The smell of unburned fuel during warmup and greyish smoke when warm when hitting the throttle. Yep this lady is clearly drinking too much! We all know that smoking and drinking is not good for your health, that applies to cars as well 
Most workshops tend to fiddle around with the mixture setting to correct it. “Correct it” are in my opinion not the correct words. It is camouflaging the real problem in most situations.
The first thing I do is pulling the plugs to read them. For my drinking lady they looked like the first photo.
Knowing I deal with an old car the mixture setting on the CIS is most likely not the problem since Ferrari already put it on the correct mix and somewhere a long a long the way something changed, that is, you could have guessed.. ..rubber..! All kind of small micro vacuum leaks influence the drinking behavior of your engine.
One way is to detect them is with brake cleaner and a more expensive way is to do a smoke test. I am neither fan of these if you are dealing with a car that is over 25 years of age, perhaps break cleaner if you know what you are doing without inflaming yourself so be careful with using that method.
A smoke test is not cheap and if you read out the spark plugs you most likely already have your answer anyway. I’m in favor to spend the money on new rubber, which in the short run will save you money.
So on which rubbers did I spend money to get the lady off her drinking problem.
1. All the vacuum lines that go to and from your throttle house, check valve, and airhouse. I call this small money. Not more then 30 USD (20 euro) including clamps.
2. This one is a but more challenging. The plenums that are between the air house and the intake manifolds. A bit more work and the plenums are each 20 USD (15 euro) you have 4.
3. Since you have the lot of anyway you better continue to replace the rubber o-rings of the injectors as they have been sitting there when the Mondial got it’s first owner. This is small money too, but you will need to take off the intake manifolds thus replacing the intake manifolds as well, which are around 30 USD (20 euro) a piece and you need 2.
4. Replace all your injectors with new ones. They cost 40 USD (25 euro) a piece and testing them for this money does not make a lot of sense.
Looking back what I have done and the result and findings the lady now runs properly and is not drinking anymore. Looking at the spark plugs now they look healthy and that without touching the mixture settings at all. Like I said it was already set correctly when it was new.
So what did I discover:
– Hard vacuum tube (possible leak)
– Deteriorated plenums (definite leak)
– Square injector o-rings. (when wiggling the injectors by hand you created a definite leak)
– Broken intake manifold gasket. (definite leak)
– New injectors (No leak, but possible poor spray due to wear since they are mechanical)
Money spend:
Approx 500 USD (400 euro)
So reading out your spark plugs and spending 500 bucks, saved me money on a smoke test and the lady is running more economical
