Huge 348 startup problem

Here's the original description of what happens when I try and start the car (hot or cold makes no difference):

"At the moment when I start the car it idles rough, and in the background of the engine noise you can hear a bom....bom...bom, almost like a miss-fire sound. Black smoke can also be seen coming from the exhaust. After about 2 or 3 minutes the idle settles down and the smoke disappears. Also, this whole startup problem occurs no matter how long the engine might have already been running, ie as soon as you stop it and re-start the same problem occurs."

After countless hours in the shop my mechanic is at his wits end, though he seems to have the problem somewhat isolated. To date he has done the following:
1) put in new coolant temp and oxygen sensors
2) swapped the left / right ECU's over
3) swapped the fuel injectors over
4) swapped the fuel pumps over (also verfied that they're pumping at the correct pressure)
5) checked the fuel pressure regulator

The left coil was disconnected resulting in smooth engine start up of the right bank of 4 cylinders with no mis-firing, no smoke burning, generally everything looked fine. Reconnecting the left coil caused the problems to return. My mechanic removed the fuel injectors to actually see how they performed when starting....the left side apparently went crazy, with "huge" quantities of fuel injected. He said to paint the picture properly you need to imagine the joint where the exhaust manifold meets the muffler (i think), there was petrol dripping out from there.

This seems to fit the scenario I described at the top. At start up the left bank of the engine is being flooded with petrol causing ignition difficulties. The 2-3 minutes it takes to settle down is probably the time it takes to burn off the excess fuel, and hence the reason for the black smoke on start up. And finally, to cause more confusion, this all happens each and every time the car is stopped and restarted, almost as if the start mode of the computer/car is stuck or not functioning correctly.

Please, please, if anyone has any suggestions, no matter how crazy or far fetched, let me have them. As I said my mechanic is fast approaching the time when he'd be willing to try just about anything.

Cheers
Warren

do you hear a rattle when you shut down?

When the car first went into the shop it used to rattle when shutting off every time. my mechanic didn't say anything about this initially, though after several starts he said, and I'm trying to remember now, the "crank shaft" snapped. Anyway I paid for a replacement and now the rattle is nearly completely gone. I say nearly because occasionally there is a rattle, though much more subtle or minor now.

I gave up on my mechanic (he was formerly employed by the sole Ferrari dealer here in Dubai) and have decided to book the car into Ferrari. I hope that after a diagnostic check they'll be able to find the problem. My mechanic literally spent months trying to trial-and-error fix it without any success. What I thought would save me money has turned out to be a huge cost in time.

What is the latest info on your situation?

Well, my mechanic and I finally got to the bottom of the problem, though things still aren't what I'd consider 100%. It turns out that the wiring from the camshaft sensor to the left engine ECU was not working. This has now been fixed and all smoke, flooding issues have been resolved.

The engine startup is still not perfect, and part of me wonders whether age has anything to do with it. I'll let you know more in the next week or so.

Have a look at the crank possition sensors, and check the temperature sensors that are located under the intake plenum. Be sure that the wires under the protective boots, on the connector, are in good condition. Also make sure every thing is cleaned and connected properly. I would also check the condition of your spark plug wires.

After you do that have the ecu's relearn the warm up process. Disconnect the battery for about :30 seconds then reconnect it. Start the car and DO NOT touch anything, not the throttle, not the break, not the clutch, nothing. Let it idle for about 15 minutes, or until the radiators fans come on at least once.