick?

 

Had exactly this problem on my Fiat Coupe 20V VIS (just about all of them had this issue), it's got the same set up as the TS. The post from Gazza above has given you the answer, quick check to do when it is idling too high is remove the oil filler cap and see if the idle drops to the right RPM.

The fix is to remove the spring that sits on the poppet valve (see picture above) and leave it out, then put everything back together and the car will run correctly. You'll need to reset ECU and do the throttle learning as well afterwards but it's a pretty easy problem to fix.

 

Gents,

Thank you for showing an interest, just out of curiosity, do either of you know how this causes the higher idle?

I will have a look at it tonight. My concern is how to test it? if i open the oil filler cap, then that will let in air after the MAF at the Intake breather.

I did find that my downpipe is like swiss cheese at the moment where an exhaust clamp at the subframe has been rubbing and has left several small holes in the exhaust.

So i have a new pipe to fit, plus a new lambda sensor.

I did try to seal the exhaust system, just to prove the concept that it was an exhaust leak, but the high idle returned after a few hours of driving.


Yes i did also try the throttle/self adapt resets too.

 

Also, how do you remove the breather from the intake manifold? does it clip on? does it just slide/pull off?

I damaged on intake manifold so i swapped it with a 2nd hand one from a friend, the replacement still had this breather fitted. I might pull my damaged old intake manifold apart to remove this part, then fit it to my current intake as it works.

I have all the parts so should be able to quickly swap them out tonight!

thanks again gents! it is giving me hope! haha

 

It's really easy to take off, referring to the photo in Gazza's post:

• Using a small electrical screwdriver (or similar) carefully insert it in the small recess in the top part of the breather (just by the O ring) in the photo
• With a small bit of pressure lever the top part off the lower part (doesn't need much), the top part will come off easily.
• Remove the PCV valve and spring from inside
• Remove the spring
• Clean up PCV valve (poppet)
• Clean up hose attached to top and anything else you can get to.
• Replace valve (poppet), do not reattach spring
• Replace top, just needs a small bit of pressure to reattach it.

The valve is part of the Positive Crankcase Ventilation, a quick google will reveal all but basically it allows the gases that blow by the piston rings to vent in a controlled manner. It's all part of the engine wearing, I wouldn't worry unduly and get an engine rebuild though!!

If it makes you feel better I went down the same path as you, looking for leaks, putting on a new Lambda and MAF. Frustrating as a really easy issue to rectify, hopefully the fix above will sort your problem.

 

Right so before I replaced the PCV, I thought I would try something. I disconnected the hose at the cam cover and put a large bolt in the pipe with a jubilee clip on to make sure it was tight. Then a Nitrile glove, wrapped over a few times, jubilee cliped to the top of the cam cover. This meant that the PCV path was blocked and air tight.

Idles perfectly.

Says to me that there is too much air coming from the breather into the intake.

So i pulled the PCV off, I had a spare so i was going to fit that... i dropped the replacement spring, it went through the bonnet catch hole into the steel box section, never to be seen again!

Anyway my spare housing and o-ring seemed in better condition than the one i took off. So I cleaned it all up, reused the old poppet and spring, put it all back together.

Removed the glove and bolt, i.e. back to OE spec. And it still idles too high.

Refitting the Bolt and glove, i.e. blocking the breather, then makes the engine run correctly.

So either:

1) the spring has gone soft and is letting in too much air
2) my crank case pressure is too high.

Now regarding the 2nd option, I do tend to run with a bit more oil than i should (I check the oil when cold rather than hot to make sure that upon starting, it always has some oil) but this does mean that once warm, the oil level would be deemed "high".

Perhaps this excess oil is causing my crank to become too pressurised.

Ill drain some oil out tonight and see if that makes a difference. but for now, driving around with the 1 breather (cam cover to intake hose before the throttle body) may just get me by!

 

The fix is NOT to refit the spring when refitting the PCV poppet valve.

 

Why would you Not fit the spring? Its there for a reason surely!

 

Try the 90 second reset .. turn the ignition on for 90 secs but don't touch throttle, turn off for 90 secs. Now start car without touching throttle pedal and leave it to idle for a few mins .. the idle should drop after a min or so. If it doesn't you may need to reset the idle actuator with MES as this is now out of sync with the ECU. You will have to repeat the 90-sec reset. Pulling the throttle cable causes this too.

This caught me out a few years ago and I tried different throttle bodies, changed the idle actuator motor and eventually found that missing PCV valve (or at least the innards!)

And put the spring in the PCV .. it doesn't work properly without it. The spring pushes the valve closed.

The reason it ides high is as the crankcase pressure increases as you rev higher, the valve opens and lets the crankcases directly into the intake rather than passing it through the throttle butterfly. The other hose is for low speed crank pressure which goes to the inlet hose before the throttle body (and gums it up!)

It's part of the emissions system ..

 

Gazza That was my understanding too, after reading your page about the idle saga, and finding the poppet had been completely removed and had rough running, i was very surprised when Wal said to remove the spring, and without that it would inevitably end up in a situation where the poppet gets stuck and then shows similar symptoms as to having no poppet at all. Without the spring there is no control over its position.

Ill have another crack at it tonight.

 

any news on that? Did you manage to have it fixed?
My 2.0 TS suffers too at the moment