The car: 1998 355F1 spider Despite installing all new cat ECU's, Thermocouples & O2 sensors I am still getting a 1445 code and a slow down light. The car has fabspeed headers, high flow cats & a tubi exhaust all appearing to be in good shape. I can clear the 1445 code and the SD light goes away. Drive around town for 10 minutes and it begins to blink and the 1445 code is pending. Initially I thought I had a short in the system or thermocouple somewhere and it was now time for me to chase the wires. Having gotten a little frustrated, I decided to give it the Italian tune up. After a spirited entrance ramp drive that took me to redline three times, the light went out. It stayed out the whole time I was at highway speeds. Never did that before. After exiting and driving at city speeds, it flickered a bit, then went back to blinking. An IR thermometer check shows that catalytics at 350 - 400 degrees so there isn't an overheat condition. Obviously it is reading something so I'll assume the wiring is OK at this point. The car runs smooth, idles fine and seems to be operating just fine.....except for this issue. I still have the 0422 & 0432 inefficient cat codes (courtesy of the high flow cats) but I do not think these are related to the 1445 & SD light. Could they be? What would cause the slow down light to go out as you go faster???? Thanks all for any guidance.....
Will the Italian tune-up work if you are not Italian? I have always wanted to know the answer to that question - that, and does the I.T.U work on non-Italian cars? How about if neither the car nor the driver is Italian? OK - back on topic... To answer your question - I think at higher speeds the ECU is looking for higher temps so you are fine, at lower speed it's seeing the temps too high (either an inaccurate sensor or temp is too high) I am starting to think that Ferrari is using these thermocouples to try and monitor AFR - maybe we should have AFR meters?
We use K type thermocouples on aircraft engines to measure EGT which is what I would assume is being measured here, and compared against acceptable ranges. These thermocouples are very sensitive to connection quality and wire type. I doubt Ferrari paid as much attention to these factors as we do in aviation. My off the cuff thought would be first the quality of connection as has been identified with Dave Helms' gold connector kit. Unless your cleanly connected to the measuring instrument (ECU in this case) all other bets are off. Second the wire quality and shielding are big issues in aircraft, again I doubt Ferrari paid the same attention in monitoring for EGTs which how many other cars on Earth do. My instinct would be to look into the wire loom and connector quality between the thermocouples and the ECU. As a guaranteed to be controversial solution, my view is that given the types of use under which an actual cat overtemp is possible, the slow down light is an idiot light where a gauge should be. There are systems such as Altronics http://www.altronicsinc.com/pages/redalert.html that can provide alerts when and logging of data. Perhaps giving the ECU a value that is always "valid" and installing such a system with a thermocouple in each bank after the cat would be less expensive than chasing the O2 and thermocouple replacements and would provide much more useful data about what the temps really are, as well as when and why.
I believe you are correct. In aircraft the EGT is measured to approximate the AFR - in cars we have already found that a wideband AFR meter is more convenient (read "accurate", if you will) You have hit upon a great point, the light is only a light. If all drivers were aware of the values and what they meant, the car would come with a gauge. I am all in favour of "fooling the ecu" and using actual gauges to determine the state of my engine.
"In aircraft the EGT is measured to approximate the AFR - in cars we have already found that a wideband AFR meter is more convenient (read "accurate", if you will)" Exactly, we look for peak EGTs and (depending on practice) fly lean of peak. For the car the O2 sensor is providing real AFR data. There are plenty of instruments out there to monitor and alarm EGT values. In this case a two sensor system at the cats would be my move, you could go with one on each cyl but that won't necessarily reflect what the cats are doing.
