Ferrari 348 hot start - does not hold the idle

I am guessing bad coil but that is just a guess. It could be the power module for the coil as well. I have used ones that I use for diagnostic work. I have had both coils and power modules fail. Find a quality shop and have it properly diagnosed. You can also swap the components and see where the issue goes and then replace that part.

 

The left bank crank sensor is faulty (that's the one on the side of the crank, not the one on the bottom). That will affect the tachometer and give you running problems.

Image Unavailable, Please Login

Check the connector. Sometimes they break or get contaminated with oil. If you fit a new sensor, make sure that it has the correct clearance from the teeth on the crank.

 

You can get to it from the bottom, but it's still very difficult. The connector should be easy to get to, however. The sensor itself may need some creativity to get to. Watch out for loose shims on the sensor.

 

I would say one, or both of your fuel pressure regulators are bad. Very easy to check. Simply check if raw fuel is leaking from the vent at the rear of each regulator.

 

Front of engine in front of fuel rails both sides, a little can with 2 Fuel lines and a vacuum tube. Fuel filter line goes to it. Check 348 forum there are posts on replacing them.

Sent using FerrariChat.com mobile app

 

This is it. Image Unavailable, Please Login

Sent using FerrariChat.com mobile app

 

I doubt it's the fpr. Just explaining where it is since you asked. I would pull the passenger foot plate and check the back of the footwell fuse box. I know a car that had the same issue symptoms and the fuse panel and melted where the power lead connects. When it cooled it worked. No start until cool and if it did it ran on 1 bank poorly, others electrical gremlins on and off like tail lights did not work etc.

Sent using FerrariChat.com mobile app

 

The tachometer is the biggest clue. It's either not working because the crank sensor has failed, the left hand Motronic ECU has failed or the tachometer itself.

I don't think it's a tachometer power issue (at the fusebox) as that would affect all the instruments. I suppose you could be losing power to the ECU. Check power is on fuse 14 in the passenger footwell next time it happens. Ignition (key) power also goes to the ECU via the relay panel, but there are no fuses for that.

 

losing power to the ECU - Exactly fuse 14 is mighty close to the power connection on the rear and if it melts it affects other circuits. Not saying its the issue but I have seen this before.

 

If a crank sensor fails, don't you get a Check Engine warning light? Also, would you be able to get an error code via the OBDII plug?

 

Good point. I don't know if Teo was getting a Check Engine Light.

The ECUs provide both power and an earth to their respective CELs. If the ECU is completely dead, you shouldn't get a light. This may suggest an ECU power issue.

I don't know if European cars were fitted with ECU test buttons. Teo may not be able to get codes without an SD1 tool.

 

Nor on any 348's. Check for a test button near each of the ECUs. Do you have a Workshop Manual?

Interesting. Did you notice if both CELs illuminated before start? If you get no start or lose a bank again, turn off the ignition and then turn on again to see if both CELs illuminate.

 

Ah, now you've got me thinking. I read that early cars ('98) don't have CELs and European cars may not have them.