348 ts idle issue

After full warm up coolant temp should be consistently above 84ºC. Cold coolant temp, and even colder coolant temp while drive = bad thermostat. Here is the DIY t-stat removal http://www.ferrarichat.com/forum/technical-q/385608-348-thermostat-removal.html

As for the hunting at idle try this:

1) Disconnect the battery, let car sit overnight.
Reconnect battery in the morning when engine is cold
Let engine idle with all accessories turns off, do not touch throttle
what at least 15 minutes, or until fans come on
take car for 30 minute drive

2) Check the resistance of the throttle position sensors http://www.ferrarichat.com/forum/technical-q/453969-348-throttle-position-sensor-adjustment.html

3) Check all vacuum lines to make sure they are not leaking and properly attached

4) Clean out idle air control valves http://www.ferrarichat.com/forum/348-355-sponsored-bradan/376281-idle-control-valve-fix-sort.html

5) Check resistant of Mass Air flow sensors http://www.ferrarichat.com/forum/technical-q/20378-mass-air-flow-sensor-adjustment.html and http://www.ferrarichat.com/forum/348-355-sponsored-bradan/167575-348-maf-adjustment.html#post137074650

6) Check crank position sensors http://www.ferrarichat.com/forum/348-355-sponsored-bradan/236698-kia-fiat-crank-position-sensors-cps-work-348-a.html

7) check coolant temp sensors

 

It's possible that the thermostat is stuck open, causing the engine to run cooler than it should. But that may not be the cause of the idle issue. You didn't mention trouble codes-- are there any stored on either ECU?

I would tend to suspect plugs and/or plug wires first if there aren't any codes stored, but there are a number of potential causes.

 

If what Ernie and Mike have suggested do not work, check the fuel pressure regulators as well (it comes in a pair). I had a hunting issue at idle as well and tried everything, including what Ernie has suggested. To no avail.

Finally, my mechanic found the issue to be a leaking fuel pressure regulator. Changed them and the hunting problem went away. One more thing, the original Ferrari fuel pressure regulators are very expensive. It's a standard part that is used in other cars. Got it for about USD 70-80. The original part costs about 3-4 times more.

 

In addition to what was mentioned above ..... verify all vacuum hoses are in good shape and in place. Also check your throttle adjustments are in sync.

 

How fast is the idle speed?

The reason for asking is because when it comes to the idle speed, even once fully warmed up these cars idle faster than most everyday cars.

My BMW once fully warmed up idles @ 600rpm, My 348 on the other hand, under the same conditions, idles @ 1050rpm as standard (Ferrari specifies the warm idle to be 950rpm + or - 100rpm).

When I first got the car, it seemed as though the Idle speed was incorrect as the engine seemed to be racing at idle, but then I found out it was as it should be and I've got used to it (saying that though, when I'm sat stationary in traffic in the middle of a city with pedestrians around, I do still become a bit self-aware of the fast idle speed!)

 

Mine idles right around 950

 

As other threads on idle speeds have shown, they vary all over the place between 850~1100rpm - There doesn't seem to be a single standard setting for all cars, in the way that you tend to find on other mainstream cars such as BMW's.

When you're not used to the cars, they do sound as if the idle has been set too fast, but it is normal.

The OP's car might have an even higher idle than normal due to having an issue (amongst others), but I just thought it would be a good idea to make them aware that these cars do idle comparatively high normally.

(It would be interesting to hear just how high the OP's car is idling).

 

I have found that it is important to keep the throttle bodies balanced. You can have one throttle body with the bypass/bleed screw open more than the other. That can cause the idle to hunt because one side will want to idle lower/higher than the other. Especially since the f119 is run with two separate ECUs.

 

How old are the o2 sensors? Do they have the external ground wire?

 

Was the old fuel flushed out and injectors cleaned yet? ....glad to hear this car will be back on the road where it belongs ...

 

Yes - @ 1000 rpm is just about spot on!

(As I have posted, when I first had My 348 the cold idle seemed too high, and like you I had concerns, but on checking on the internet and contacting The Ferrari Centre who sold Me the car, I was reassured that it was correct and normal).

 

If laid up that long get all traces of old fuel out and fit a new pair of fuel filters soonest. Also, long shot but worth thinking about, rubber components in the fuel tank breaking down, so fine debris. Plus one or more injectors gummed up?

 

Just wanted to chime in and say thanks to Ernie. This thread helped me find that it was the throttle position sensor and now it’s back to golden.