I just purchased my first Ferrari and I am starting to learn about the car, 92 Mondial t. What does it mean when the slow down lights go on 5/8 and 1/4?
BAD CAT ECU'S...BAD GROUNDS...BAD THERMO COUPLES...OR WORST CASE, AIR FUEL MIXTURE OFF, TIMING OFF, OR CATS CLOGGED CAUSING ENGINE TO PRODUCE EXCESSIVE EXAUST TEMPS. JUST HAVE TO LOOK INTO IT...
The "Slow Down" warning was a poor choice of words. It is an indication the cats are overheating. It is often an erroneous warning but needs to be taken seriously.
Welcome and congratulations on your purchase. There are many many threads on the slow down light so the responses get a bit thin on new threads of this order, but you got two very accurate depictions of your issues. If after searching/viewing other threads you have specific questions there may be clarification available. It is a common issue and one I have on my 3.2.
First try to swap the sides and that will confirm if you have a faulty ECU. if not it should be your fuel mixture or bad exhaust thermos.
My wife and I took our Mondial 3.2 for a long highway drive today. It did fine going 100 miles and then returning another 100 miles. We then stopped the car at a friends house to pick up our kids. Now when I stopped at their house, I really didn't let the engine idle for a while. Thirty minutes later, we all get in the car and the slow down light is on, and the car is in a low power/limp mode. I limp it back to my garage, open the trunk and there's a lot of heat and some smoke coming off the cat. It hasn't cooled down yet, but does this mean my cat is bad? The car was definitely hot from the long drive, but was fine until I stopped and restarted it. I've read some threads about the thermocouple and the ECU. Does anyone know if the slow down light comes on, does that somehow cause a limp mode/loss of power or did one of my banks fail? What order should I test it (thermocouple....ECU....electrical to one bank, etc.) or should I just take it to my F-mechanic as a precaution. Thanks in advance. Jay
This is NOT a limp home system, once the light goes on, and you feel the power down, one of your banks isn't firing. What is happening is you are dumping gas into the cat, and it goes on fire inside the cat, can make the cat red hot (and can burn down the whole car!). Slow Down should instead say "Stop Right Now and Turn off the Engine" (if you are down on power, if you aren't its probably the electrical contacts at the cat "brain" in the trunk, and you can clean the sensor with a brass wire brush, usually stops the light from going on when nothing is wrong). Your warning system functioned correctly, so not a problem with it. The issue is what caused the bank to shut down. Probably a failed coil. The coil is expensive, but easy to replace. You could try swithing the two around, and if the other bank doesn't work then you know you have the problem. I would replace both, as if they are original they would be best replaced anyway. Of course it could be other ignition system components, or the main computer, which is best left to a dealer with the SD diagnostic equipemnt for this car. Don't run the car for more than a brief period when doing this coil swap testing, you will be dumping gas again. As for the cat, since you drove it, lots of gas dumping means it got REAL hot. It is possible (probable? I am not sure how hot for how long will melt the inside, maybe others can provide a better view of the odds of cat damage) it is damaged. OEM cats are ridiculously expensive, get a hyper cat, its lighter and more efficient anyway. The O2 sensor might also be damaged from the heat. Ferrari didn't really engineer this well, there should have been some fuel cut off if the warning light went on, and a bank was not firing. Most people don't treat warning lights as seriously as this one needs to be treated.
Thanks for the reply. Yeah, my cat was VERY hot when I got home. Now it's cool. I was able to start it, but still sounds like a bank went down. So I'm going to send it to my mechanic to get checked. But how do you know if the cat is bad?
By the way, the slow down light is now off, like it's supposed to be, but I'm not going to drive it until it gets checked about. I still have a power issue.
Hope it's not your coil. In my case it was the spring in the distributor cap hanging up due to dirt and poor contact on the rotor. Cost to repair was zero thanks to helpful people on Ferrari Chat.
The slow power issue is probably caused by a missfire/igntion problem on one bank. This causes raw fuel to be dumped into the catalytic convertor, where it is burned. This causes the catalytic convertor to overheat, I have seen them glow orange from getting too hot. If driven too long in this condition, It will damage the catalyst. Once you have fixed the missfire problem, you can check catalyst function with an exhaust sniffer to see if it is still functioning, otherwise you can physically inspect the inside of the cat for any heat damage by removing it, or we have a tv camera that we can run down the O2 sensor bung to look inside the cat. If you didn't drive the car too long with the light on, it will probably be ok. Brian Brown Patrick Ottis Co.
On my Mondial 8 it has been either dirty distributer contacts and/or fouled plugs causing a misfire. Cleaning these at 3000 mile intervals has worked as preventative maintenance for this. I have found that running hard through the first 3 gears once warmed up at least once a tankful helps keep the plugs from fouling--sounds nice too.
In my case (456GT) there was a simple and inexpensive reason for the cat to be running hot. Two 'bad' plugs! Don't to this day know why but two plugs were not firing and as others have commented, raw gas was being sent into the exhaust/cat, makes for a really dangerous amount of heat! If your motor is not running smoothly, maybe check to find the 'rough' cylinders and see if the roughness follows the plugs when you move them. In my case the plugs were actually wet! Tried two new plugs and the roughness and the slowdown light went away for good. just a thought . . .
