F512M Help!

asked this question here before but had gotten no responses. my F512M has been experiencing intermittant losses of power with some cylinders shutting down during regular driving both hot and cold. this could last anywhere from a split second to a couple of minutes during each occurance and the tach will drop when it happens. it also happened once when idling and the idling speed droped from 1000 to 500rpm, dealer changerd spark plugs and all sensors (temp and oxygen) but still couldnt cure the problem. where is the bug?!?! any insights much appreciated!

 

I do not know your car, but on the Boxer, it was the combination of a faulty fuel pump (of two), and crud in the fuel take cluttering the filter causing temporary starvation. When this happened, the car ran on 6 cylinders.

 

It seems more like it's ignition related than a sensor issue. Sometimes unplugging / re-plugging in of electrical connectors can cure some intermittent issues like this. So try that, maybe clean connections if needed. Check out the ignition coils and their connections carefully. As ft328 pointed out it could also be fuel related, so look at the connections in the fuse panel too.

 

Changing all those sounds expensive not to be the culprit, I have no expierence in Ferrari engines but I will try to check some other things...is it running any check engine light?

1. First plug wires, that may cause random misfire and could last a while or a split sec.(with engine running you can test wires with a water spray, in a dark garage or at night, spray a little water over the wires and if having bad wires, water will create connections in between the wires through the air and into the block, resulting in a blue mesh of electrical pulses jumping from the wires to the engine block, cheap way to find the leaking wire if damaged)

2. Check injectors:

This needs to be done while misfiring, while the engine runs rough, start disconecting the injectors one by one, if properly working, engine speed should decrease making the rough running worse, re-plug until you find an injector that is not making any difference...that will tell which one or two might be dirty/leaking/clogged...same procedure with wires but is kinda risky and with 12 cilinders to check, not every wire is easily reached to be disconnected...better the water spray...

3. Check spark...much like the last procedure, disconnect plug wires one at a time, get an old plug and plug it, and get the plug electrode close to the engine block to see if there is a spark...doing this with all 12 might be a pain but most surely track down the problem without changing random parts from the Dealer

4. Check fuel pump pressure...you´ll need more that household tools, but if you can get your hands on a pressure meter, and hook it in the gas line that reaches the plenum you´ll be able to see if there´s a drop in pressure...but electrical pumps love to go once and for all...might experience some overall pressure that is perfectly easy to read on a meter...

5. try running an injector cleaner.Deposits and water on the tanks of cars that are "garage queens" have more time to build up and end up clogging injectors...

Well, those are everyday tips, not high end mechanic tecniques but might help you get some light in the tunnel.

Hope I helped.

 

I had similar problems with my 512TR, you must make sure all muti pin plugs are clean and properly aligned,especially the two ECU's just behind the seats,also the plugs at the end of the oxy sensors and thermocouples coming from the exhaust units. then check all fuses and relays !!! look for overheated wires and bad earths. it sounds like lots of work but only takes a little time and will often cure this problem, last thing spray all connectors with a proper electrical contact cleaner, NOT WD40 !!, hope this helps

 

thx a million guys this is really informative Bazzis did you cure the problem on the basis of what you had set out in your message? any particular culprit identified?

 

it cured my problem, but I've been told that its a common problem that can keep recuring. the wiring on these cars is not of the highest quality.............