Rookie in need of assistance '94 348 Spider

Yes, sound reasonable, these little B@stards are not cheap either. You should not have any problem with the aftermarket exhaust, I know of a few owners that have done this already with no side-effects.

 

Extremely reasonable. Check to see if the Cat ECU's have black epoxy seals or green seals. Black = old and yucky. Green = fresh and yummy.

 

Hyper-Flow cats and Tubi is/are a good upgrade. You might, repeat, might run a wee bit more lean than before due to their better gas flow, but typically the Motronic 2.7 adjusts to them after your first ECU reset.

They are not known to cause cat ecu problems.

That being said, if you have been getting SLOW DOWN lights then you will want to check your main air fuel Motronic computers' error codes.

A real cat ecu error is supposed to be accompanied with a 4122 cat-temp-too-high error code. It would be good to know (for you) if you got it or if your exhaust ecus were just throwing your SLOW DOWN lights without sending errors to Motronic. or whatever. Anyway, just check your error codes (see link in my signature).

 

Welcome to FChat, you just found another place to consume your time, HAHA. This is a great forum, sometimes people get emotional, but there is a wealth of knowledge in here.

 

technically, the temp sensor is the probe (thermoprobe) shoved into the cat itself. The cat ECU is the little computer box that interprets the temperatures from the probe and takes some electrical action (or inaction).

 

Yes that is correct. The Motronic ECU controls the engine. They are the units that shut the engine down when they get a over heating signal from the "cat ecu's". There is a difference between the sensor, and the cat ecu. The "cat sensor" is actually called the thermocouple. That is the thing plugged directly into the catalytic converter. The thermocouple acts as a thermometer, which then sends the catalytic converter temperature signal to the cat ecu, which then sends that info to the Motronic ecu.

No.

In order to reset the ecu's, you need to disconnect the battery. After the car has sat all night, disconnect the negative cable from the battery, wait about 15 seconds then reconnect it. Now make sure that the car is out of gear and start it. DO NOT touch anything, just let it sit and idle for about 15 minutes, again WITHOUT touching ANYTHING. Not the clutch, not the breaks, not the throttle, nothing. You will hear the engine changing rpm's as the Motronic ecu's relearn the warm up parameters. After you hear the cooling fans kick on at least once you should be good to go. Now take it out for a nice 30 minute drive.

 

I think you car is shutting down from excitement over your girl!!!