CEL 1/4 light and rough idle

I had this problem with my 348 when I first got it. I would get the slowdown light and the car seemed like it would lose about 100 horsepower. Then about a minute later it would die. It would start up immediately and be just fine for about 20 miles and do it again. I switched the cat ECU's and it actually ran fine for awhile. After about 300 miles it started doing it again but it of course had switched to the other side of the engine. I then changed that ECU and there have been no problems since then. I do not have any pictures but I found some on Ferrari Chat when I was trying to figure this out. I know that Miltonian has some posts concerning this problem.

 

Did you pull the codes? Get those and it might get you closer to the issue. Don't get to stressed with CEL's, most are nothing and it could be just bad electrical connections. If your 02's are old I would think about replacing them. I had a similar issue and new Bosch Universal 02's solved the problem. There are threads here with the proper part numbers.

--Mike

 

Hi, Dustin. Congratulations on your 348!

The "slow down" lights and the "check engine" lights are not the same thing, just to clarify. If you are getting "check engine" lights, you need to download the stored codes, find out what they signify, then clear the memory from the Motronic self-diagnosis system. You can do that at home yourself. One of the problems you may be encountering is a bad ground on the O2 sensors, as you have said. It's pretty straightforward to just make up a wire that can be clamped onto the sensor body and grounded on the frame. There are all kinds of things that might be triggering the CEL, most of them being pretty minor. It's also possible that you just have old codes in the memory, and if you clear them, they won't reappear. At this point, just don't worry that a "check engine" light means "immediate danger". It just means that one of the monitored systems has shown a reading outside its normal range. Don't ignore it, but don't panic.

 

Disconnecting the battery will clear the codes. To get the codes you need to remove the panels behind your seats. There is a button on the ECU that will allow you to get the codes on the dash for each bank of cylinders.

Go here and follow the procedure:

http://www.my348.com/348.html#ECUcodes

You can do most of the work on a 348 yourself. By the way that page is a great reference for anything 348.

--Mike

 

I suggest, after you unplug the battery, to use a contact cleaner and spray both ECU's connectors, MAF's and anything else with connectors in then engine. This is very easy and .... works. It really helps !

 

Dustin,
Sounds like me 6 months ago. Take a deep breath and relax, we ALL have had similar issues and ALWAYS at first it seems a huge problem, but these are great cars and quite simple to do the work yourself on many items. No really, it's a lot of plug and play items (remove the old one and put in a new one) sort of thing. I replaced the two O2 sensors in mine in about 20 minutes absolutely no big deal and it now runs great with no warning lights. cheap and easy fix. Next is the fuel pump regulaotrs so it starts back up right away after being off for 15 minutes. That's another "everyone" issue with these cars. Go to the my348 page noted in the forum and you can download instructions and pictures for doing just about anything!!! send me an email if you need help reading the codes, again, really really simple to do on your own, don't get too anxious about it.
Steve
btw, your profile is still empty so we don't know where you are

 

Have you "re-initialized" after having your battery unhooked?

Glad the car seems to be running well!

 

Ditto, did you let the car idle without touching the gas pedal till both fans came on or roughly 15 min? this resets all parameters.

 

Best of luck with your car Dustin. I think if you try to search most ANY issue you have with your 348, you will find a wealth of information from this forum.

 

+1