Hi, I just replaced one bad ignition coil on my 575. The car still has rough idle and sometimes it runs only on one bank which I can not rev over 4000. I have tried restarting the car 2-3 times and the problem is gone. It already happened 2-3 times. Can anyone suggest me what to look for?
Are there any engine warning lights when you are running on one bank? If the ECUs are holding the revs to a specific limit, it sounds like the bank is missing sensor data or sensor data has gone out of a safe range. Does your car have an OBD2 port?
Replace the other ignition coil pack! min started to run occationally on only one bank, but still got fuel so backfired like hell in the exhaust. The engine room is so hot so the coilpacks can’t last forever. Just replace it and you know it will be good for a new 15 years or so.
Erik, the 575 appears to have 12 coil packs https://www.eurospares.co.uk/parts/ferrari/575m-maranello/engine/injection-ignition-device-36608
Actually when I think about it, the car seems to have that problem when starting from cold most of the time when it happened. What should be the cause of that?
Do you know which bank? We don’t seem to get many problems with 575’s, so our experience is limited. I don't have any books on the 575. If an engine is running roughly, we would normally look for fuel feed problems, spark/timing problems, fuel ratio problems... but to have no faults in the ECU and have the revs limited doesn’t make sense to me. The Ferrari 360 seems to have a similar engine management system. I found a reference to 4000rpm in the 360 manual, but it's not a limit imposed on the system. 4000rpm is a trigger for "open loop" engine management mode. I'm wondering if certain sensor data is missing for open loop to operate normally? But again, missing data usually triggers messages or warning lights. Is the 4000rpm limit an approximation, or does the engine stop accelerating at 4000rpm (plus or minus 200 rpm)?
No single cause. I'm just trying to narrow the range of possibilities. When the engine is cold, the engine management system runs in "open loop" mode (That is, the oxygen sensors are not used for fuel/air mixture control until the engine coolant has warmed up). These problems are difficult to diagnose when we can't see the OBD2 engine data. If we can see the data, and it looks ok, then we move on to things which the engine ECUs have less control over (things like fuel pumps, fuel pressure regulators, partially blocked fuel filters, etc). There may be a problem with injectors, but I don't see a whole bank shutting down because of one faulty injector. With an engine with two fuel pumps, two engine management computers and mostly duplicated sensors, faultfinding becomes easier because you can interchange components to see if the problem swaps to the other engine bank. Unfortunately, you have an intermittent problem, so it could take some time to find a solution. Does your mechanic specialise in Ferrari's?
Could also be an intermittent fuel pump not working. Make sure there is no gasoline smell in the trunk area. Bad ground strap, etc. Lots of potential problems.
