Nightlife 0 compression found and cause.

One thing that has me a bit puzzled is the function of the O2 sensors here.

Lets assume the car has no thermocouples and the CAT ECU functionality is gutted entirely. Now, lets assume the car is way out of tune and the cats massively overheat. Wouldn't, at a very minimum, the O2 sensor freak out and send a CEL ? The sensors are post-cat, so as the poor catalyst barfs its guts out, more 'dirty air' makes it back to the sensor, thus triggering the CEL?

 

348 and 355 2.7 has only pre-cat O2 sensors.....only thermo-couples are post-cat

 

Do you know what your MAF settings were? Should be around 384 on both sides. How old are your 02's? These two greatly effect lean/rich conditions.

--Mike

 

This makes sense Daniel - let's see what the experts have to say about this.

 

+1 ...... another thing I forgot to mention was that 348s have a 'solid lifter' mechanism ...... so valve lash should be checked regulary and shim adjusted ...... because valve stems sometimes stretch and or valve/seat interface wears just enough that they will not fully seat/seal .......... if exhaust valves are not seating/sealing properly ...... they will get extremely hot from combustion gasses getting past them (the valves depend on seat contact to dissipate heat) ....... then the red hot valves can create a secondary ignition source causing preignition and or detonation .......... then coupled with the 348's lack of knock retard ignition ....... it will not take a lot of lead foot before one detonates a hole in a piston or burns up a valve(s) ............. and takes out a cat(s) along the way ............

 

As Daniel pointed out in post 10 and I agreed with in post 12, the cat did not cause this problem. It is a symptom.

 

Night - when was the last 30k service done on your car? Were the heads opened up at that time?

 

As are most guys following this thread, I am anxious to find out what happened here.

 

I agree.. its my recollection that OBDI cars only have 02 sensor before the cat.. OBDII cars (some of the F355) have pre and post cat 02 sensors (4 total). The o2 sensor could go bad or lazy for a number of reasons and signal a lean condition and the car would richen the mixture which could burn up the cat.. dont think the are designed to light off lots of raw fuel consistantly being thrown at them..

Not sure if the 348 have a PE table in the software that ignores the 02 sensors at WOT.. but that could also expalin if the sensor were good why they didnt adjust the mix while the car was being 'enjoyed'.

 

ND has the software decoded and maps. Assuming he's not out drifting his 348 , I'm sure he'll have an answer on this one.

 

Um, not to hijack this thread, but on similar notes might have an 'issue' regarding the 456 that, although not possibly the same, might just be in this same problem area.

Will be packing it up soon when there is an opening

....not looking fwd to the verdic, but, it does need to be sorted....and such is the way are Ferraris can go.

 

Ouch....good luck and I hope the damage is minimal.

 

x2.,.


also to the op.. I've been thinking.. since all the pistons seem to be a bit burned up.. I'm wondering if the one that failed was just the first in line to fail and the rest were not far behind.. Seems like things may have been lean.. and if the whole bank went lean I would wager a guess the ecu told it to lean out the mix.. maybe indicating a bad 02 sensor on that side...

 

Before the teardown it would have been interesting to report on what the timing numbers were. I bet that was not done.

 

I'll post when it's corrected. It's going into good hands.

 

I'll post when it's corrected. It's going into good hands....but <sigh> anyway.

 

Possible alternative? http://cgi.ebay.com/ebaymotors/Brand-new-1994-Ferrari-348-Crate-Engine_W0QQitemZ250518621537QQcmdZViewItemQQptZMotors_Car_Truck_Parts_Accessories?hash=item3a5412cd61

 

Wow, I didn't know there was any "new" motors like this still left!

 

Poor Roberto .... what a nightmare this has to be, I feel for you man ...

Our cars ... a lots of joy and pride but also .... pain.

 

Actually the other three holes look like there ok, and based on the compression #'s they probably were. I had the same amount of carbon when my heads came off at 31K. I'm wondering what the faces of the exhaust valves look like.
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If you go back to his pictures in post 46, do you suppose it's significant that the major wear on the #1 piston and cylinder is at the low spot, gravity-wise? Perhaps the injector was stuck open and raw fuel was accumulating at the low spot while the engine was shut off, and washing the oil off the rings and cylinder walls, specifically at that low area?

You definitely need to get the injectors tested before putting them back into the engine!

We need to see pictures of the heads/valves.

 

Holy crap Roberto sorry for your luck! You gotta look at the bright side she will be better then new when your done. I will be taking a close look at my cats and any powder residue on my end in the spring. You gave me a lot to look out for when I pull her out next year.

Very informative guy's on here with lot's of good advice, Thank's for that.

Cheers!

 

Whatever it is it seems to have affected one cylinder. Injector nozzles are the most neglected thing on these motors. I am finding, with the gas we have now that real benefits can be had by removing and sending them out for servicing every 5 or so years. We have traced many running problems and CELs to injectors in recent times. I am lucky, one of the big companies doing that is about 10 miles from here.

 

Gotta agree with RD here. A fat condition won't create enough heat to burn a piston like that. It's a lean condition that creates excessive cylinder heat. Fat just causes "blubber" and black.

 

Super obvious, and I don't even have a spyder. Like ridding a motor cycle in smog traffic obvious. Like an F1 crew member, that splashed a little gas on himself obvious. Like leave it in your garage with door cracked halfway and still pass out 15 minutes later obvious!!

You have to drive fast at all times to keep the stink behind you, so great at the track, horrid on the street. Though never any over heating or other issues, loves revs, so hoping this isn't another Ferrari catch 22.

I'm going to try and tune mine with a 30K service though to see if its not exceedingly rich, but been told its common with no cats on these cars.