Slow Down issue -Suggestions before I sell?

You could start by listing it as is, but listing that the slow down light is there. Be upfront and you probably won't have any issues. If the buyer is from a non emissions state they may want the test pipes. Or they may ask for the car to be fixed back to factory. But no need to spend money that you may not have too.

 

Cats do not cause slow down lights, they only overheat as a result of excess hydrocarbons from poor running. You either have a bad warning system or a real running issue in spite of the recent service.

I recently finished replacing a bunch of melted cats on a 575 that went through 2 majors with a cam timing issue. They kept replacing $14,000 worth of cats without diagnosing the cause.

 

Brian, Can you elaborate a bit on what you mean by a "cam timing issue"? how far off was the cam timing? was this due to a lock and swap. Was it just incompetence?

 

Incompetence.

3/4 of the mechanics have no idea how a car works. They are just installing parts. Ferrari's and Ferrari dealers are not immune.

The fact that there is so much internet lore that a bad cat overheats is in support of that. Bad cats don't overheat. Overheating causes bad cats. Poor tuning causes overheating. The solution to many is to either replace or get rid of the cat. That's kind of like taking pain killers for a bad chest pain.

A clean running car is a good running car. If you are pumping unburned gas and or oxygen out the tail pipe you have lost performance but the concept is lost on most.


At first major shop mistimed the cams. Some time later cats melted and were replaced. Problems with warning lights continued owner got disgusted and sold car. PPI shop sold another major and did not discover bad cats (Ray Charles must have done PPI). Belts were installed with cam timing not being checked. Car came to California and $22,000 later it runs right and passes smog and has no more catastrophic oil leakage from poorly installed gaskets, seals etc.

Why people persist in buying a car cross country, having it inspected and serviced by a shop they have never dealt with before and will never deal with again is incomprehensible to me. For a small fraction he could have flown me to look at it and if needed had it brought here.

.

 

LOL! About a year ago I picked up a concourse level 550 which had been through 4 Ferrari mechanics and multiple cat replacement and finally a burned cat that could have become a real fire but instead only melted some stuff. The owner got fed up with it and now I own a perfectly running 550. I bought it nearly sight unseen thinking I was going to make a cheap racecar. I could not bring myself to chopping up a beautiful 550 so now I got 2 of them. First world problems!

 

What was wrong with yours?

I had a 456 here that literally melted the back half of the cat off. It had to of been close to a real fire. Much of the heat shielding was just dust.

 

Nothing wrong with mine. I'm just a sucker for a deal I could not pass up. I'm just not in a position to see a lot of diamonds in the rough so if I see them I buy them.

The 550 I picked up had this cool 1" hole burnt through the thick cat metal and the heat shield. This was close to a real fire too. Looking back over the service records the 20/20 hindsight was obvious. Part replacing!

 

Ferrari had issues with spark plug wires on the earlier 456s, such to the point that plug wires were recalled. Mine were replaced in 2001, and may be identical to the ones on your car, but the plugs on the coils closest to the exhaust heat shields were still completely shot when I bought it. The damage was all internal and not visible from outside the plug. It would probably not have been caught during a normal service.
Also, these coils use waste spark setup. Each bank of 6 cylinders has a coil block that houses 3 coils, each firing 2 plugs. Hence, failure of 1 single coil causes 2 cylinders to pump combustible gas into the catalytic converter, an event that will overheat it in very little time.
There are not many people that will easily notice that their 12 cylinder is now running on 10, and if they also fail to believe (or adhere to) the ensueing slow down warnings, then the cat on that side will be toast.

 

Also, I'm not convinced the OBDII misfire detection works properly in our 5.2 Motronic's, hence the need for these catalytic converter ECU's. I don't know how our algorithm works, but some misfire detection schemes depend on detection of loss of engine speed or torque, which becomes increasingly difficult with the greater number of cylinders, ie it works OK for a 4 banger when you lose 25% of the engine torque when one cylinder misfires, but not so well on a V8 (12.5%), and probably not at all on a V12 (8.3%).

Interesting that BMW have the same P/N Motronic ECU in their V12's of the same period, but they don't have the cat converter ECU's in their system. According to BMW owners & technicians I've spoken with, their ECU's do detect ignition misfires, and they do set MIL's.

On our cars, I've seen the code for random misfire come up, but only when the two throttle bodies weren't synced, not when there was a true ignition misfire.

Apologies to the OP for the drift.....

 

When one of my fuel pumps lost most (but not all) pressure, I got misfire codes on all six cylinders on that bank, and none on the other side. Seemed like it worked properly to me.

 

I also think the misfire detection works fine and to a very precise level. In my own case had random misfires and specific misfires only after about 100 miles of running after code reset. I Was doing debug near time for first major under my ownership. Narrowed down to injectors. Had injectors cleaned and balanced withone injector slightly out of spec. Put in car and only one code after about 100 miles of driving. It was the one mildly out of spec injector. Bought one new injector and all is fine in the world. I don't know the inner workings of 5.2 motronic. Maybe when you got two 5.2's splitting the engine into two sixes the motronic can't shut both banks down if there is a major fault. Maybe the simple legacy solution for Ferrari was the sdecu. Ferrari had used that kluge for decades.

 

Sorry, I'm referring to ignition misfires.

As a test, I disconnected one bank of the ignition from +12, and the injectors on the dead bank continued to inject, but no MIL's or no error codes were generated. Not a good situation, and I feel that this is the real reason we have this secondary Cat ECU protection system.

 

Whoa...that's nasty! Isn't a whole bank down the ultimate misfire? I wonder why this does not throw a code.

 

Carl, I don't know, but it certainly makes me want to keep the Cat ECU system in good working condition! Maybe someone who really knows how to drive an SD2 or Leo could investigate this further?

BTW, I confirmed this on 2 different 550's.