Interesting 1995 F355 issue

I have read that compression test should be done cold but I am not sure why? Maybe someone else can confirm

 

Boy, I'd do a little more thinking and testing before I pulled the engine apart with good compression and leakdown number like yours.

Could it be a bad EGR or other emission system gone wonky? The fouled plug/misfire might be a result of something more simple!

Call some of the pros on Fchat and see what other things to check before dropping the motor.

 

Could be a broken oil ring in that cylinder. Hard to say. Its sounds like you know what your doing. If your taking out the engine yourself then go for it. If your paying someone to do it, then look into it and ask around a bit more before paying out bucks you may not have to.

 

If hes getting that much smoke....I doubt it would be the egr.

 

Not much experience with a broken oil ring but would it smoke more when cold or warm

 

I would remove the header and the intake manifold and look into the cylinder that is fouling to see if the valve stem seals are torn and leaking badly. You can see it from the ports.

 

Hard to say. Should be less when warm but I cant say for sure. The valve guides tighten up when warm. If I go by the shop tomorrow I will ask Massimo what he thinks.

 

Does it smoke on throttle (acceleration), off throttle (engine braking), or all the time?

 

It sounds like you are a very sharp owner, but I keep thinking about the fact that you just did a oil change and only drove 15 miles before it sat for awhile and then started smoking.

Is it possible that there is anything related to that job that might have caused this smoking? Triple check the oil level? Trash in the scavenge line, blocked screen, etc?

As my flight instructor used to say, "If you pick your nose and the engine quits, put the booger back in first"

 

+ 1 - rule out the simple stuff first

 

Maybe one of the cats is desintegrating causing the smoke, and tripping the O2/Thermocouple sensors causing a slow down type condition...

 

Can't diagnose a motor sitting on the garage floor.

Bad cat does not generate smoke

Ferrari has not had EGR since 1983.

Guess work of this nature will not lead to a diagnosis.




Ferrari installed plugs in every tube of the exhaust manifolds to allow exhaust sampling for diagnostic purposes. Use them. Once it has been narrowed down to an offending cylinder or cylinders, you know where to focus your energy.


You have a number of diagnostic tools at your disposal that have yet to be used and none of them are any good with the motor out.

 

I am just curious. Please explain how that can happen.

And what is "a slow down type condition"?

 

You're right of course, I actually meant that there may be issues other than mechanical failure here and jumping right in to yank the motor and tear into it did not seem like the right plan until other things were ruled out. Too many 308's in my past I guess

 

You're correct. It is much easier to do diagnostics when it is still running.

Even after it is diagnosed, no reason to think at this point a repair will require removal.

 

I'm for eliminating the easy stuff too.
You did an oil change.
Did you switch from Dino to Synthetic, or from a thicker weight to thinner?
Both of those have caused me headaches in the past on a 308.

 

Good luck Jordan. Keep us posted.

 

It will be interesting to see what you find when the engine is out. When I had my engine out for service we did a leak down and 5 of the cylinders were worse than yours and yet the car never ever smoked and it ran strong. We did the valve guides and the car has more power but we did other things as well. I just don't see that much oil getting past just one valve guide.

 

Jordan,

I would be interested in the results of a hi pressure FAA leakdown test vs a low pressure leakdown test. There are some who swear by the low pressure test being more able to adequately diagnose especially the 355 due to the design of the guide and valve and how both influence the seat. It would be very enlightening if you actually find much more leakage with a low pressure test which would then start to lead you away from simple fixes. Not knowing the real science behind hi vs. low pressure testing now I just do both of them and tally both results. FWIW, the 355 valve guide seal is better than the guide. That's one reason why several have reported no smoking yet bad guides on their cars. Make sure you fully diagnose your car. The worst thing that could happen is you pull the motor apart then freshen it beautifully only to fine it is still blowing smoke when you run it.

 

What are the pressures associated with each?