Possible CAT ECU replacement?

Link?

 

IIRC, that was developed by an FChatter (I have a recollection of seeing that before and a thread discussing it, but can't seem to find it now). No experience with it, but don't see why it wouldn't work perfectly fine. Not sure that I'd mount the display permanently inside the cabin in a visible way, but if you can get it to turn on the existing warning lights when an over-temp situation occurred (and I think you could), it seems a far better value than the present crazy price for the stock warning light ECUs -- JMO...

 

650 US$ only for 1 ECU with a little electronic inside?

that seems for me much money, even the thermcouples are not with.

but always cheaper than the original ones and this one will fit both sides. good idea !

I think an electronic specialist could do this with only material costs not even 50 US $. when I have time a little I will check and built by myself. until now I never have to use such ECU bec all my customers disconnected those.

I put in my car meanwhile 16 thermocouples only for exhaust and can see so always the temperature what it has.

 

Hello Christian, yes that's the instrument that Aerospace Logic & I developed to replace the dodgy Cat ECU's in our cars.

It's completely configurable (you pick your own Alarm & Shutdown setpoints) and it's the functional equivalent of the two Ferrari ECU's. It's also completely digital (after the A/D converters at the very front end of the circuitry) so it shouldn't have any drift at all. However, it's a derivation of a cockpit mounted flight instrument, so it's not suitable for mounting in the engine bay. Even if you don't care for the display, you should find someplace up under the dash to mount it rather than putting it in the engine bay.

One point I should mention - this instrument does not have a true analog output like the OEM ECU, but has three discrete states on its output:

1. Normal (a constant level DC voltage which is high enough to keep the Motronic ECU happy and let it know there is a functioning cat ECU in the circuit)

2. Alarm (a DC voltage, higher than "Normal" which causes the Motronic to produce the first "Slow Down" warning, but no further action)

3. Shutdown (a DC voltage which is high enough for the Motronic to produce the red, continuous "Slow Down" function which shuts down the injectors on that bank of cylinders)

It was designed this way to keep the existing circuitry that the manufacturer already had in the instrument for another application. I felt it did not compromise the operation of the instrument at all, because the display provides the actual temperatures seen by the cat thermocouples in real time.

 

If a 2-channel ECU for $650 upsets you, how do you feel about $2,300 for two stock 1-channel ECUs?

This is where Christian will have to do/add a little something different. You've (beautifully) done the much harder job of keeping a Motronic injection ECU happy and doing the right things -- what Christian has is a (more stupid) KE-Jetronic injection ECU with no intelligent connection to the warning light ECU. In Christian's case, he'd need to take your discrete multi-level output positive voltage signal and turn it into:

A. nothing/open when things are normal (so the warning lights in the dash are "off"), or

B. a ground signal that would turn "on" the warning light(s) in the TR dash when things are too hot.

Or, perhaps, you could add a "Jetronic" output terminal to your product that goes:

normal = open/nothing

alarm = flashes to ground for maybe 1/2 second at a rate of once per second (to flash the warning light and the buzzer)

shutdown = always ground (warning light and buzzer always "on")

 

A brilliant, well-executed solution to an age old Ferrari problem!

 

steve,

sure, the original prices are beyond good and evil
I only wonder why one should pay so much money for things nobody needs.

 

David, thanks for the kind words!

Steve, cheers for the insight on these earlier cat ECU's; when Aerospace Logic & I were developing the product I couldn't find anyone who knew the inner workings of the earlier models, so I assumed they were similar to the later ones. Bad assumption

Apparently our solution won't work "out of the box" for the earlier cars, but I'll contact Aerospace Logic to see if they could revise the internal circuitry to match the above requirements. Do you happen to know which other Ferrari models had this version of the cat protection system?

 

All of the "before Motronic", cat-equipped F (so 1978 US 308 thru 1991 US TR) use the same warning light ECU system/strategy -- i.e., the warning light ECU grounds one side of the warning light bulb to turn it "on" when it thinks the cat is overheating.

 

christian,
also here in germany our emission controls are not so easy to pass. but those ECU`s for the "overheating" nobody cares here if they work or not. only the driver may get crazy when those lights are always on. but for a new smog certificate this ECU is no important because it will be not tested.

also I wonder very about those lights there in the states where the cat´s normaly never get a too high temperature because of the speed limit you have there.

 

Adding the TR F PNs for this gizmo for searching: 61402500, 62347000, and 141037.

 

Easy solution. Run test pipes.. Problem solved.

R

 

Steve, thanks for the additional info & clarification. So if the sole output and purpose of this earlier model is to produce a single level ground return to a warning light, then I think the existing CAT202 instrument could work in this application, with the addition of external 5v relays in its output circuits. Here's how it would work:

Under "normal" conditions and normal cat temperatures, the CAT202 produces a 2.0v signal, which is not enough to "pick up" a 5v relay coil.

When in "alarm" mode, the above 2.0v signal will change to 3.83v, which is sufficient to energise a 5.0v relay. Once the relay is energized, its contacts can be wired to provide the ground path to the dash warning lamp. (Q: on these earlier cars, is there only a single warning lamp to take care of "both" cats, or does each cat have its own lamp?)

In addition, this relay will now effectively remain "latched", and the dash lamp will remain on until the car is turned off, because even if the CAT202 is reset and its output returns to 2.0v, that is not sufficient to "drop out" the 5v relay. The relay will not drop out unless its coil signal goes below 0.5v. This is a good thing, because people have been known to ignore & reset their ECU's on the later cars, thinking that the cat ECU was flaky, when it was not.

So only the action of turning off the engine & removing power from the CAT202 (or the incorporation of an external reset button for the 5v relay) would cause the dash warning light to go off.

That's the theory anyway. If anyone is interested to see if it works in practice, I can pick up a 5v relay and wire it into my own CAT202 and test it?

 

John - speaking for the Testarossa, there are two lights, one for each bank/cat.

 

Each cat has its own thermocouple, ECU, and warning lamp -- i.e., models with 2 cats have 2 thermocouples, 2 ECUs, and 2 lamps; models with 1 cat have 1 thermocouple, 1 ECU, and 1 lamp.

 

Christian, the 5v relay would be external to the CAT202.

I'll go ahead & order a relay and will report back once I've wired it up for a test.

Thanks Steve & Curtis, I thought perhaps there might have been a single warning light that both alarm relays could illuminate via diode isolators.

 

John,
What about case 0 - insufficient voltage from the thermocouple? Since you just have 3 digital states I fear this will get interpreted as case 1 = normal?
Regards,
Ron

 

I've started a thread on the 308/328 section to see how much interest there is in a microcontroller-based cat ECU replacement option priced at around $225.00 (for a 328 version):

http://www.ferrarichat.com/forum/308-328/498691-interest-slow-down-light-cat-ecu-substitute.html

The connectors and dimensions of the ECU box vary from Ferrari model to model, but as far as I can tell from information posted over the years here, the operation of the ECUs are the same (Steve Magnusson writes that this applies to K/KE-Jet cars, including carbed cars, from '78 US 328 to '91 US TR). The prototype I've put together handles grounding the slow-down light, with potential for additional diagnostics (for example, flashing the dash SD light if there's an error reading from the thermocouple).

Any interest in something along these lines?