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Discussion Starter #1
I have a little sputtering problem on my Mondial t when I first run it in the morning. After about 30 minutes, it goes away. I've added injector cleaner in case it's clogged injectors, but a mechanic friend of mine is certain it's a timing issue caused by pre-ignition. The reason it goes away after a while is due to the fuel vapor build up. He contends platinum plugs are the way to get rid of the issue.

My question is (for those in the know) do you use Iridium or Platinum plugs? I figured Iridium would be best based solely on the cost, but I understand that it doesn't conduct a spark as well as Platinum or even copper and it robs the car of power as it runs. Iridium does get rid of the pre-ignition, but so does Platinum.

Which do you use?
 

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First the plugs - the local Ferrari dealer in my area reckons that the rara-metal plugs are over-rated, in that the special stuff is just a coating that gets burned-away fast. They don't reccomend them.

Now the "pre-ignition" - I can't see how pre-ignition can be occurring off a cold-start. It takes a super-hot source to be able to pre-ignite the mixture before the plug does, and you'd at least have to get the combustion chamber up to temps before it could even begin to happen. Second I would have thought it could only occur under high compression loads (ie full-throttle or similar), when the chamber pressures are sufficient to generate a high temp prior to sparking. Again I don't imagine that you are doing this during warm-up.

IMO it's more likely to be part of the FI circuitry / sensors. There are a few things that could be the culprit - try a Bosch FI specialist.
 

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Yeah, I can't imagine the sputtering would be from pre-ignition. More likely it is incomplete combustion. A stronger spark may help it.

I use just regular NGK plugs in the 308. No problems. I have heard mixed reviews about the benefits of the platinum. Now on my Jeep I have the "Split-fire" spark plugs. Supposed to be the best thing since sliced bread. I did not notice any performance gains with them but I tell you what, they lasted 10 years.
 

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Discussion Starter #4
Appreciate the information

I've done some reading on copper vs Platinum vs Iridium, and there are some benefits, but it appears copper changed regularly are pretty effective. As far as the sputtering goes, it just feels more like air/fuel issues, which is why I would agree it is more injector-related than spark plugs. I'll see if the cleaner helps and take it in if not. The 30K service was just completed in Dec, so I hope it's nothing too big.
 

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Re: Spark plugs:Iridium or Platinum to handle cold pre-ignit

brewnz said:
I have a little sputtering problem on my Mondial t when I first run it in the morning.

Pre-ignition can be caused by a fuel mixture that is too lean, or by spark-firing Timing that is advanced too far, or by too low of a fuel octane, or by too hot a chamber (especially if there is carbon built up inside there over time).

If you've got the 3.4 motor in your car, then you've got the same two mass air flow sensors in your Mondial T as I've got in my 348 Spider, so to adjust your air to fuel ratio you'll just pop the blue disposable caps off of each sensor, insert a regular screwdriver, and turn clockwise to "thicken" the air to fuel, counter clockwise to thicken the fuel to air. Whatever change you make on one sensor, be certain to make that same change to its brother sensor on the other side.

You can measure these changes with a simple radioshack Ohm-meter on the mass air flow sensor pins #1 and #6 (the pins one the extreme edges of the line of six electrical data pins beneath/behind the rubber-covered connection cable on each maf). The stock setting is 383 Ohms.

I'd guess that turning as little as 90 degrees (i.e. a quarter of a circle) counter-clockwise would enrichen your fuel enough to get rid of sputter IF (big "if") it is your mixture that is causing pre-ignition.

But this is essentially a free and easy fix, and certainly a free test. If you can turn a screwdriver a quarter of a turn, twice, then you can enrichen your fuel mixture.

So you try the above first...

...If that wasn't your problem, then reset it to your original positions above and try step two.

You check to see if your octane is to low.

Add an octane booster. start the car when cold.

So you try the above second...

...If that wasn't your problem, then try step three.

If your chamber is too hot, it could be either from spark plugs that are gapped too wide, or from carbon buildup. OEM Ferrari sparkplugs for the 3.4 engine are just $1.67 each Champion copper plugs, so it's pretty inexpensive to to gap 8 new plugs to less than .028 inches each, per the factory. Add a good engine/fuel cleaner to clear out any carbon buildup.

Now start her up cold again.

So you try the above third...

...If that wasn't your problem, then try step four.

Step Four is that pre-ignition *isn't* your problem...that your sputtering when cold is from spark plug misses.

Misses could be from bad gas (e.g. water), bad voltage to the plugs (holes in wire insulation, grounded wires, bad ground, faulty electrical components, plugs gapped too wide (e.g. more than 0.285 inches), bad plugs.

Add a good gas cleaner like B-12 to your tank (better yet, add Red Line's fuel cleaner), check your wires, you've already replaced and gapped your plugs in step 3, and start her up cold again.

If she still sputters, then begin replacing electrical components (e.g. plug wires, etc.) in sequence.
 
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