Ferrari 412 - Failed Inspection. High HC and CO Values

Actually testing your exhaust is one of the ways you know your timings are off ..all things working of course

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Well both actually.

FYI I have a lot of experience with 400/412 and also California emissions.
That is real high. Do you by any chance also have O2 and CO2 numbers? Be a big help. Cam timing marks mean little on those. Flywheel marks on the other hand are usually pretty accurate.

Did the cams get degreed when put together and do you have an exhaust gas analyzer?

412 has electronic advance, it is adjustable but leave that for later. It is so rich, just adjusting fuel mixture might fix it. You had both fuel distributors rebuilt. How did you set mixture afterward? Simply cannot be done by ear. How did balance, idle etc get set?

 

Cam marks are there to aid in assembly so no damage is done until they are degreed and can make a very big difference. Here are some pictures of cams properly timed.
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Have someone who is very experienced in the process degree the cams. Until that is done all else is just a waste of time. The factory went to the time and expense to do it that way on each and every car because it is vital.

Also, diagnosis with only 2 gases is pretty much a waste of time. In this case for example I know the CO2 will be down around 4 or 5 % but if all 12 cylinders are firing and O2 is at 1 % it is too rich and might be cured by adjustment. If on the other hand O2 is at 4,5,6 % The cam timing is off and we don't need to waste our time. 2 gas readings are good for crude adjustment on a motor you know is perfect. 4 gas is for fine adjustment or any diagnostics.

When cam timing is off they never will run well at any mixture near correct. Richer will always run better. The smell is HC. HC goes to the moon with a cam timing issue.

 

Yes, we do it all the time.

You need to start with the cam timing. I am confident there will be other tuning issues once that is known to be right.

 

The car seems so toxic that I would try adjusting it by "ear" and identify the source of the issue.

First check with a timing light that both banks are correct (you will need a light with a long cable), then just go for the leanest setting. The idea is to make it slightly rough which will help for the diagnostic.

On my car, the setscrew is very sensitive (even by ear): 1/8turn richer and rpm gets rough, 1/8 leaner: equally rough. So there is basically a 1/4 turn margin. If the adjustment range is larger, something is wrong with your setup.

Once the engine has a lean rough idle, check the temperature of the individual cylinders (spark plug and exhaust ports). If there is a significant difference across cylinders of the same bank, you have a problem with your k-jet (or a leaky valve). If the temperature is homogeneous, lean the mixture more and check temperature again, if the temps are still homogeneous chances are camshafts are not properly timed.

In order to make it easier, you could lean the banks individually, so as to let one bank of cylinder keep the engine running while you "starve" the other bank for testing.

 

Bad timing has a huge impact on exhaust temp (retarded = more heat = less HC), but should not foul the plugs, at least not with camshafts aligned on the factory marks.

I would further investigate ignition and mixture. Maybe your cold start enrichment is way too rich, which could kill the spark plugs before reaching operating temperature.

When messing with a poluting car I just use regular copper plugs, ideally on the hot side and with multiple ground straps (ex: Bosch F5DTC). At least these do not get fouled easily and are less fragile than thin tip plugs. They can sustain an overly rich tuning while I adjust the mixture.

The expensive plugs are installed once the engine runs properly.

Also don't forget that clockwise is rich, anti-clockwise is lean. I know you know it

 

The cam timing is different. Everything an experienced Ferrari mechanic needs to know is stamped on the flywheel and printed in the owners manual.

I am not going to teach advanced auto repair on the internet nor am I going to argue with those who do not know how to perform diagnostics.
Once the cam timing has been set properly by someone with the proper experience I can help.

 

The cam timing is not making it rich. It has been adjusted rich because its required to make it run when cam timing is incorrect.
I already explained that.
All the flywheel marks will be used.

 

This is very nearly 100% wrong.

 

PM me if you want advice. I will not get involved with this conversation any longer.

The advice is very poor and I am not into arguing.