Cat Control Unit

Considering that over 90% of the problems with a "slow down" light on a Ferrari is related to a fault in the detection system, rather than an actual engine running/catalytic converter problem, why does Ferrari use this system, when virtually no other car manufacturer does?

 

Bump!

FYI, I have reviewed some of the operation of this system and still think the CCU 'mystery' terminal is unrelated to ECU operation. If anyone has an internal circuit diagram of both the ECU and CCU, this would be of great help. This connection could be present "for future use" or just to allow using an available connector.

Rico!'s CCU x-ray pic does convice me that the CCU is a simple op-amp network with a VR; however, more precise diagram would be better for reverse engineering without sacrificing a unit.

Basically, I think, if you removed the cat, just remove the thermocouple from the CCU altogether (save it...it's an expensive item) and remove the bulb from the SLOW DOWN light. The ECU should remain unaffected.

Since the O2 sensor is installed in the (former) cat unit, I would just remove it from the system as well (save it too); the connector is just under the air cleaner box. The ECU (likely) has a "failed O2 sensor mode" which will introduce a "safe mode" operation for the fuel system; it will likely cause the O2 sensor variation from lean-to-rich-to-lean, etc, to stop and provide a constant fuel enrichment; I couldn't predict what the constant enrichment would be, however, it may actually be closer to the stochiometric air-to-fuel ratio (14.7:1 in mass units) than would be with the O2 sensor in place (recall, 80's-early 90's O2 sensors basically caused the fuel enrichment to oscillate so that the TWC could be more effective at removing emissions products; I doubt that any precise AF detector was available for road car use at the time). This should allow your vehicle to operate fairly well without a cat installed. If you could, after doing this, have the emissions measured (for a warm engine); we could see if the ECU mode for O2 sensor failure causes a reasonable AF ratio.

FYI, dynamic fuel system operation should be generally unaffected.

 

Guys, if you REALLY want to see how the thing works - do this.

1) Determine the type of thermocouple - you'll need the thermo and a technical oven for this.
(a nist-traceable voltmeter won't hurt either )

2) Buy a proper thermocouple simulator.

3) Connect simulator in place of the thermcouple and watch the outputs as you change the
"temperature" of the exhaust.

Now you know what it's doing w/ the fuel injection ecu and when/why.

The same non-destructive experiment can be repeated on every Ferrari with those infernal
"Cat Control" ECUs.

 

Not a bad idea...costs preclude purchasing NIST-validated/calibrated equipment. However, the ECU's response to calibrated CCU signals does require an understanding of the ECU's response to the signal (if any).

For now, Futureman should be ok running in open loop. Just don't get a smog test to pass emissions. Please do get one if you can w/o the gov't and let us know what non-regulated emissions are. This will be helpful for those wishing to drive and optimize fuel economy (and emissions) without using the TWC.

Rob

 

apparently, nobody really cares...

BUMP!

 

I cannot do the measurements at this time. I had a back injury last week and dare not bend over for any length of time.

 

I fully agree.

 

I went to GT, so I'm outside the Venn diagram...

Had a cousin-in-law go to Baylor...med school.