308 engine warm up idle

Hello All,

I have a question about my 83 Ferrari 308. Now that the temperature outside is getting colder around 40 degrees or so when i first start up my car in the morning it idles over 2000 rpm until it reaches normal operation temperature(when the light goes out on the dash)than it drops down to just under 1000 rpm. It doesnt do this all the time. It is quite annoying because with the car running at 2000 rpm it is loud. It seems the car is running hard with it not at normal safe temp. Why does it do this sometimes? What should i check for? Could it be a idle regulator or cold start valve? It did this a few times in the summer when it was 90 degrees outside also. But seems to be doing this more now that it is cold. Hope someone can help out! Thanks

Change the Thermal Time Switch in the Block behind the Oil Filter or at least check it.

The engine with a Working Thermal Time Switch should always idle Up when the temp drops below about 68 Degrees F.

How do you recommend I check the switch? If I unplug it what do I look for?

there are two bypass systems on the car, one is factory the other was to pass emmsisions. the reduntant one runs off the vacum temp switch in the overflow tank & thermal switch. if you look at the hoses entering the manifold on the passenger side you'll see the cold start injector and cold start bypass valve, you,ll also notice another bypass valve running off a selnoid, that one causes the extreme jump in idle. for mine i removed it, at the cold start bypass that runs off the CIS injection. works better and haven't had any issues. i'll see if i can post a diagram.

got it. part #35 is the additional bypass valve that causes the spike in rmps, that'll wear your rings real quick.

hey scott thanks fot the info. i will look at mine when i get home. so let me see if i have this straight. if i remove # 35 the car wont have the high rpm's at cold start up? if i remove # 35 what do i do with the small hose # 53 that comes off of it?

well since it's a bypass valve if you remove it. then you'll need to re-plumb the hoses to the WUR. a simple way is to just remove the vacum port from the solenoid so that it doesn't open, then plug that vaccum port to seal any leaks. i'll get some pics later of my engine to show you.

okay i figured a better way to explain, take hose #53 and disconnect from the valve #35. loop that hose (#53) back to un-used blank port on the solenoid valve (#52) that will effectivly dissable the bypass valve.

thanks for your time scott. ill let you know how i make out. i asume the car will take longer to warm up because it will be idling at a lower rpm?

Hi, Corey,

Welcome...I just thought I'd throw in on this....the higher RPM will warm the engine faster. On the older 308GTBs like mine they actually recommend a HIGHER RPM, more like 4,000!!!! I suspect that was to insure against plug fouling and such on the carb cars.

Yep, it scares the cows and the chickens!

It is far maore important in my mind to be sure you have a GOOD multi weight oil, and change this to allow for colder weather. Check your manual and see if this isn't the case...

I use Royal Purple exclusively. 20-50W here in Texas covers pretty much year round. That will let the oil get to the top end faster and guard against a camshaft seizing or something, which is why I think they have the RPM set high initially.

Watch them warm a race engine sometime.....they Whoop Whoop Whoop it to quickly pressurize the oiling system. I don't do that do a street engine but I routinely warm at about 3000RPM on a worn in motor, no worries. Gets the t-stat open quicker for water flow as well!

Hope this helps..