Newbee 348 question

Welcome aboard friend

Just search this particular side of the forum, you will read a few problems others have with theirs and alot of good advice about repairing them so fear not about buying it, we will help you where we can.

I can enlighten you a little though....Welcome to the 348 Brotherhood where fine cars and even finer women will enter in your life
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How much?

 

Steve; When the car goes into "reduced power" mode and shuts down one bank of cylinders, it is telling you that one of the catalytic converters is overheating (thus the "Slow Down" warning). It needs to be determined whether this is a genuine problem or a false signal. The 348 series has a history of problems with the electronic control units for the exhaust temperature (the "black boxes" mounted on the rear shock towers). The thermocouple sends a signal to the exhaust ECU, which sends a signal to the Motronic ignition/injection ECU, which shuts down the bank of cylinders.

If it is a real problem, then the converter is getting very, very hot, probably due to unburned fuel getting into it. The first thing to do would be to download the fault codes stored in the Motronic ECU's to see if there is anything stored in the memory that might indicate where the problem lies.

If it's a "ghost" (a false signal) then you can do a simple diagnosis by switching the exhaust ECU's from one side of the car to the other, and see if the "slow down" indicator light now switches to the opposite bank of cylinders.

Neither of these tests involve any new parts, or special tools, or a great deal of time.

Hope the car works out for you, sounds great!

 

For your homework: http://webpages.charter.net/aircover/348/1994Ferrari348Spider.html

 

If it still happens on the one side you can try a couple of things.

You can swap the Motronic ecu's from one side to the other, not the cat ecus, the motronic ecu's behind the seats.

Or

When the car does it's thing, unplug the cat ecu for the 5/8 bank and then see what happens.

But it sounds more like you my have a bad thermocouple on the 5/8 bank. Your system could be working just perfect, but the thermocouple coming out of the can could be bad, or on it's way out. So try swapping the thermocouples from one side to the other and see what happens. You can do it yourself. A 12mm open end wrench, some WD40 to loose it up, and that's it. No need to get charged $120/hr for something that only takes 10 minutes to do.

Swap the thermocouples first, and see what that does.

 

As for funky problems on one side, my 348 had a bad fuel rail pressure regulator (the vacuum part wouldn't). The cat on the driver side was cooked, the tail light lens was melted. The problem would happen after a few weeks of resetting the motroic and as the car would add miles/data, I think it would lean out or enrichen the one side and the car would not idle properly. I tested it by hooking up a fule pressure gauge and then hand vacuum pump to the reg's port....it wouldn't modulate. Very easy part to install. In another adventure, I found a loose ground connection on the driver cam cover that would cause one bank to cut out. Good luck with your purchase. I wish all 348 owners could get 430's and pass our cars on to 308 and 328 owners so they could see what a good car is like! Good luck!

Jeff Pintler
89 348tb(getting major now), 86TR(bad clutch master)

 

Where was the loose ground connection, specifically?

 

I was wondering that also.....

 

You might want to get some test pipes and disconnect the exhaust ECU from the engine management temporarily (wink, wink). I am getting my cats tested currently. Sounds like you have found a great car, good luck!
BT